Hi all. I'm obviously new. I bought a used 1993 Audi 100S with 164K miles. I really don't know much about its previous service record except that the tranny has been recently done. It seems to run great. However, I noticed that the oil pressure gauge is topped out when running level and steady. When I stop hard or turn hard (anything that changes the car's attitude) it drops precipitously, sometimes to almost 0. It then recovers with idle or even faster with accelleration. I'm ashamed to say that I haven't even checked the oil level yet but I'm going to. Is this an indication of a bad pump or merely a low level?

In addition, when I first got the car, it had been sitting. During a 30 minute drive, with hard accelleration, there was some blue smoke out the tailpipe. That has stopped. No further smoke and no real perceived loss of power.

Thanks. Any help is appreciated. I've also heard that I should get the timing belt done since I don't know if it has been done, so I'll have this in the shop soon for that repair and would love to know more about the oil system before the whole thing's apart and costing me more than it's worth.

-Jamey[sm=dontgetit.gif][sm=dontgetit.gif][sm=dontgetit.gif]

 

The pegged meter is normal when the oil is cold, gradually it should drop as you drive. The electrical connectors on the oil pressure sender are prone to oxidization and are not showing the correct pressure. I had this on my 4K as well as my 100Q. The sender is also prone to failure. If you unplug the sender the gauge will peg the scale. If the oil level is low you will get oil starvation but I think that you should also get an oil pressure warning light on your dash. I had this happen on my 4000S before I rebuilt the engine to solve the oil burning problem. I think that the rings and or valve seals are going or are gone. An engine with 164K probably needs at least to have the valve seals replaced.

 

Thanks. I'll look into having the seals done when the belt is done.

 

My 90 200 has wierd problems like that, too. It's usually pegged. but once in a while it'll drop to just below pegged and the oil warning light will come on on the display. This happened once about three hours after I changed the oil. I figured it was just a bad sensor or something, since i'm not burning or leaking any.

 

The oil pump on the 10-V 2.3 is quite well made, mine had little wear after 155K. During an oil change I prime my filter so there is less air in the system. If you have doubts about your oiling system get a cheap mechanical oil pressure gauge to verify the performance of the gauge. I ran mine temporarily under the hood and through the side window, after I was satisfied with the results I put the original sender back in and reconnected everything. Audi's have a complex electrical system and after a few years they are prone to failure mainly a result of oxidation on contacts. The Audi dash is far from reliable and is quite notorious for intermittent failures. There is a service bulletin to correct this problem.

 

Welcome to the forum Thissell!

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