I have a 1993 Audi CS 90. The car has over 130,000 miles on it. I have had constant overheating problems with the car. No mechanic in Indiana seems qualified to repair the car and I have had what I would consider to be at least two bad repair jobs done, for the same symptoms, and they are still not fixed yet.

The car runs hot. Almost instantly. If you keep it moving it won't overheat. If you have to stop at lights, it will. The cooling fans work, but only come on when the car is right on the verge of popping. I have had the timing belt, water pump and thermostat changed. The problem persists. Just yesterday it escalated. Now, no matter how hot the engine temp gage is, smoke of some kind is starting to come from under the hood. It happens within about two minutes of driving. It smells like something is burning and appears whiteish in color. It is coming from between the engine and the firewall, from down low. The coolant does strange things as well. It all goes into the engine, leaving none in the overflow, then when the car is about to overheart, if you loosen the cap on the overflow resovoir, all the coolant comes rushing into the box and fills it to the brim.

Also, the car has an idle, acceleration problem in the mornings. You start the car, starts fine. Put it in gear, either drive or reverse, and step on the gas and the engine gurgles, pops, looses all power temporarly, maybe backfires, putters, then regains all power and rockets off. It does this primarily in the morning, but may do it all the time. Just depends. It usually does it only in first gear. The car has a manual transmission. The cars heater is sometimes not acting right either. It blows hot air, then cold, then hot.

The car is fun to drive, even with these problems, but the Audi is breaking my bank account. There are only a few mechanics who work on them. The dealership repair shop sucked. The smaller repair shops are filled with high school flunkies who only work on Chevy Novas. I just can't seem to find a mechanic that can solve these problems.

Does anyone have any advice? Why would these problems persist? What might be causing them? What should I look for....besides a new car.

Oh, and one more thing, some kid at one of the Jiffy Lubes put my oil plug on so tight that no one seems to be able to get the damn thing off. Three different places, the damn thing won't budge. I haven't looked, but I'm sure that they have rounded that bolt. The car needs an oil change. Any ideas on this one?

Appreciate your help.

Chris

 

For the overheating problem, make sure all the air is purged out of the system. This is consistant with your heater problems. There are two air purge valves, one is on the top of one of the heater hoses, right where the hoses go thru the first firewall, a black flat plastic knurled ****. Be careful with that one, they tend to snap off if they haven't been opened in a while. The second bleed valve has a alen key socket head. It is located on the U shaped black metal coolant pipe, about 1 inch diam, which winds around the base of the intake manifold, a littele down in the V of the engine. The screw is located on the drivers side of the U, near the rear of the engine. (The U is upside down, when viewed from the front of the engine compartment. Loosen this screw a few turns, just enough to let trapped air out, until antifreeze runs out. Don't fully unscrew/remove it, as it will be difficult to get it back in.

The other thing you should check is the electric cooling fan. It actually has three operating speeds. The lowest 1 is engaged whenever the AC compressor is on, regardless of the engine coolant temp. The 2nd speed is controlled by one contact of the fan thermoswitch (screwed into the bottom passenger side radiator plastic end-tank). It should turn on the fan when the temp gauge reads about 1 o'clock. The 3rd, highest fan speed is controlled by a second contact of the thermoswitch, and engages when the temp gauge is at about 2 0'clock. Also check the two (or three) relays which control these speeds, which connect different taps of the fan resistor. Check the fan resistor too. It is located on the drivers side of the car, from underneath, right next to the radiator, near where the front bumper shock bolts to the unibody frame rail end. Note the schematic of the whole radiator fan/thermoswitch/resistor/relay system was revised early in the 1993 model year production, ther are two schematics given. My 1993 90S, built Nov 92, actually is a combination of the schematics!

For your idle problem, it is most likely the IAC (Idle Air Control) valve, which tends to get stickey, and cause the car to stall. This seems to be a very comon problem on higher mileage 2.8s. Remove the IAC, and clean with solvent, and your idle problems will be solved for another 30K miles. Search archived forums for removal / cleaning procedures.

 

On the oil bolt, it is a 17mm socket. If it is indeed stripped, try using a 6-point 17mm first, and then a 16mm six-point socket, pound it on there, and then get a very long breaker bar for leverage, and pull (don't push) with all your might. When you do get it off, be sure to put a new metal gasket on with your new plug. Then go back and use it on the guy that got the bolt stuck in the first place! (Just Kidding)

 

Are you sitting down?? You need to!!

What you are explaining is a blown head gasket or a cracked/warped head. At some point you must have overheated the car by stopping too late. Hows your oil look? Usually with the above problems it gets a little milky.

It's running rough because the coolant is leaking onto the spark plugs...and runs worse in the morning because the water "pools" over night. The white smoke you see is actually steam from the anti-freeze being burned off. Do you see any steam coming out your tailpipe yet? I bet your going through anti-freeze like mad.

Sorry to be the bearer of bad news!!!

For your sake I hope you just "popped" the head gasket!! I cracked a head on an old Saab I used to own and it's not cheap to fix. I also just had a mother-in-law warp the head on her Isuzu(and she swears she never let the car overheat...she just ran it to the brink a LOT).

Good Luck!!
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Andrew
90 80Q
91 90
95 90Q