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Discussion Starter · #1 ·
The Bora started running cold a few weeks ago. I assumed the thermostat had stuck open, & replaced it, but it didn't make any difference. Put a new Coolant temp sensor in too.

I've spent ages trying to clear any possible air locks, but to no avail. I thought that the water pump impellor might have broken, but there's plenty of flow into the header tank.

If I hold the revs up over 1200rpm eventually it will get up to 90 degrees, but as soon as I let it drop down to 900 rpm it starts to cool down again. I can get the bottom hose hot but after a short drive it's stone cold again.

I'm stumped as to what the problem could be.[8o|]

Any ideas?
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