J.A.Schulte

I changed the oil in my 1980 4000 yesterday and now my oil light won't go out. I wanted to try Mobil 1 in it so I flushed the engine first with Gunk engine flush. I idled the engine for 5 minutes per instructions, drained the oil out, put on a new Mann filter and added 3.5 quarts of oil. The light refuses to go out. Any ideas? Thanks!

Tom Chudzinski

Check the oil level on the dipstick. If ok, start the engine and quickly pull off the oil filler cap to see if you have oil flow to the camshaft. You should see fresh oil spraying around under the valve cover. If you see oil spraying, check the sending unit, wiring, gage, etc. If you don't see any oil, shut the engine off immediatly. You may have the flushing fluid (too thin) stalling out the oil pump or the pump/pickup is air locked.

Tom

Tom Serrago

Was the oil light on continuously before you started?

J.A.Schulte

The light wasn't on before or during the flushing process. Only after I rolled it off the ramps and started it after the oil change did the light refuse to go out. I'd never used the flush before.It seems to me the that maybe at the heart of the problem. I talked to other people who have used similer products with no ill effects. I tried to prime the pump through the oil temp sending unit hole with an oil can, but that didn't help. I pulled the oil light sending unit out and there wasn't any oil seeping out of the hole as it had when I pulled the one out of my Scirocco. Is it possible that the PO used an additive like Slick 50 and the flush removed so much of it that the pickup tube or the relief valve are clogged?

Tom Chudzinski

Again, Is there any oil spraying around in the inside the valve cover when the engine is running? Did the pump fill the new filter with oil, or is it dry? Check this to confirm if you have oil pressure or if its a sending unit/gage/wiring problem. If the pump is dry, it may take more than an oil can to prime it. If you have no flow from the tests above, try pulling the oil sending unit and applying vacuum for a few seconds. Don't get to crazy with the suction, you could damage gaskets or seals. That should suck oil up from the pan through the pump.

Tom

DaveN

your on the right track with a clog, or the pump is cavitating. I don't think you can prime the pump by putting a vaccum on the hole, not sure about Audi (never had to tear down one of those), but all the pumps I've had apart are gear, and if you tried to draw on them you would just pull the oil out of the remainder of the feed lines. I know it's not the news you want, but I suspect your going to be dropping the pan.

Tom

He didn't say it was _running_ when the sensor was out. I thought the vacuum trick might be worth a try. Probably safer than pressure down the dipstick tube or in the oil cap. Same idea but from a different direction. If the back flow prevention valve in the oil filter is working, that should seal off all the engine oil galleries forward of the filter leaving only the pump pick up open to atmospheric pressure. The oil only needs to rise about 4 inches from the pickup to prime the pump. Just my theory!FWIW I wish I had J.A.'s problem, tomorrow I pick up my 84 5KS with a new trans/final drive. Ouch!

Tom

J.A.Schulte

Tom,I did look in the valve cover while the car was running and didn't see any oil spraying going on. I did the same on my "84 Avant and there was oil spraying everywhere. My mechanic has access to a tool to turn the pump gears through the distributor hole in hopes of priming the pump. If that doesn't work, it looks like we'll have to drop the pan. Thanks for all the help!

Tom

Well, whatever it was that happened on that oil/change/flush, it's probably safe to assume, you did it. I guess that makes the responsibility of fixing it, yours. This is the mechanics nightmare. I'm sorry it didn't work out for you. Food for thought.

Tom

DaveN

I agree, pulling it while running would be bad, I remember my brother pulling a valve cover off of an engine with it running so he could check and see if oil was getting to the top of the engine. It was, my parents never did get the ceiling of their garage to stop bleeding oil.