Okay so I purchased an overheating 1997 a4 2.8 12v. Guy said it was a thermostat so stupid me didn't try to diagnose it and just changed it out. (Replaced timing belt uponexamination also) Now the car is still overheating. At idle and during city driving. I've not tried highway driving yet. And I made sure to use coolant from the Audi dealership. This is both my first Audi and first car without a radiator cap.

I've not seen any evidence of coolant in the oil, no bubbles/milky color on the dipstick nor under the oil cap. After I changed the thermostat I blead the system, however I forgot to wait for it to warm up before I blead it. Then it overheated again so I then decided to blead again while it was overheated. Then some fluid came out at first but then was just nothing but steam from the bleeders. Today when I got home I made sure there was coolant and this time I waited til the coolant temp gauge was at the half way point and I blead it again. This time the bleeder hose hole squirt coolant over a foot high (didn't happen on the other two bleads). But....it still overheated.

Also I have no heat in the vehicle when I crank the temp all the way up. I have looked under the dash and verified that red actuator arm is moving when I change the temp and sure enough it is. AC works fine. The electric fan however ONLY comes on when the AC is on, regardless of what the coolant temp is. Is it supposed to be like that? How could I tell is the fan clutch is bad? I guess i should get the stuff do do the garden hose flush on the heater core.

Please Audi enthusiasts, help me diagnose my first serious cooling issue as well as my first Audi. Also I don't think it's related but in case it could be I'll mention it. The car takes a while to start. I have to crank for a few seconds, stop, then do it again before it starts up. I figure that's probably something in the fuel system and something I'd diagnose after I took care of the overheating. In case you're wondering I got a 87 a4 vg manual quattro 150k miles for 800 bucks.

 

Had car scanned today. Only code P0141 and O2 code so not related. CEL isn't on.

Anyways, I felt the upper and lower hoses as well as the radiator today to see if they were getting hot. Upper radiator is getting hot, lower is not. Radiator is getting hot near the upper hose, but it's not getting hot near the lower hose. What this means exactly? Idk that's what I'm here for. I guess it means eiher the thermostat or water pump is bad. Or the radiator is clogged? How can I check if the radiator is clogged? Can I flush the radiator myself?

This car also sat for a year and a half. Not sure if it was overheating before it was parked or not. And yeah I made sure to get coolant from the Audi dealer.