I have a 2001 Audi 1.8t Quattro with an overheating problem that I have yet to find the culprit.

Water pump was replaced less than 40k ago. With a mental impeller. Just did the thermostat, just replaced oil cooler because there was coolant in my oil but no oil in coolant. That was last month and that solved my issue for a while. Took the car an hour away no problems. I just replaced the head gasket as well along with new head bolts and used the right torque specs even though I couldn't find anyone agreeing on exact specs but I used what most people were saying on the forums. New oil filter.

So as of right now My heat kicks in and out, mostly stays on, but can't get the car to drive more than 10 mins without overheating. Smoke comes out of the expansion tank and a little bit around the engine, mostly because it's so damn cold up here in Ohio.

So I also did the coolant flange while I was doing the head gasket. Tensioner is new along with water pump when that was done and timing belt. I also replaced my heater core supply line that hooks up to the coolant flange as well, also flushed the heater core with a rigged up process. I do notice a slight amount of oil burn as soon as I start the car but literally right when it starts and then the cars good, it's always really done that.

So as I'm driving the temp will rise at about a normal speed, and oil soon follows, then the coolant mark starts to proceed past halfway where it should stay. To get my heat to work I've tried leaving the reservoir cap off and keeping it at about 2000 rpm for a little while to try and get air out of the system as well as pulling back the left heater hose to expose that tiny hole to allow more air out. Any suggestions would be greatly appreciated. I've never dealt with such a headache with this car and I've owned it for about 5 years now. Thanks

 

Both the belt driven and electric fan spinning?

 

are te they both supposed to be on at idle? Belt driven spins but not very fast. Haven't seen the other electric fan on at idle.

 

Electric one will run if the A/C is on, defrost mode is selected, or it the car begins to overheat. If your driving over 30 mph or so the number of fans running shouldn't matter though, there is enough air flow coming thru the radiator just from the motion of the car.

Is the car actually overheating? Did you check it with a IR thermometer, or a mechanical gauge or has it actually overheated and pushed coolant out of the expansion tank cap? Is the overflow cap good, does it hold pressure when the coolant gets warm (don't try taking it off when its hot unless you want some nice steam burns)?

 

car is for sure overheating, temperature gauge is working so sensor is fine, reason I know that it's overheating is because after driving it about 10 miles it will steam because it's pretty cold where I'm at, and the overflow tank builds pressure. If I slowly loosen the cap it will hiss, releiving pressure. I just did discover that my timing belt became a little bit loose. Very strange, water pump, tensioner, pulley, timing belt are all newer(20k). So I'm going to fix that and get good tension and get it in time right. I heard that if you're out of time with the cam that it can cause hot running but there's no way it can cause this much of an overheating problem right? Thanks

 

Retarded ignition timing can make it run hot but I don't think valve timing will. If it heats up to overheating in 10 minutes time then there must either be air in the system, some kind of flow restriction, or the water pump isn't pumping anything (may be air bound - or it may have a mechanical issue). My 1.8T will barely get up to normal temperature in 10 or 15 minutes of driving (around town) this time of year let alone over heat.

Is the heat still coming and going on the inside, or is it solidly hot all the time once the gauge says the car is at normal, or higher temp?

 

after the engine is at a normal operating temp or higher the heat will occasionally come on but most of the time it requires me to have the overflow cap off and hold the engine at 2k rpm and I will have the heat on full blast and I will feel it slowly come back. Then car will still overheat. How long does it take to get the air out of the cooling system? I've also tried pulling back the heater core hose with the breather hole to let air out.

 

okay good news I think, so as I was messing with the timing belt, tensioner, water pump etc. I noticed that the main fan will spin with the pulley, but once I had the belt off I noticed that it will also spin by itself, so my guess is that the bearing is shot. My original fan had broke about 4 months ago and I replaced it with one from the scrap yard because I was in a rush but now it makes sense, I'm going to order a new one and hopefully that does the trick. Can the car overheat with q bad fan like that? I'm guessing yes. Especially since I've checked literally everything else. Let me know thanks.

 

It can over heat if parked or not moving very fast, but it shouldn't overheat if you traveling above 30 mph or so, there's enough airflow thru the radiator just from the car moving to keep the temperature down, especially in the winter.