I just bought an used 1993 Audi 100 CS Quattro. It has 160k miles on it. Its an automatic transmission. I've been driving it for a few days and I noticed that the engine coolant temperature is below the mid point even after driving on the highway for 20 minutes. Last week when I'm driving I noticed that the temperature gage kept rising pass mid-level. I drove for 15 minutes and stopped at the store to pick-up some stuff. Then when I started-up the car again, I had the engine coolant warning light come up immediately. I was only 5 minutes from my house and started to drive. As I drove, smoke/steam started to come up from the left side under the hood. I pulled over to the side and noticed that the coolant was boiling and had spilled.

Can someone tell me what could be the issue? Is it the thermostat that might have stuck open before and now stuck closed? I don't know if the fan came or not not. Not sure how to check to see if the fan is working either.

 

well Houston we got a problem.

Did you check the coolant pipes? Did you check the level? Did you check the cap?

to check the thermostat, check the lower hose. As soon as your car reaches working temperature check the lower hose if it geting hot. If it does then thermsoatat is working. If not, which is more probeble. You will require to chenage it. And in the other topic "THermostat" You can follow it.

Make sure that there is coolant in the expansion tank, the all color coolant can work.

Your car is a V6 right?

You probably have a raptured hose or something.

Do you have any coolant leaking underneath of your car?

 

Thanks for the reply. Yes, its a V6. After the overheating, coolant leaked all over and it was boiling inside the tank. Now the tank is completely empty. I'll add coolant, check for leaks, and check to see if the lower hose gets hot. Is the lower hose on the left side towards the bottom? If so, I was checking that hose during overheating and it was hot.

 

sounds to me like a classic bad thermostat and faulty cooling fan switch

 

Thanks. How do I check the cooling fan switch?

 

it very hard to do, becouse it goes by the levels of temperatures. I check it, by touching the exit side of rad, and comparing it to the entrance.

I would check firts the fans, by shortening.

its not that expensive, so you can change it.

 

I found a connector on the right fan and another connector at the bottom of the coolant tank. Where is the fan switch located?

 

ahh, its on the rad