Volkswagen Mark IV Forum banner

1 - 20 of 141 Posts

·
Super Moderator
Joined
·
8,768 Posts
Discussion Starter · #1 ·
I'm sure a lot of you are getting tired of seeing the same old
questions being asked time and time again (eg MAF sensors, leaking
washer hoses etc…) so I thought that it would be a good idea to post an
FAQ / common faults thread, which will hopefully be made sticky [;)] .
SO…….. as I'm a bit thick in terms of technical knowledge I'm hoping
that you will help out by checking the info that I've posted below and
letting me know of any mistakes I've made, other common faults,
remedial action and, if possible, a link to a "how to".

For everyone's sanity, please help out!! PM me or post any advice here and I'll add it to the list. Ta.

Disclaimer:
Any advice given here is only a guide and is not to be taken as a
diagnosis of a fault. If you decide to follow the advice given here,
you do so at your own risk. Where possible, it's easiest to run VAGCOM
and check for any error codes.

My headlight / sidelight bulb has blown. How do I replace it?
Opinions
differ on this one but I found it was easier to remove the bumper and
the headlight unit to replace the bulbs. Others have done it in situ
but it can be quite fiddly. This link will help with bumper removal.
Link to: Bulb replacement

My car has flat spots when accelerating.

Possible
causes are a faulty or dirty MAF sensor, split turbo hose, faulty EGR
or N75 boost control valves. These don't always appear as faults on
VAGCOM. MAF sensor appears to be the most common fault. Cleaning the
MAF may help but ultimately, it needs replacing.
Link to: MAF Clean and MAF Replacement

How do I remove my OEM head unit?
Cut
a sturdy but no longer required credit card/plastic card into 1cm
strips lengthways. Insert these into the slots located on the left and
right hand lower sides of the HU and it will unlock and you can then
remove it.

My W8 Interior light rattles like mad with even moderate bass.
Take
light out; split top cover from base unit by releasing clips; then
remove lense from cover again by releasing clips. I superglued the
lense back in and wedged small lumps of blu-tack between cover and body
of light. (pikey but effective) and no more pesky rattles. Also useful
if you want to colour code W8 light for an Anni as you only need to
spray the cover.

My rear washer isn't working.
It's
likely that the washer hose has detached, probably from the motor.
Sometimes it can detach in the pillar / roof lining but you'll probably
notice a wet patch.
Link to: Washer repair (tailgate) or Pillar

My car keeps stalling / misfiring.
This
could be caused by a faulty MAF sensor (again), temperature sender,
relay 109 (diesels only), dirty throttle body, faulty coilpacks
(petrol) or dirty contacts on the ignition amplifier (AGU 1.8T Engine
Only). Relay 109 - the sure-fire sign is when you try to start the car,
the glowplug lamp stays out. After a few tries, glowplug light comes
on, car starts.

My window has fallen into the door.
The plastic window regulator has probably failed. Repair kits are available, which contain metal clips.
Link to: Imagewerx Regulator Guide - Vortex Window regulator repair guide

My central locking / door lock / alarm isn't working.
This
could be due to a faulty door lock module. You might be able to repair
the faulty door lock by re-soldering the connections. Some people seem
to have success simply spraying with WD40. Otherwise, it's a case of
having to replace it.
Link to: Door lock module info and repair

My windscreen wipers have stopped working.
The mechanism has probably seized. You can either replace the mechanism or strip it down, rub it with wet and dry and re-grease.
Link to: Wiper guide

There's a rattle when I accelerate.
This
usually means the front or centre exhaust mount has snapped,small
amount of welding needed or you could try using some large jubilee
clips.

My cooling fans don't seem to be working correctly when the aircon is running.

Unfortunately,
this is another common fault on the MkIV. I THINK it mostly affects the
models that have climatronic aircon. To check if your fans are faulty,
Andymac recommends the following:
1. turn engine on,
2. turn aircon on,
3. make sure ECON is "OFF"
4. Check fans are running constantly IE for more than 1-2 minutes
5. if the fans do nothing then run very fast, then stop after a minute or 2 or even 3 then you have faulty fans
Link to: Fan synopsis and fix

My key-fob doesn't work
Assuming
that the batteries are ok, it's likely that the key has lost it's code.
If you have 2 keys, put one in the ignition and turn on (I'd lower the
windows, just in case!), manually lock the drivers door with the other
key. Press either/both buttons on the remote (alarm should chirp).
Manually unlock the door and turn the ignition off. It should now be
coded.

