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View Full Version : Overheating problems after thermostat has been changed



Marcus.M26
07-13-2017, 07:17 PM
Hello, I was wondering if anyone has any answers or can explain. I drive a 2001 a4 with the 1.8t.

some background.

A little over a year ago I had my timing belt and water pump changed (it was due, but the thermostat didn't get changed during this...). Things were fine until in last summer my car developed a coolant leak. I always made sure there was enough coolant and water in the tank while driving and I kept spare coolant in my trunk, but during all of this my car NEVER overheated. the needle was always right there in the middle even when the coolant level was low. ALWAYS.

fast forward to finally getting the coolant leak fixed this past year (among other things that were needed). Directly after this though, the leak was fixed but now my car stays between the middle and the first notch to the right. moving around a bit.
we learned though that the thermostat that was put in my car was not from audi, so we got one from audi and fixed that immediately.

NOW the car stays in the middle, but when i turn the car off and come back soonish (say maybe ten minutes or so average), the needle is between the middle and the notch to the right once when i turn the car on (luckily it goes back after running for a minute). HOWEVER this NEVER happened with the thermostat that I bought the car with. I have been ignoring this though because I read that other people had a similar problem and I shouldn't worry too hard.

Well now today. ( today was a super hot day, heat index 100+ and i definitely had my A/C blasting to keep cool). Today when i was sitting in a parking lot my car (while running) decides to start overheating. i first noticed when the cold air went hot for a second. well I immediately turn the a/c off and the needle went to the middle very slowly, but it made it there. So after I was done waiting and I started driving, i put the a/c back on hoping things were fine. well they weren't, and my car got hot (all the way to the first notch to the right). (also, possibly related, while in stand-still traffic while this was happening I think i heard a tick sound coming from the engine, this went away when traffic started moving and I didn't hear it again though). so, I turned the a/c off and started blowing the heat out the windows to try and remedy this. luckily this let the engine get back to the middle notch (despite being miserable with the heat and the weather) I made it home with the car.

Do you think todays fiasco was only due to the external temperatures? and even if it was, should cars act like this without anything wrong? also should I worry about the engine heating up when i turn it off and come back a few minutes later? I just feel like I didn't have any of these issues before getting the thermostat changed (we thought it was in part to the leak, but other things were changed too and I think it was actually a hose and/or the cracked reservoir) and I regret having the thermostat changed at this point.

I am sorry there is so much to read, I just want any input to be fully informed on my frustrations. Thank you all so much in advance for any input you have and/or thank you for reading.

maxiz1
07-14-2017, 06:09 AM
Did you check the operation of the electric fan in front of the radiator?

V70R
07-14-2017, 10:16 PM
Electric fan should be working since his a/c system is functional. Couple questions- did a shop do the work? If so, hopefully the cooling system was bled or you may have an air pocket. How's your heat during winter and fall? In the past few years I've repaired a few B5s and B5.5 Passats that would overheat during the summer, the culprit being restricted cooling systems from heater cores and radiators.