I replaced the thermostat in my 97 A4 after it wasn’t warming up I put g12 and distilled water back in the system and got all the air out of the system which proved to be a pain in the ***... anyways since then the car warms up like normal and sits in the middle for a little bit then it will over heat, So I’m curious if anyone else has had this problem like there is something blocking the thermostat from opening, I want to know what you have experienced and yes the air is out of the system... I know the thermostat is not opening cause I have a IR thermometer and bottom hose never came about 45 degrees and the hose going into the heater core was overabout 130 at an idle I cant remember what it was after I went for adrive but the bottom hose never warmed up.

 

nobody? has anyone ever gotten a bad thermostat from an auto parts store? or if its not perfectly straight can it not open?

 

if oyu think its bad pull it out and put it on boiling water to see if it opens.

also are you sure you got all the air out.

 

could have put it in backwards

 

Im sure the air is out, and the big spring side goes towards the motor? thats the way the old one was in...

 

Yup, the big spring side does go toward the engine itself, not the front of the car.

It's possible that you got a bum thermostat. While I haven't had it happen lately, I did have it happen on my old Volvo. Just because of what a PITA it is to replace them on most modern cars, I check them all with the pot o' hot water before installation, just for that peace of mind.

If it's not perfectly straight you might have sealing problems, but that's not going to stop it from opening.

Strongly sounds like you just got a bum thermostat.

 

I don't think you have a bad thermostat, i think you forgot to put the "check ball" on the thermostat at 12 O'clock when you installed it, if this is upsidown then the thermostat will open at the wrong time.

 

can you explain more about that, I read in the chiltons manual about that yesterday and that is a posibility cause I didnt know anything about that when I put the thermostat in but, In the manual It only refered to it when talking about the v6 a4s, Im taking it back out tonight hopefully Ill get it to work right as much as that car is pissing me off I miss driving it...

 

I got the old one and theres no check ball or anything to for you to designate to put to 12 o'clock were going to test the old one in water right now to see what happens

 

Im almost positive I found the problem, The belt to the water pump is loose, as in not tight enough to turn it, is there anyway to tighten this? let me know Im going to search, while Im waiting but hoping someone gives me an easy fast answer...