My rear seats and boot lining are wet
First of all, check the headlining. If that's wet as well, it's probably caused by the rear washer hose connection - click here for a fix. If it's not wet, it may be the rear vent seals that have perished - click here.

There's resistance in the steering followed by a strange twanging noise, especially when making slow, full lock maneuvers.
Strut top bearings possibly seized.

Boot light doesnt work
Possibly
a blown bulb but more likely the rear washer hose has popped off and
soaked the boot catch. There is a microswitch in the mechanism that
doesnt like getting wet. Remove the boot lid cover by undoing a screw
in each handle on the inside, then pull the plastic cover to unclip.
The boot catch then comes out by undoing the 2 large spline bolts. Try
drying the switch with a hairdryer after stopping the leaking hose, or
ultimately replace the whole boot catch. Can also cause the alarm to
act strangely.

Heated mirrors don't work
First check
to see if your car has them! Pop the mirror glass out by getting your
fingers behind the outer edge and pulling, if there are 2 wires
attached then they are heated. They are activated by turning on the
rear window demister. Check to see if there is 12 Volts across the 2
wires, and/or check the fuse. If there is 12 Volts there and the glass
doesn't get warm then the mirror glass needs replacing.

When
I adjust the driver's wing mirror, the passenger mirror also moves but
when I adjust the passenger mirror the drivers side stays still - is
this a fault?

This is a feature not a fault, for convenience
when adjusting for different driver height etc. To adjust mirrors, move
the drivers side first (R) and then adjust passenger side (L) if
necessary

The traction control light is coming on whilst I'm driving
This
might also throw an alternator fault code also. The light will go out
if the engine is switched off and back on. Follow the 2 small wires
from alternator to a connector at front of gearbox, the wires break at
that connector.

There's a clunking noise when I go over small bumps.
Possibly caused by worn Anti-Roll Bar bushes.

There's a clunking noise coming from the rear end when I go over bumps.
Rear
axle bushes are probably worn and require replacement. This can be an
MOT failure so best to be repaired soon after spotting.
Link to: rear axle bush discussion.

EPC light keeps on coming on.
The
epc light keeps coming on and goes when the engine is restared, this is
a brake light switch failure. go to the stealers and give your chassis
number over.. there are over 5 types and several revised version so the
chassis number is needed.

INDICATORS sticking of flashing at random intervals
the
indicators stick or dont flash with an equal time between them, the
light relay has gone this is integrated into the hazard switch.. again
a chassis number is needed

MkIV Door drop
You'll need
the appropriate Spline bit that fits the hinge bolts (to fit a 1/2" or
3/8" drive ratchet), an extension bit at least 6" long (again 1/2" or
3/8" drive to suit the ratchet you're using) and an extra pair of
hands! With the door open you should be able to reach the bolt furthest
forward (TIP: get some 2" masking tape and mask the door edge and wing
edge where you'll be working to prevent damage) you'll need to use the
ratchet with extension bar insert it between the wing and front edge of
the door and loosen the bolt. Now you'll need to release the kick panel
trim inside the car (by the go faster pedal!) this requires you to
unscrew the accelerator stop (the plastic lug under the accelerator
pedal) now with a little pulling and manouvering you'll be able to get
the trim off (WARNING: be aware that the airbag control box is behind
this panel don't fiddle with the wires !) you should be able to get at
the bolts now, a torch can be handy here! Loosen the remaining bolts
but beware i'd leave one slightly nipped up just so the door doesn't
drop dramatically! now it's just a case of adjusting it untill the door
fits correctly- don't expect to get it right first time though ! As
soon as you've got it sussed tighten all the bolts and refit trim etc !

Delocking

If you've not already done so, one of the best
pieces of advice is to delock your Golf, leaving the boot lock as
standard. Basically, delocking is a small disc that covers the keyhole.
I'm not going to go into the reasons behind this but suffice to say
it's a security issue. The kits are available from dealers.

