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Discussion Starter · #1 ·
So before we send the mk4 to the scrap yard in the sky, i'm reaching out in vain for any ideas. Its a 1999 1.4E. Still only got 94k on the clock and went straight through the MOT as usual with no issues at all...except emissions. At 4000rpm it starts puffing out blue smoke. Garage say its burning oil. No leaks. Throttle body is spotless, Lambda sensors good, breather pipe nice and clean. I even tried a bottle of that "ring seal" stuff u can get. Did nothing...any ideas ? Still got 3 weeks on the MOT. Really love this little car, really want it to carry on.
Thanks in advance
 

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Either PCV, rings or valves. Light loads and high RPM will cause quite a vacuum so can easily draw oil into the combustion chamber. Could try disconnecting the PCV entirely and see, that's easy enough.

After that, check compression. After that, pull the intake and look for evidence of oil passing through the stems.

Or, find another tester...
 

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or replace the engine with one that isn't burning oil... sure it can be repaired if you want to go that route but imho with it being a 1.4 a replacement engine from a scrappy that has less miles n it might be cheaper and can be done easy enough by yourself...
 

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Discussion Starter · #4 ·
Either PCV, rings or valves. Light loads and high RPM will cause quite a vacuum so can easily draw oil into the combustion chamber. Could try disconnecting the PCV entirely and see, that's easy enough.

After that, check compression. After that, pull the intake and look for evidence of oil passing through the stems.

Or, find another tester...
Many thanks...PCV was my next port of call. Its just a little tight tbh. Didnt realise that unplugging it is an option/test. Nice call.
or replace the engine with one that isn't burning oil... sure it can be repaired if you want to go that route but imho with it being a 1.4 a replacement engine from a scrappy that has less miles n it might be cheaper and can be done easy enough by yourself...
hmmmm....another good point
 

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so thats the connection to the filter box at the top yeah?
The one on the left, yes, as you look at the engine. It should go down the back to a black box.

Disconnect it at the airbox, won't need to block it off if it's only short term - the PCV on the 1.4 is into the airbox and not direct into the manifold, so the MAP sensor reading shouldn't change. Chances are you'll open up your airbox and see the filter saturated with oil from where it sucks through the airbox.

I believe the 1.4 suffers with ring wear, so don't expect a miraculous drop in blue smoke by disconnecting the PCV. They also do suffer with the oil separator/PCV unit getting clogged up, so definitely a possibility though. This will be obvious if the pipe is full of gunk when you disconnect it.
 
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