Dal Heger

If you read the rest of the thread you'll notice that he says that he has great oil pressure and that the oil pressure light goes off as it should and that the pressure gauge reads between 4 and 5 bar on the scale, therefore it IS NOT OIL PRESSURE RELATED.

The oil LEVEL light has NOTHING to do with the oil pressure circuit. He is 1/2 quart low on the oil level, or the oil level float (sender) is bad.

Dal.

VWaddict

Ah yes, I did miss that. It's his 4th or 5th post, information not supplied earlier.

I reckon a bad oil level sender. If he's at the top of the dipstick, I wouldn't add oil, since with many cars this can damage the catalytic converter.

Keith

Dal Heger

I'd still say add a little bit of oil. These cars can easily run with the oil level a little bit above the full mark. In any case it would test to see if the sender is working properly or not. The sender is a very simple little float arrangement. I would doubt that it failed. I'd double check wiring to the sender unit. I'll double check if it makes the circuit when it's full or when it's low.

Dal.

peterr

I don't want to discourage you from tracking down this problem, as anything that causes oil starvation can be catastrophic. If your oil pressure pegs or drops be very cautious.

On my S2 the oil LEVEL light came on at 1/2 quart low when the dipstick level was midway between the full and empty mark. After it came on it took some driving with a full level to get it off. It was unnerving but it did get me in the habit of checking my oil level about twice a week. Its actually pretty easy to drop 1/2 quart low, especially in a porsche in warm weather.

I have never seen the oil level on my 944S or 951 come on. I believe if I got down a little over 1 quart they would, but neither of those consumed any oil, or perhaps more accuratley never got near consuming 1/2 a quart between oil changes.

Last time i checked the STP filters were made by Champion Labs, who also make the Bosch Filters sold in North America. At times, the Porsche branded filters sold here have been Bosch, so it would not exactly astonish me if the STP is the same filter. Any brand could have a bad individual filter, so you may still want to swap. Like one of the other posters I buy my Mahle Filters online from Paragon or Pelican in lots of 4 or whenever i am ordering some other part. Last time I paid about $5.50 per filter. In canada this filter wholesales for about $13 so I feel good. Especially after local stores are charging $32 CDN for the Porsche (Bosch) and $34 CDN for the Fram (crap).

I know that most euro performance engines like a heavier oil, and I have run Castrol GTX 20w50 in summer in my previous cars, but I am coming around to the idea that a good 40 weight synthetic (5w40, 0w40) is better in all ranges. I really do not think that our cars need a 50 weight oil and the startup viscosity of a 20w50 can't really be good for the car. There are so many great Xw40 synthetic oils on the market now. Lots of cars are running 5w20 oils now. While I don't think they are a first choice for our cars the trend is thinner. I do know people running 5w20 in Ferraris specced for 60 weight Shell Helix, though.

Almost any brand of API SM certified oil sold these days is head and shoulders above what was available when our cars were built. Even if you want to run Dino oil the 15w40 HDEOs are a great choice and often a cheaper, better alternative to 20w50.

Today you can take your pick of lots of great choices. Not to dis Valvoline, but generally most of the tribology folks I know consider Valvoline at the bottom of the pack of major oils. Not a terrible oil by any means, just a very run of the mill oil at a premium price.

Ty

Thanks for all the replies. I use to have Mobil 10w-30 in the oil pan, but since the summer is approaching I decided to switch to (manuals reccomendation) 20w-50 for our 95+ degree weather we have here. I noticed that none of you had problems with the 20w-50 before so I'm guessing that's not the problem. I checked to see if the float sender wire was hooked up and it was. Does anyone know how to check the float sender unit to see if it's working properly?

jacklet

yeah take it apart, its just a simple sender but unless you take it off you have no clue if the float is good or bad-i removed mine and made a plate up for a return line from my catch can-similar to what Tony G did

Ty

Do I have to drain the oil before I check the sender and are there any special tools that I'll need? I'm assuming the unit we're talking about is the one on the passenger side of the oil pan with the round metal prong sticking out of the oil pan. Is this correct?

Dal Heger

Yes, you will have to drain the oil to get it out, or you'll drain the oil when you remove the sender (it's under the oil level normally). Get a new gasket for the sender from Porsche. Other than that, it's a really simple little float that sticks into the middle of the oil pan. Three bolts and it's out. I'd personally just wait and live with it until you need to change the oil. Do it then. As long as you're checking your oil level via dipstick everything should be ok. You can also try disconnecting the oil level sender wire to see if it turns off.

Dal.

Ty

I changed the oil and the filter and the light still comes on, but not as quick. As long as the engine is idleing the light does not come on. When I rev the engine to 4000 rpm the light comes on. I started to remove the oil level sender, but just wanted to see if the oil light would go off by itself. Also I switched back to mobil one 0-40w synthetic, hoping this would relieve the problem as posted by another member but no dice. I hate driving the car with the low engine oil light on not knowing if the oil level sender is bad or if there's another problem lurking to bring disaster such as a new engine! I will check and or change the oil level sender unit to see if that's the culprit. I'll keep you guys and gals posted.

Racer46

Ad an extra 1/2 quart of oil and see if the light stays out. When you rev the engine more oil is pumped up to the top end and the level will drop.

luckett

How can this damage the cat?

WesM951

I've been using 20w-50 Castrol Syntech blend with the STP Filter and no issues here. I'm ordering a bunch of Mahle ones from paragon for the next round of changes.

Ty

How many quarts are you guys putting in the crank case with a filter change. I put in 7 1/2 and the dip stick is showing a little over the top mark. Do you think I should add the other 1/2? I read where I might mess up the catalytic converter in a previous post by over filling, but is that true?

Ty

Remember that I have a 88 944 turbo.

Dal Heger

There are three separate circuits for the oil warning system.
1) oil pressure gauge - this gives you the indication of how much pressure you have in the system
2) oil pressure switch - this switch closes when you are under 1 bar pressure and lights the warning light on the oil pressure gauge and the big <!> light to get your attention to turn the car off NOW.
3) on 87+ cars there is a totally separate oil LEVEL float in the sump. This switch closes when it reads 1/2 quart low (out of 7.5 quarts) IN THE SUMP. IT HAS NOTHING TO DO WITH OIL PRESSURE!

The third light is what is coming on. As it only comes on when the car is 1/2 quart low it means that the car is 1/2 quart low, or that wiring (which it TOTALLY separate from the oil pressure wires - which also carry redundant warnings and circuit paths) is to blame. Hence my suggestion that he add 1/2 quart of oil and see if it goes off. The dipstick is not an accurate measure, the float is.

Revving the engine should have nothing to do with your oil level light unless you have a problem with the oil draining back from the head (which you shouldn't since there are 4 big oil drain passages there.
Did you have any head work done recently? If so, did they put back the oil pressure restrictor in the head? If they didn't then that would cause the problem you're talking about. There would be a LOT of oil heading to the head and pumping a bit of the sump low enough to trigger the level warning light before it drains back from the head.

Otherwise I have no idea

7.5 quarts is usually right for an oil change.

Dal.

P.S.

If this is a new engine then talk to your head guys or the guy that built the engine, they didn't put the restrictor back in the head.

P.P.S.

Yes, Keith is correct in that an over full oil level will over time damage the cat. How? The oil burbs into the engine via the crankcase vent system, gets partially burned, and most makes it to the cat, coating it and causing it to quickly fail. It can also burn in the cat, causing it to go over temperature and melting the metal matrix, causing it to collapse and clog the cat - and ruin your horsepower and torque.