Common 1.8T Engine Problems

Thanks to GaryM for the following information. Tip: CTRL + F will help you search for keyword in this guide

Section 1 - Symptom - Possible Problem Parts (in order of likelihood)
Rough Running At Idle - MAF, Ignition Coil, Spark Plug, VAC Leak, O2 Sensor, TB, CTS
Missfires under Boost Flashing CEL - Ignition Coils, Spark Plugs
Running Rich - Boost Leak, MAF, O2 Sensor, Coolant Temp Sensor
Running Lean - VAC Leak, MAF, O2 Sensor, Fuel Filter
Low Boost - Limp Mode, MBC, BOV, DV, Boost Leak, N75,
High Boost - MBC Setting, N75, Spark Plugs, Ignition Coils
Cold Start Problems - MAF, Spark Plugs, Fuel Pump Relay, CTS
Poor Gas Mileage - MAF, CTS, O2 Sensor, AIT Sensor
Cat Efficiency Below Threshold - Down pipe, CAT, Rear O2, RACE FUEL
No Start - Battery - ECU, Fuel Pump Relay, Ground
Start For 1 Second - Stall - Immobilizer
Overheating - Waterpump, Thermostat, Head Gasket
oil in coolant - Oil Cooler, head Gasket, Water Wetter
Dies While Driving - Timing belt, Boost Leak, MISC
Shorts To ground CEL - Fuel Pump Relay, Bad Grounds

Section 2 - Part Troubleshooting Method - Alphabetical
Most
of these procedures require a VAG com to scan the car for diagnostic
codes. While you can fix things without a VAG you will most likely be
replacing parts that really are not bad just to rule them out. A VAG
COM is a must have for any 1.8T mechanic. Details here
http://www.ross-tech.com/vag-com/cars/18T.html

