marka09

42K miles (yes, original), oil level is at the top mark, when the car starts the oil light goes off, excellent oil pressure (4-5 bars) but as soon as I move the car the light begins to flash. The manual says that it is indicating the oil level is low but it's not. I'm suspecting a dirty or bad oil level switch if there is one. Any ideas? If there is a switch where is it located. I have to change the thermostat and antifreeze sometime this week so I'll have the car raised anyway - perfect time to replace the switch if I can.

Thanks,
Mark

Yarf

There is a oil level sensor installed in the passengers side of the oil pan.
There is a press on connector that may need cleaning, the wiring or the float based sensor is not functioning correctly. The sensor is expensive.
http://www.pelicanparts.com/cgi-bin/...9%29%2C%20Each

marka09

Thanks! I'll check it. I'm thinking that if I remove it but leave it wired in, I can raise or lower the sensor to see if the light goes out. (key on but not running).

If it's a bad level sensor I may just disconnect it. I check my oil level frequently and change it often.

So I guess it will be an oil change, antifreeze change, and thermostat change all in one.

Yarf

If you remove the connector and ground the contact in the connector the oil low light will remain off, assuming that the wiring is good.

John_AZ

Mark.

'88 924S 63K original! OK you win

Mine will flash too if I start it and immediately stop the engine after a minute or so. It will also flash if I drive a short distance and need to park with the front of the car up on an small incline. Both annoying examples.

I solve the problem by understanding these 2 potential causes and stop making these mistakes.

Keep the oil filled to the top of the dip stick.

BTW---over the years I have found that the blinking light wiring is connected to the -------------brake master cylinder reservoir cap with the 2 wires ---low fluid indicator. It may be your problem to fill the reservoir to the top "full" mark.

Now it only happens if I forget and do the first two examples.......

Oh, I bought mine in Nov. '95 with 39K miles.

GL
John

ernie9468

Hum!!!63k miles -39k miles=24k miles____ 2011-1995=16 years, do you ever drive the car & when,no wonder the oil indicator is flashing , lol the car is so happy when you start it up that it has to let you know it's running.By the way sunny here today but cold just dig ourselve from under 4' of snow,wish I could open the garage door & let her run a while but it's coming,another month I guest I'll be giving it driveway run,take care John & go for a spin for me in your's .

marka09

I bought it in 1990 with 24K on it, so you can see that I drive it a lot. I also have a 911SC 1980 Weissach Edition that has 76K original miles.

I'll try grounding the wire coming from the sensor when the light is flashing (the light that looks like an old time oil filling can - yes, I remember using them to fil the oil with recycled oil) to see if it shuts off. I have filled the brake fluid to the max mark and the light didn't stop flashing. The weird part is that it doesn't flash until I move the car - even a couple of feet will make it come on. Since the flashing light means low oil level and my oil pressure is typically between 3 and 5 bars, I am thinking that it's the sensor and not a real problem.

So at this point my list is growing... test the sensor, Antifreeze change, thermostat change, oil change, and brake fluid change. No longer a small job.

marka09

Okay - this make no sense. I start the car, not flashing light. I disconnect the wire to the oil level sensor and the light flashes. I ground that wire and the light continues to flash. Is there something I am missing? I thought that grounding that wire is the same as having the sensor say there is enough oil and that it should shut off the light. HELP!!! I wish I had a wiring diagram for this car. I just don't understand.

John_AZ

Did you clean the brake MC reservoir cap contacts?

and as a bonus..
As well and having some excellent DIYs and info, TexasBlake has a complete "document" section you should view...
http://www.texasblake.com/porsche/

GL
John

marka09

Hi John, Yes, cleaned the brake fluid sensor terminals. I tested the function of the Brake Fluid switch and it works fine. What has me confused is that the wiring diagram (thanks for the link) indicates 2 wires on the Oil Level Sensor (Br and wt/ye) when in fact there is only one wire YE on mine.

The other confusing part is that it comes on until the car starts (as it should), then turns off as it should. It will remain off until the car moves a few feet forward or backwards. I'm starting to think the DME has something to do with it because that would fit the logic of it also having the speedo sensor, etc connected.

For the time being I've removed the light behind the little picture of the oil can. My oil pressure is good and I just changed the oil and filter today so I know I have the correct amount of oil. Any reason I should be overly concerned without the light? Any thoughts on the DME? The wire connects to 8 on the DME according to the wiring diagram.

Does anyone know how the switch works? Is the voltage taken to ground when the light flashes or stops flashing. I metered the wire and there is 12 V there. Grounding it doesn't stop the light from flashing.

Yarf

You need to ground the wire and then start the car. The oil warning logic latches the low oil level warning, the engine needs to be shut off to clear this warning.

John_AZ

Mark,
In the WSM (Printed) Vol IV, electrical, Wiring Diagram type 924S Model 87 Sheet 3 (mine), there is only one wire from the "Oil Level Warning Switch" and it is black/yellow in color (WS/GE). Your '88 has the correct wiring.

I would go back to basics and clean every ground under the dash and engine.

You might just wiggle the DME computer connection & wires and see if anything changes. Be gentle. I would not do anything more. This could open up a "whole new can 'O worms".

GL
John

marka09

Yarf, Ahhh, why didn't I think of that, a latch circuit. I'll check that out - thanks!!!

John, Thanks for the clarification - I think I am going to need to buy a good manual.

I'm going to remove the sensor when I do the other work on the car and clean it. I'm thinking that the movement is causing it to lose contact and set the light on. I'll also gently wiggle the connectors at the DME. I've actually had it out in the past because the place where my car was serviced in Florida helped me map the 8 settings within it so we would know the best settings for different conditions.