A4 1.9 TDI 03 engine not warming up.

**Dubbs75** · 10-04-2016,11:47 AM

Hi guys,
New member here, so be gentle. I've had my A4 for about a week and a half. Most of my journeys are up and down the motorway for about 25 miles. This I believe should be plenty of time for the engine to reach 90 degrees, but it was hovering around 70. Looking online it suggests that the temp should be 90 degrees and the problem should be the thermostat. So I took it to a garage yesterday and they confirmed an issue with the stat so it was changed. Now the temperature bearly gets above 50 degrees so I took it back to the garage and the guy said it's fine, but I'm concerned this is not the case. Have you guys seen this problem before? Any suggestions welcome!

**Rob69** · 10-04-2016,12:30 PM

coolant temperature sender would be the next thing to check / change. the garage is fobbing you off at 50 degrees, it should sit bang on 90 after about 10 minutes driving.
previously did you find the temperature would creep up towards 90 in traffic but then drop off once you were on the motorway with good airflow through the radiator, that would point towards the stat having failed ? Also recheck your coolant level and that heat comes out of the heater vents as the heater matrix can get airlocked after coolant draining.

**Col** · 10-04-2016,12:43 PM

Yes, as Rob has mentioned, the coolant sensors are notorious for their unreliability.

For future refernce and to anyone else who reads this; If there are temperature gauge problems, it is good practice whilst the system is drained down, to replace both the thermostat and the coolant temp sensor. It saves having to do the job twice.

For a lot of garages this is not in their best interest as they will be able to charge another hours labour for another simple job. A good garage will at least have the conversation with you and advise changing both so you can make a decision.

**Dubbs75** · 10-04-2016,12:44 PM

No matter how I was driving, be it on the motorway or town driving the temperature would never get above 70, it was always 60 to 70. I'll check the levels and heaters just in case but they were all good a few days ago.