AIT - Sensor
- This is a small sensor located in the intake manifold just after the
throttle body. It is responsible for monitoring the intake temperature.
It can get coated with oil, and can affect gas mileage, and a loss of
power. It is common to remove it and clean it with alcohol, or
electronics cleaner.
Boost Leak - View Block 032 with VAG
Com. If Fuel Trims are Negative more than 5% in the load range there is
a very good chance that there is a leak after the turbo. Visual
inspection of clamps, hoses for a loose connection is the best way to
look for leaks. A common place for leaks is at the entrance to the
pancake pipe located in the passenger side fender. Also the small line
on the DV can rip.
Fuel Trim Details Here - http://www.ross-tech.com/vag-com/cars/fuel-trim.html
BOV -
Blow off Valve's vent off air metered by the MAF, and can cause many
problems, and make it more difficult to troubleshoot a car. Best way to
troubleshoot a BOV is to replace it with a DV and see if the problems
continue.
CAT - Aftermarket high Flow Cats often sacrifice
emissions for power. It is not uncommon for aftermarket cats to give
codes for "efficiency below threshold" right away. Some people have had
success using O2 adapters to move the rear O2 sensor away from the
exhaust gas and eliminating this code. O2 simulators do not work on the
1.8T. Sometimes cats can melt or clog up. Running hig exhaust gas temps
for extended periods of time can cause this. Usually you will get the
cat code, and see that the max boost and sustained boost levels drop
off. After checking everything else on the list, remove the down
pipe/cat and check to see that light shines through brightly. If there
is very little light passing through it is clogged and requires
replacement.
CTS - Coolant Temp Sensor - This part is prone
to failure. 2002 and older vehicles had a bad coolant temp sensor from
the factory that VW updated. It was a black sensor, and now the good
one is referred to as a green top coolant temp sensor. Block 011 in the
VAG COM can monitor coolant temp for erratic readings. This is a 7$
part. Do not change while engine is hot.
Down-Pipe - See CAT
DV
- Diverter Valve - When the throttle is closed on a turbo car, the
turbo is spinning rapidly, and trying to push air into the engine. By
closing the throttle the air has nowhere to go, and will cause a large
pressure spike. The diverter valve is actuated by a vacuum line, and
when the throttle closes creating vacuum behind it, the diverter valve
will open and provide a path for the air. The air is returned back to
the intake of the car after the MAF. When A DV fails it leaks air in
this circular pattern causing boost problems.
2001 and older cars
have a weak DV that is prone to failure. 2002 and newer cars have an
improved design. It is durable, inexpensive (35$) and it responds very
quickly. The part number for the good valve ends in 710 N. The DV is
located at the back right side of the engine, it has 1 large hose, and
1 small line connected to it, and the other end is connected to your
intake hose running to the airbox. To test if your DV has failed remove
the DV, press the diaphragm up, put your thumb on the top nipple, and
then release the diaphragm. There should be suction created on the top
of the DV that prevents the diaphragm from returning. If there is no
suction then the diaphragm is leaking and the valve should be replaced.
IF the valve is good, check the VAC line leading up to the valve for
any cut's/ tears.
ECU - The ECU is responsible for nearly all
functions on the car. If the ECU is suspected as a bad part, you need
to use a scan tool such as a VAG com to attempt to communicate with the
ECU. If you can't communicate with the ECU, then the ECU needs
replacement. Check all electrical connections. Check your Fuses for
blown fuses. Whatever killed the ECU might kill the new one.
ECU removal procedure - http://www.goapr.com/VW/support/ecu_tt_golf_gti_jetta.pdf
Fuel pump Relay
- The fuel pump relay is located under the driver's side kick panel.
Remove the lower panels to gain access to the relay box. When the fuel
pump relay goes bad it will trigger many fault codes with electrical
shorts to ground. The fuel pump relay is also used to turn on the
injectors, and will show injector short to ground failures. If you open
your door you hear the pump kick on, if the pump no longer kicks on,
and you experience these codes repeatedly, replace the fuel pump relay.
Fuel Filter
- The fuel filter on these cars is rated as a lifetime filter by VW.
What the aftermarket has found is that high HP applications can run
into fuel delivery problems with dirty fuel filters. 30K miles is a
more realistic interval for replacement when pushing the system. The
fuel filter is located under the car near the gas tank. It has small
clip on hoses. To remove the hoses press in on the clip on the end of
the hose and it will come off easily. You may need a small screwdriver
for this, and be prepared to have fuel leaking out.
Head Gasket Head
gaskets can be a cause of overheating, oil consumption or coolant in
the oil. I have only heard of one case of a head gasket failure on a
1.8T and it was on a car running 30 lbs of boost and used head bolts.
This is a repair better left to an experienced mechanic and is
generally a last item to do after all other possibilites have been
evaluated. overheating is usually the water pump, and coolant in the
oil is usually the oil cooler failing internally.
Immobilizer
- These cars are equipped with immobilizers to prevent theft. If you
swap an ECU without matching up the ECU and the cluster, it will start
briefly and then die repeatedly. There are 2 kinds of immobilizer. Immo
II used on pre 2002, and Immo III used on 2002+. Immobilizer and ECU
info can be found on the VAG COM Site.
