88 Audi 100 1.8E oil light flicker at hot idle

Two years ago i bought a dirt cheap, well used Audi 100 1.8E
this is the absolutely cheapest version of the car, with a 4 cylinder 90 Hp K-jetronic engine,
no power steering, no electric windows, no nothing.
basically a Golf in a larger piece of metal.
When I bought it it had 295000 km on the meter, and now it has 346000 (i drive a lot...). It has been runnig like clockwork all this time (and according to the previous owner since new), getting good gas mileage, no oil consumption to speak of (for an old car :) and only needed very basic maintenance (brake pads etc).
As I was driving to my folks for Christmas , about 400 km, after halfway it lit the oil pressure light, so I pulled over. when I checked the stick there was oil on it, but it seemed very thin, and it was on the low end of the scale, so I added about a litre, started the car and the light went off.
I wasa little surpirsed because unitl now the car hasn't used much oil, it basically needs a litre every other refuelling (1500 km or so, i usually top it up on payday and the drive a month; I get about 7.5 l/100km mileage), but this time it had used a litre in only 200 km. there is no obvious leakage, and no visible blue exhaust.
i got to my parent's house, celebrated christmas and went home (400 km)
The day after coming home I discovered that the oil light flickers at idle, whenever the engine is warm. The temp seems normal and the radiator fan turns off and on just fine. The oil level is at max. I feel no difference in the engine performance, it's the same smooth sluggish sewingmachine motor as always.
Do you people think I damaged the engine badly when I ran it out of oil?
I stopped the engine ASAP when the light came on, but I was doing 140km at 7/8 part throttle when it happened..
Maybe I just need an oilchange, to my layman eyes the oil on the stick seems very thin, compared to the oil in the bottle. Is it possible that short trips to and from work with repeated cold starts have made the oil mix with unburned petrol and such now that winter has come around, and then the petrol Oozed away when I took a longer trip and things heated up properly?
maybe 346000 km is about the life expectancy of the 1.8E 90 hp engine, and it is going to die anyway?
Maybe the short lack of oil pressure caused just enough wear to drop the idle pressure enough to trigger the sensor, and it was low already due to normal wear?
What do you people think? Any suggestions are welcome. This car has been a great cheapskate for me, I bought it for about 1000 Euro, and have done almost 50000 kms on it wiht only changing front brakepads and rotors, getting new tyres, a fanbelt and a set of sparkplugs.. incredible.
Hmm. i just realised i havent changed oil in 50000 km :-/ I guess I'll go ahead and do that tomorrow.
should i get a thicker oil for my worn engine? Should I even consider semi-synthetic or is anything but dirtcheap wholesale oil a waste?
writing to newgroups really help sometimes :-)
//Cheapskate Audi driver
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Hi!
Ronny Svedman wrote:

Nope. The "cheapest"[1] was the first from 82/83 with a 75hp (70hp Swiss version) 1.8l 4cyl carburated version...:)

Running at the minimum mark should never damage the engine (if that's your only problem). I numerously ran "out of oil" (dry dipstick), never had a problem with such an engine (DR) and sold it with 390tkm. Bone dry and as fast as from the factory...

+
The Audi has a two step "trigger" 1.8bar for above 2000rpm and 0.3bar for below. A few seconds below 1.8 and above 1bar at (140km/h>3000rpm) should not damage anything but...

Def'ntly. Esp. when I read:

+
+
100% yes. Thats 99% the reason you burn oil at all on the "first" longer trip among a lot of short ones.

No. See above.

Maybe, but only if the oil consumption raises from "immeasurable" between changes to "recongnisable". (You did not give WHAT oil you use at the moment.)

I ran semi 10W-40 from Walmart for years and it worked ok. And my change intervals were around 50-60tkm too. YMMV. When the oil is not used and not topped up (since there is no need to), then with a slightly better oil, you will sleep better when regularly apply change intervals in the 50thousands...;)
HTH So long! Ero.
P.S. [1] "Cheap" is relative...;) that one used 6.5l/100km in summer and 7.5 in winter...
--
Ero Rademer ANTISPAM in effect.

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On Fri, 2 Jan 2004 snipped-for-privacy@nexgo.de wrote:

Must have been the cheapest in 1988 anyway =)
Argh! that's gotta be a slug..

That is useful info.

1 litre oil to 150 litres petroll.. that has to be "recognisable" already :)
that poor little engine sure has a hard life in the heavy car.. lots of revving and full throttle accelerations.

I guess i'll go for 15w50 then, I whip the shit out of the engine way too often, it's just too small for the big car body...
amazingly enough the lifters are silent after just a few seconds on a cold start, not at all like other audis i've seen, thats why I was surprised to see it has low oil pressure. Maybe i should get an oil press. gauge so I can see whats happening.. Could be the sensor has stuck in "high" mode or something.
By the way: I hear a "bearing" kind of rattle at idle, that goes away when I press the clutch.. is that the clutch bearing, and how loud does it get before seizing up and wrecking things around it?
What is the best way to raise the idle RPM easily, to keep the oil light from coming on? a 50 or 100 RPM increase is enough to put it out. (and if i light the highbeams (2x60 + 3x55 Watt) the rpms drop a little, making the oil light steady instead of flickering)
Is the tiny stopscrew on the throttle valve arm the right place, or is there some other place to look?
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A heavier weight oil can help *if* the problem is loosening tolerances in the engine.

Low viscosity oil helps the lifters pump up faster. As for the actual pressure, a test might help, but it can be equally easy, as well as cheaper, to simply change the sensor switch. These things are dirt cheap (<$10) and are notorious for failing.

It's the clutch *throwout* bearing. Goes away when you press the clutch because you're exerting pressure on it. When it fails, it is more likely to fall apart and simply lie there - while you can't disengage the clutch. Not a terrible problem if you can start the car in gear and drive home clutchless.

Try the switch first. If it isn't that, chances are your oil pump is getting worn out. -- C.R. Krieger (Been there; done that)
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On Mon, 5 Jan 2004, C.R. Krieger wrote:

There is a slight but unignorable, ominous, knocking sound at idle :-( it goes away if i raise the idle RPM a little (so does the oil light).
I fear the main crank bearings might be worn out.. or the oil pump, as you said.

will do that.

okidoky. that probably means it will get a lot louder before failing. great =)

I kind of wonder.. What would happen if for some reason the oil filter would clog up with goop? would that drop oil pressure because of restricted flow or would it "just" mean the all the oil would bypass the filter via some pressure valve? (and circulate unfiltered..)
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Try 20W-50. With that kind of mileage... be happy. May be the oil pump failing or just too much wear on bearings. If the oil light came one while driving, that is not good. At idle not that much can happen.

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Hello ive had the same problem with a mazda 626, and it was the oil pressure sensor, i replaced it, and have not seen the lamp light after the replacement.
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On Sat, 28 Feb 2004 16:17:25 -0600, "sick_dog"
Hi,
I can't see the original message, but looking at the subject I would say I probably had a similar problem on my Audi 100 with 2.2l 5cyl engine (ocassional oil waring at revs above ~3000) and it wrecked the engine because I trusted the mechanic who told me that it would most likely be a sensor fault or an electronics problem :-(
Make sure you don't wait too long before you replace the sensor or find a garage which can measure the pressure.
Christoph
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