Haunted Oil Warning Light

courtesy of Bob, The Auto Answer Man

I have an intermittent problem that's driving me crazy. I have a 1984 Audi 4000, a wonderful car. But the "oil warning" light (and obnoxious buzzer) comes on every now and then, for no apparent reason. We check and change the oil/filter periodically, and the oil level is never low or anything. There is an oil pressure gauge, and at the times when the warning light goes on, the gauge is usually pinned as high up as it will go.... normal for that gauge would be about 3/4 of the way up (though it fluctuates). I've had a dealer check it over more than once, but they haven't been able to solve the problem. There isn't any rhyme or reason to when it comes on. The constant thing is that on those days when it decides to do this, the light comes on whenever I go above 48 mph. Always right at that point. As soon as I slow back down, it goes away. Weird!

What I would like to do is just unplug whatever wire is leading to the warning buzzer! There certainly doesn't seem to be anything wrong with the car, so I'm assuming that there's something wrong with the warning light instead. How can I figure out which wire it is? And would that be a reasonable solution?

So you are saying that the light and buzzer come on when there is too much pressure? That is odd. They usually come on when there is too little pressure. If that is the case, the pressure going to the max when you accelerate, that is kinda normal but not to the extent that you are saying. There might be a slight plug in the pressure relief valve in the oil pump. But since it is intermittent, maybe there is an electrical problem and the reading is false. What I recommend you do, is have your mechanic install a mechanical gauge. This gauge will have a little hose that actually has oil flowing through it. This will tell you what the pressure is and not have to worry about anything electrical. Now, you can see when the buzzer goes off, what the pressure on the other gauge is. If they do not match, then one of 2 possibilities. 1: electrical problem feeding the electronic gauge or the sensor 2: the place where the mechanical gauge is reading is actually at a lower pressure. This would indicate that there is a blockage somewhere and this should be fixed!
Good Luck!
Drive Safely!
Bob, The Auto Answer Man

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