http://www.ross-tech.com/vag-com/cars/immobilizer2.html
http://www.ross-tech.com/vag-com/cars/Immo3-ecu-swapping.html
If
swapping an engine into a car without an immobilizer/cluster, you can
get software for swaps from REVO, and Dahlback that remove the
immobilizer.
Ignition Coils - These are famous parts for the
1.8T they are very prone to failure. VW has had a recall on these
because they were failing rapidly on 2001+ cars. To check for bad coils
the best way is with a VAG COM. Log Blocks 015, and 016. This will be a
misfire counter. Drive the car or let it run, and look for misfires. If
you have a bad coil you will see the counter increase on a cylinder. If
you have one counting up then it's probably a bad coil. Turn off engine
and take that coil out and swap it with another coil. The cylinders
read left to right 1,2,3,4 when looking at the engine from the front.
Use the VAG again to see if the misfires have also swapped to another
cylinder. If it moved, then you have a bad coil. Replace it. If they do
not move, then you likely have a plug problem. On some cars the
ignition coils have problems and they will pop up out of the cylinder
head and lose contact with the plug. Plugs should be torqued to 22
ft-lbs when changed. If the coils still pop up, and they are torqued
properly I have created a bracket kit to hold them down ? - see sig.
Limp Mode
- These cars are designed to protect themselves from engine damage. If
the engine boosts too much, or the engine does not get enough fuel it
will go into a limp mode where boost is limited to protect the engine.
It limits boost by controlling a solenoid on the wastegate line (N75),
by closing the electronic throttle or by opening the DV valve. If you
are experiencing a limp mode the best thing to do is get the car
scanned for codes and to see what is wrong. Look at fuel trims for
signs of running lean, and to look for MAF problems, or O2 sensor
problems. To look for potential boost problems log Block 115 and you
can see the specified Vs actual boost. If you exceed the specified then
there is a good chance that you will go into this limp mode. Stock
specified is a max of 14 psi for a 2002+ car.
MAF - Mass air
flow meter is used to measure the air going into the engine. It is
located on the outlet of the airbox, and housed in a cylindrical tube.
The ECU reads the MAF signal, and injects fuel in proportion to the
airflow. There are a few different ways the MAF can fail. The MAF can
get coated with oil, and will not read properly. This is common if it
happens right after installing a CAI, or a K&N filter. It can be
cleaned out with 99% isopropyl alcohol, or a quality electronics
cleaner. Remove the sensor from the housing and clean the sensor
element.
MAF sensors also go bad due to too much airflow. On a car
with a larger turbo the airflow is so high that the MAF element will
get burned out from the excess air flow. It is common to increase the
size of the housing to prevent this (other modifications required).
To
check for a BAD MAF the best way is with a VAG com. Block 002 show air
mass from the sensor. At idle the air flow should be 2-4 grams/second.
With a wide open throttle run to redline the reading should show up to
170 g/s on a chipped car. Look for jumpy readings in the MAF, which can
indicate a problem. More details here
http://www.ross-tech.com/vag-com/cars/fuel-trim.html if you suspect
your MAF is bad, one way to test it is to unplug the MAF, often if the
MAF is giving false readings and upsets the fueling. If you unplug it,
the ECU will ignore the MAF and run off of baseline tables. Be careful,
as a boost leak or a vacuum leak can be miss-diagnosed as a bad MAF,
because they will throw off the readings on the MAF. (Air sneaks around
the MAF).
MBC - Manual Boost Controller. Often people want
more boost from their car, and use a MBC. While MBC's can get you more
boost they will cause a jerky part throttle driving, and can cause over
boost, often put the car into a limp mode. The way a MBC works is by
bleeding off air from the wastegate control line. A wastegate is a
mechanical flapper valve in the turbocharger that opens to allow
exhaust gas to sneak around the turbo. By bleeding off air from the
line, the wastegate opens less, more exhaust goes through the turbo,
and you get more boost.
Great details on MBC here - http://www.boostvalve.com/tech/1.8T-DBW.html
And general Turbo/Wastegate details here http://www.streetracersonline.com/articles/turbo/wastegate.php
N75
- The N75 is an electronic solenoid valve that the ECU uses to control
boost. It is located in the intake hose near the back right side of the
engine. It has 3 connections.
1. Connects to charge pipe = pressure source
2. Connects to wastegate actuator
3. Connects to intake hose - bleed line.
The
ecu will pulse this valve at a high frequency to bleed air off from the
wastegate line. It does this based on throttle position and engine
load. If the valve, or any of the liens connected to it have leaks then
there can be severe boost regulation problems. It's function is similar
to the MBC above. To get more boost people often swap in different N75
valves. These different valves simply have a different response
characteristic, and will act different when given the same signal by
the ecu. They can get more boost, less boost, or even a big boost spike
by swapping N75's.
O2 Sensor - Because of strict emissions
these 1.8T's are very sensitive to readings from the O2 sensors. MY
2001+ have a wideband front O2 sensor with high accuracy and a linear
response. The car will adjust the fueling based on the readings from
the sensor. If the sensor is over heated, exposed to lead (race gas),
flooded with soot (too rich) or is just old, it can provide the car
with false readings and the car will not provide the proper fueling.
