My 2001 Audi A4 1.8T Quattro has no heat when idling. Recently, the thermostat, water pump, and timing belt were replaced. The car ran perfectly for two weeks before the problem returned. The mechanic used blue coolant instead of the recommended red/pink. Could this cause corrosion?
After noticing low coolant, I topped it off, but the issue persisted. Suspecting an airlock, I bled the system, releasing a large amount of steam. Now, I’m struggling to bleed the cooling system properly. Even with the engine at operating temperature, little water comes out of the bleed valve, mostly air and steam, especially without revving the engine.
Could the water pump have failed again, or is it a blown head gasket as my mechanic suggests? There’s no sweet smell from the exhaust, and the oil cap shows no signs of milky residue. I’m considering using radiator flush to clear potential blockages. The heater core hoses were also disconnected and flushed with clean water in both directions, but the problem remains.
I’ve tried bleeding the system with the engine running at 90 degrees Celsius, but still no luck. The water pump was just replaced, so I’m hesitant to believe it’s failed again. However, the excessive air in the system is concerning.
Is there anyone who has experienced a similar heating issue with their 2001 Audi A4 1.8T Quattro? Any advice on diagnosing and resolving this problem would be greatly appreciated. Could the incorrect coolant type be contributing to the issue? Should I try a different bleeding technique? Or am I facing a more serious problem like a blown head gasket?
While the lack of typical head gasket failure symptoms is reassuring, the persistent heating issue after replacing key components points to a remaining air pocket in the cooling system, a possible restriction, or potentially a faulty new water pump. Further diagnosis is necessary to pinpoint the exact cause. Could a pressure test of the cooling system help identify a leak or other underlying issue?
