Dear all,

I know there has been several posts about this, but most of them for idle times...

So please help me with this, I have a porsche carrera 2002 model, and this is the problem:

Setting: After long times of driving, mountain road, during the climb, the temperature would usually reach 190-200, which i think is normal, right? My speed usually doesn't go above 110 Km/h, slow for a porsche...

Parameters: RPM, normal...oil 1.5/1000 rpm, ambient temperature 25 C, oil level manually tested before ride maximum mark, very new oil 10W-40 TOTAL...

Problem: At the end of the 1hour 50minutes journey, total loss of oil pressure and car turned off. There has been 2 warning signs before that where i would lose oil pressure, but as soon as i floor the fuel pedal the car recuperates.
I don't know if removing your foot off the gas is considered idling in this case, but its usually what you would have to do when a car is in your way ...this is the 2nd time this happens at the same area, can it be the altitude? (>2000 meters high)

I'm forming a testing strategy because i will not leave it up to the mechanics who already nearly destroyed my engine twice by their unprofessionalism. So my strategy goes in the following sequence:
- Test oil filter, even though its a new OEM part that i recently changed, but i need to know what to look for exactly.
- Pressure relief valve (even though i think this should cause oil loss pressure everytime i go for a climb, not only when i drive upwards for more than 40 minutes)
- Gauges

Any feedback is well appreciated, especially if i missed another point...

On another front, does everyone have on their car manuals that the porsche needs 8.5 liters of oil?

Thank you a lot...and great forum btw, helped me a lot with the classic porsche overfill

Best Regards,
Elie

 

You will have to elaborate on total loss of oil pressure and car turned off part.

How do you know that you completely lost the oil pressure? What warnings popped up? Did engine cut off on its own?

If you really lost oil pressure and engine stopped, usually that means you already caused terminal damage to your motor and engine is ruined.

 

It may be that your described circumstances are coincidental to the classic oil pressure sensor failure, and e.g. the recuperation you refer to is the bounce back that happens in that state. Obviously it needs sorted out before you run the engine when there is insufficient pressure read.

 

The engine is not losing oil pressure or the symptoms would be quite different.

The sensor/sending unit is probably bad but you can check the connection in case it is loose or there's corrosion.

 

I disagree here Macster. I would also say "sensor is acting up", if not for the part of his engine shutting off on its own. When sensor goes bad, you don't get the engine shut down. You get the the "oil sensor died" message on the dash, needle for oil pressure drops to zero, and you continue driving along.

 

Yeah - depends what you mean by "car shuts off" - engine dies ?
When the sensor is going bad the needle on the dash will drop to zero pressure and you will get a warning message coming on in the display - then needle will randomly bounce back to 5 bar ...common issue ...

 

To be absolutely sure, attach an external oil pressure guage to the motor to make sure there is really no oil pressure problem. Pretty unlikely, but better to be sure than sorry.

Then, replace the oil pressure relief valve with the updated version if you haven't already, and then replace the sending unit.

Probaly overkill, but I don't mess about with oil pressure.

 

I think you have an idling issue when the engine is hot and not an oil pressure issue.

 

If the sensor/sender is bad and sends a too low of oil pressure signal to the DME the DME could I guess turn off the engine.

It is very rare for an engine to just lose oil pressure. In the case of the Porsche engine the IMS has to stop turning or a pressure relief valve has to stick open or the engine possibly develops a huge internal oil leak. And it is rarer still for one to lose oil pressure and not suffer serious internal engine damage that upon restart of the engine, if the engine would even restart, to not make itself known.

But I take your point, and would add to be safe the OP should avoid running the engine and get the car flat bedded to a shop for diagnosis and repair. An oil sensor/sending unit R&R is not a big deal but the though while rare but not impossible loss of oil pressure should be checked out and the engine and its oiling system given a clean bill of health.

 

More clarification is needed from the OP regarding engine shut down by itself.

When my pressure senders went bad, the DME didn't even try to shut down the engine. Car just drives normal, like everyone else. The pressure goes to zero momentarily but then recovers. I've gone through 3 sensors in 60k miles and every one of of them failed the same way.

 

The total loss of oil pressure was the message i got on the front screen. The engine started sort of knocking for a few seconds, then shut off automatically...Previously the engine would knock a little, with the loss of oil pressure message appearing, but then everything goes back normal again when i put my foot back on the fuel pedal.

I tested the oil today, still at maximum level, clean oil (no contaminants and probably no fuel as well)...Engine performed well today, but i didn't climb with it, oil pressure normal i would say...

For Imo000, idling issure not oil pressure issue? so probably i should be able to test that even when the engine has not been running for very long...

So i guess manual testing oil pressure is the best solution to begin with, time to look for some new mechanic...

Do i really need to worry if the engine turns back on normally?

Thank you all for your feedback, much appreciated...

 

Elie, at this point I would tow it to the mechanic and have them take off the oil pan and inspect the oil pump for any blockage and for proper operation. Also have them check oil filter for any metal shavings.

Knocking and shutting off is definitely not normal. Your situation does not sounds like a simple sensor failure. This is the sensor failure message FYI.

 

Sounds like your bearings are shot. Knocking noises are true signs of no oil pressure. As someone else mentioned remove the oil sump pan bc there is going to be oil shavings in there. Youre either going to need a rebuild or find a used engine.

 

off to the mechanic then...but just for info i might have described knocking wrong?...i don't really hear knocking, the engine shakes for a moment before turning off...is it the same?

 

Just a WAG......I had a cam actuater go bad one time. Car stumbled at idle and oil pressure was very low but cleared up at higher RPM's. I had a CEL too but it was not flashing. The code I had if I remember right was 1304. My car also shook like you describe.