When the O2 sensors go bad and the ECU detects this the car will run on
reserve fueling maps and will not be able to adjust for boost leaks,
fuel pressure, MAF readings or any other parameter that affects
fueling. To check for a bad sensor the first thing to do is run block
032 on the VAG com. If the sensors are bad, the readings will both be
0%, replace the Front O2 sensor. If the sensor is bad, it will also
respond slowly, or reach a peak. Logging block 031 will show the lambda
reading from the O2 sensor as well as the requested lambda from the
ECU. To get air fuel ratio multiply lambda by 14.7. If the lgo shows
the lambda jumping wildly when running through a gear, or perhaps it
flat lines at an unreasonable level, then the O2 sensor should be
replaced. It is a 50$ part. If the o2 sensors get shorted out or the
wires get pulled, they will damage the ECU, be careful with the wiring
on these sensors. 2000 and older cars do not have a wideband sensor,
however they will still perform some adjustment of fueling based on the
sensor.
Oil Cooler The Oild cooler on these cars uses a plate and
plate heat exchanger. Oil on one side, coolant on the other side. Often
the brazing on teh cooler can fail and oil and coolant mix together.
This is often misdiagnosed as a bad head gasket. To test this remove
the coolant hoses and apply air pressure to the oil cooler and watch
for leaks. Oil cooler is located above the oil filter.
Spark plugs -
With the weak coil packs that these cars have, and the high boost
pressures that they run, the spark plugs are very important. Spark
plugs on turbo cars need a nice tight gap 0.028" is recommended. Spark
plugs may come "pre-gapped" however you should always check the gap, as
the variation can be severe and will cause problems. Plugs are cheap,
so the best way to troubleshoot is to replace them or pull them and
check the gap. A good cheap replacement plug that is a bit cooler is an
NGK-BKR7E copper plug. They need changing more frequently, however they
are cheap.
Thermostat - Thermostats can be a source of overheating.
Most common is the waterpump. Thermostats are relatively inexpensive,
and can be change din a half hour. If your car overheats, or has a
tendency to spike up in temp and then drop down to normal temp, it may
be a thermostat.
Timing Belt If your driving along and your 60+K
mile car runs great and all of a sudden dies, there is a good chance
that your timing belt has broken, or stripped some teeth. This is a
very costly repair and could have been prevented had the factory
recommended a better service interval for the belt. Damage estimates
are anywhere from 600 - 1800$ to repair this kind of failure. 60K miles
is a good time to change the timing belt, some belts have lasted 90K,
but it's not worth the risk. To test for this failure, pull off the
timing belt cover and crank the engine by hand. If the cam gear doesn't
turn you have a bad timing belt. Repair is best left to a good
mechanic. - If your going full throttle and the car all of a sudden
dies, check for a boost hose blown off -
TB - The throttle on
these cars is drive by wire, it is an electronic throttle with a wire
attached. Most common TB problem just requires adaptation, or cleaning
out with carb cleaner. This procedure shows how to do a TBA. TBA can
improve idle, and part throttle operation.
http://www.ross-tech.com/vag-com/cars/throttlebody.html. To clean the
TB remove it, and spray inside with carb cleaner. Wipe out the residue
that gets built up in there. NEVER port a TB on a 1.8T it won't idle
properly.
Race Fuel - 1.8T engines love high octane fuel,
however they can have cold startup problems, and if you run leaded race
fuel you will ruin your Cat and your O2 sensors. Always run unleaded
fuel in a 1.8T unless you are cat less, and you have extra o2 sensors.
VAC Leak
- A VAC leak will cause un-metered air to enter the engine and it will
run lean. If the air is not measured by the MAF then the fuel will not
be injected. The O2 sensor will compensate for much of this, however it
has limits. To check for a VAC leak, log block 032 and check the idle
fuel trims. If it's more than +2% you probably have a VAC leak
somewhere. Check hoses and connections for loose clamps of cut hoses
here are come common areas for VAC leaks.
Turbo inlet pipe not
secured, DV line leaking, Crank case breather Y pipe split, Line on
Fuel pressure regulator gets worn and leaks, intake manifold gasket can
leak, and PCV line under intake manifold leaks. To find leaks some
people spray ether, or starter spray around in the engine bay and
listen for changes in idle speed. If you get a change from spraying in
a certain area look for leaks there.
Waterpump - Nearly all
overheating problems I have seen on these engines has been from the
water pump. VW uses a plastic impellar that is splined/molded onto the
shaft. These splines strip, or the pump cracks and the impellar slips
on the shaft at high speeds. If your car is overheating best bet is to
change the waterpump. You can do the T-stat first to see if your lucky
but every time I have seen people try this it's the water pump anyways.
This happens as early as 35K miles. While your in there doing the water
pump, change the timing belt. Timing belts on these can go as early as
60K miles. There are several companies that make kits to do the timing
belt and water pump. www.ecstuning.com is a good one.
Water wetter
- Water wetter is an additive used to remove surface tension from
water. It improves waters cooling ability in a cooling system as it
prevents beading of the water, and raises the boiling point. Water
wetter should not be used with G12 coolant. It is best for race cars
running only water. If you add this to the coolant reservoir you get a
nasty oily sludg in the reservoir. Flush coolant system and remove this.

