Old_Mil

Can anyone comment on the suitability of this

http://www.034motorsport.com/engine-...cyl-p-114.html

For a 1990 Audi 100 that is starting to run warmer than it has historically (worse in stop and go traffic)? The (useless) local Audi dealer diagnosed it with a sticking thermostat (which I've replaced along with flushing the cooling system) without resolution. The car sat for 8 years so I'm eyeing the gaskets as a potential source of trouble...

I'm wondering if this will allow me to stop using premium fuel as well...

RockinV8Q

The gasket will work fine on your 100 but what indications do you have of a headgasket failure?

Are you loosing coolant?, have coolant in the oil or oil in the coolant? Are you blowing steam out the tailpipe?

If the car is running hot and doesn't have any indication of gasket failure I'd be looking at the radiator and fan not the headgasket.

As for not using premium, you don't have to use premium, the car will run fine on 89 octane. You'll just be filling up more often.

Old_Mil

Supposedly the audi dealer already checked out the fans and gave them a clean bill of health.

Also, the radiator was looked at when I had the system pressure tested, flushed, and filled with new coolant.

For the first few hundred miles after the coolant change it seemed to do slightly better (holding between the original low 'normal' mark and the next hash up and now it has gone back to doing what it was doing...

RockinV8Q

Your dealer also diagnosed a sticking thermostat, didn't fix your problem did it. Your car is 21 years old. Are you certain the dealer even has manuals to fully test any system on your car? How about a tech that's worked on a Type 44 any time in the past 10 years? Dealer techs are trained in current manufacturer offerings so unless the tech that worked on your car has been working on Audi since 1991 its unlikely he's ever trained on a type 44 or even seen a type 44 service manual

Look at your symptoms... "car runs warmer than usual and worse in stop and go traffic". That indicates a problem with airflow/heat transfer, not a head gasket.

You stated your car sat for 8 years. Its very possible your radiator has corrosion or scale in the tubes blocking flow and acting as an insulator preventing efficient transfer of heat. Its possible you have a failed temp sensor in the radiator, or a failed fan relay.

audi_marv

I'd have to agree with Rock....find a new mechanic !!! The symptoms you stated seem to point to a failed temp sensor. Failed relay is an easy fix. Is the temp range fine on the highway, but then climbs at a red light ?

Easy way to check the temp sensor is to let the car idle, and when coolant gauge reaches the first notch on left, the 1st speed cooling fan should kick on. 2nd speed kicks on before halfway mark. 3rd speed past halfway, and sounds like a jet engine.

The 3 prong Temp Sensor is located below the lower coolant hose on the radiator. Since the car has set for 8 yrs...the sensor connector, wires, and sensor may all be bad.

Good luck finding an ol' school mechanic. In the meantime, read up on your 100 at this site www.sjmautotechnik.com in the troubleshooting section.

one5k

ur radiator is probably plugged. mine is and its doing the same thing. the reason they quoted u something basic in the dealer is no one wants to get involved with an old car like that and they could smell someone who was unwilling to pay a mile away. thats the way it works. unless you seem committed to spending the money and time they will blow you off. sorry, just the way it is. they start with the basics on a car with no service history. they have bigger problems than ur old car.

Old_Mil

Thanks, so (1) How would you diagnose this and (2) Aside from a new radiator, what would be the cure?

The other thing I've noticed is that when this car was new(er) on hot days after shut down the radiator cooling fans would run for a while. Now, I never hear them after the car is turned off. I'm wondering if there's a sensor of some kind that has failed, keeping these fans from running, and resulting in my warm running car.