SouthernStyleA4

I have a 98 2.8 quattro a4. Twice now after the car has been driven for a while the car will start smoking from under the hood and then i will notice a **** load of coolant running out from under the car. The first time I was just parked with the car running and AC on for a while and notice the smoke and got out and noticed that the coolant was leaking out and running out from under the car. The second time after being in bumper to bumper rush hour traffic for about and hour I noticed the same smoking from under the hood but was not able to get out and look until the smoking stopped. The second time when I finally pulled over and parked my coolant tank was almost empty about the exact same amount as the first time but the car was off and the hose running from the coolant tank to the top of the radiator was like vibrating like coolant was bouncing around in it!

I believe the smoking is the coolant leaking onto the hot engine to tell you the truth because after i got out of the car the second time the car was covered in like burnt sticky coolant fumes around the grill and the driver front wheel well. I know my ECT sensor is bad because my coolant temp gauge in the car always sits on C and both times when this overheating/leak occurs the gauge might jump to H a few times.

Also recently I noticed it during the last overheating that my oil temp is running at about 250 degrees. I dont think this is normal either.

Please tell me what could be the possible cause of this! Is it possible that my coolant flange is bad? please help me out! can someone send me in the direction of a picture of the flange for my 2.8 and also a picture of the ECT sensor for my 2.8? Thanks SO SO MUCH in advance!

4Driver4

If it's overheating in traffic, but fine going down the road, it's a fan issue.

SouthernStyleA4

how can i tell if the fan is not working? and which fan would it be?

Audi0s

The coolant flange will leak from the rear of the motor. If you see an oragne buildup from coolant thats where its coming from. your oil temp is also pretty high, especially if running synthetic. If your car overheats and the fan doesnt come on its probably not working. The fan should kick on when you turn the ac on also.

AudiMick

Unless you are living somewhere really hot, the mechanical viscous fan should keep the engine cool even with the electric fans turned off.

As they get older the thermal viscous clutch wears out and they don't lockup.

Are you using the correct coolant, using the wrong type can gum up the radiator and cause this problem?

4Driver4

Never seen a 2.8 leak here.

jimrobertson

can watch it. You can also watch the fan functions as well. Then shut off the motor and see if fluid comes out when it is cooling down. The cooling system pressure will build and fluid will likely come out then. As for your temperature sensor. Look in the tech articles on this website. Popular repair issue.

Audi0s

I have, on more than one occasion.

SouthernStyleA4

The fan does not turn on when I turn the AC on... which fan is this? No I am not using the "correct" coolant... using normal green coolant. i have heard people say that its fine to use green coolant like peak 50/50... how can i flush my radiator?

AudiMick

It is never OK to mix green coolant with Audi coolant. It will turn to goo and block everything up.

It's really difficult to flush it when it is contaminated like that. Expect to drain and flush up to 10 times, and it still might need the radiator to be pulled.

There is a 2 speed electric fan, on the passenger side behind the radiator. That fan should run with the AC. Either the fan is blown, the fuse is blown or your outside air sensor is not working which will prevent the AC from running.

The viscouus fan is on the drivers side, that fan should keep the engine cool on it's own unless it's 80+ F outside.