<End of 1.8T Guide>

Thanks
to those that have contributed to the list and to the people who have
written the original replies and links. Special thanks to GaryM who has
contributed greatly to this.

Diesel owners - for another great source of info, click here.
 

·
Registered
Joined
·
824 Posts
Slight rattle on acceleration usually means the front exhaust mount has snapped,small amount of welding needed. Have heard a few people mention it,not sure if that makes it a 'common' fault but mine's doing it ATM [:mad:]
 

·
Registered
Joined
·
1,120 Posts
Relay 109 applies to diesels only.

The sure-fire sign is when you try to start the car, the glowplug lamp stays out. After a few tries, glowplug light comes on, car starts.
 

·
Registered
Joined
·
5,039 Posts
Looks like a great start Dave [Y][Y][Y]

I'll make it sticky & hopefully more
people will reply as well, adding new Q&As or expanding on what you
have above. I think it would be best if you edited the original post to
add questions in (so it's doens't get too confused), then get somebody
to delete replies, what do you reckon?
 

·
Registered
Joined
·
23 Posts
The following items replaced under warranty at 24000 on my GT TDi 150 03 reg

New CD player

New Rear wiper motor

New Fan behind dashboard for air con
 

·
Super Moderator
Joined
·
8,768 Posts
Discussion Starter · #6 ·
Looks like a great start Dave [Y][Y][Y]

I'll make it sticky & hopefully more people will reply as well, adding new Q&As or expanding on what you have above. I think it would be best if you edited the original post to add questions in (so it's doens't get too confused), then get somebody to delete replies, what do you reckon?
Yeh, that's what I was thinking. Makes it a little easier, especially for newbies.

Cheers for the replies so far.
 

·
Super Moderator
Joined
·
8,768 Posts
Discussion Starter · #7 ·
The following items replaced under warranty at 24000 on my GT TDi 150 03 reg

New CD player

New Rear wiper motor

New Fan behind dashboard for air con
Re. the wiper motor and new fan - what were the faults?
 

·
Registered
Joined
·
100 Posts
Great idea - especially for people who have only recently come onto the VAG scene such as myself.

A guide towards all common faults and how to go about fixing them is definately the way forward - looking forward to it!
 

·
Registered
Joined
·
29 Posts
Dont forget creaking doors on three door models and drooping doors due to hinge wear. Also fan failure on the climatronic cars!!!  Ahhhh VW build quality, Think ill buy a Cit**en next time!! ONLY JOKING, can u imagine how many faults you would have on this page with one of them.....
 

·
Registered
Joined
·
1,120 Posts
If you do have a diesel (esp. non-pd ones), a cracking source of info is http://www.tdiclub.com/

If you haven't already done so, spend an afternoon securing the hose joints on your rear washer with small cable ties, to prevent them popping off. There's two places, inside the rear hatch at the motor, and at the c-pillar.
 

·
Registered
Joined
·
504 Posts
Excellent idea.

On the centre exhaust mount problem. There is a fix which works well and doesn't involve welding. Not sure if people will like it or not but i got it originally from a VW specialist who use it regularly as they find welding isn't always sucessful. I did mine about 8 months ago (now a further 2 years @Dec07 and still never touched it) and it's still going strong, you simply buy two larg jubilee clips about 2 -2and a half inch size and clamp the bracket back on. Jubilee clips are better than exhaust brackets as they dont foul on surrounding parts. I don't know if this can be added on above, i wouldn't know where to start I am afraid.

Thanks

Wallace
 

·
Registered
Joined
·
1,560 Posts
On my R32 strut mount bearings replaced twice under warranty.

Problem

Resistance in the steering followed by a twang type noise especially when making slow, full lock manoeuvres eg reversing out of a drive way.

Resolution

Strut top bearings seized. Replaced by dealer under warranty.
 

·
Registered
Joined
·
29 Posts
Thats very interesting, I recently bought a full r32 front subframe with struts to go in my 1.8t and both strut top mounts were completely seized, This was from a 3,000 mile vehicle!!!, Will keep an eye on them. PS did u know you can lower the front of an R32 for free.....there are two billet alloy spacers fitted under the top mounts approx 10mm high, remove these and you lower the front by 10mm with no probs. VW used racing springs and probably thought the ride height too low for uk roads so fitted these spacers!!!, I dont think they are fitted to non uk cars...
 

·
Registered
Joined
·
5,827 Posts
Dirty ignition amplifier contacts don't always cause stalling, it can just be a misfire, as seen on my car.

Solution: Clean contacts with contact cleaner/white spirit or maybe some light wet 'n dry to remove any heavy dirt.
 

·
Old School UkMkivs Member
Joined
·
2,166 Posts
Here is a couple I have come across

Boot light doesnt work

Possibly a blown bulb but more likely the rear washer hose has popped off and soaked the boot catch. There is a microswitch in the mechanism that doesnt like getting wet. Remove the boot lid cover by undoing a screw in each handle on the inside, then pull the plastic cover to unclip. The boot catch then comes out by undoing the 2 large spline bolts. Try drying the switch with a hairdryer after stopping the leaking hose, or ultimately replace the whole boot catch. Can also cause the alarm to act strangely.

Heated mirrors don't work

First check to see if your car has them! Pop the mirror glass out by getting your fingers behind the outer edge and pulling, if there are 2 wires attached then they are heated. They are activated by turning on the rear window demister. Check to see if there is 12 Volts across the 2 wires, and/or check the fuse. If there is 12 Volts there and the glass doesn't get warm then the mirror glass needs replacing.

 

·
Registered
Joined
·
531 Posts
Dave - that is a really great start and will help lots of people. I have a couple of minor comments - I believe that the cooling fan problems only affect the later cars (150s) as the fans are different on my PD115 - I,m not sure about the rest of the range - someone else may be able to confirm this. On the subject of water pump problems it is possible to do a rough check on the impellor once the thermostat has been removed - if it it possible to turn the impellor there is obviously a problem.
 

·
Registered
Joined
·
1 Posts
Hi I am a newbie to the Golf scene having purchased my first MkIV Golf last week (2000X V6 4motion). Thanks for the excellent FAQ section, I would like to expand/ask an extra query re the wing mirrors - my electric near side mirror goes L and R fine but when adjusted for up and down it doesn't work but makes the off side mirror go up/down! This mirror incidentally works and moves in 4 directions just fine. I wonder if it is a fuse/connection problem or is it the way the mirror is fixed in the case??!! Many thanks and keep up the good work!
 

·
Registered
Joined
·
1,451 Posts
Another common problem, with the PD especially, not sure about the petrols. If your driving along and after a few miles the traction control light comes on and wont switch off until you turn engine off and on and which keeps happeneing everytime you drive, here is usually the cause, it will also give an alternator fault code also.

Follow the 2 small wires from alternator to a connector at front of gearbox, the wires break at that connector. Its happened mine and others i know off.
 

·
Super Moderator
Joined
·
8,768 Posts
Discussion Starter · #20 ·
Another common problem, with the PD especially, not sure about the petrols. If your driving along and after a few miles the traction control light comes on and wont switch off until you turn engine off and on and which keeps happeneing everytime you drive, here is usually the cause, it will also give an alternator fault code also.

Follow the 2 small wires from alternator to a connector at front of gearbox, the wires break at that connector. Its happened mine and others i know off.
Does anyone know if this is both petrol and diesel, or if it only affects the pd?
 
1 - 20 of 141 Posts
Top