Flying Finn

OK, here's the thing.

When I drive my car, oil pressure is reading pretty normal, about 4-4.5 but after maybe about half an hour it starts reading about 5 & even little more...

What could that be? Does anyone who has had similar symptoms? If I shut down the engine & start it again, it will only read about 4.5

Could it be that the sender is somehow 'stuck' or something and after a while with higher pressure it get free (I really don't how that thing works, so..).

Also, I read on one of Robin's earlier post that you need to drop down the engine in order to change that sender, is it really so?

I'm not gonna worry over this too much but I was thinking if it's easy to just change the sender, I'd do that. If it's hard (and no one tells me this is serious) I'm just gonna ignore it & start driving (even) harder, maybe that'll teach it (sender/gauge) a lesson!

Man, how could this end up being such long post!? Sorry about that folks.

Ray Calvo

Questions:
- what kind of crummy oil are you running
- when was the oil changed?
- what is oil temp doing? If temp is dropping when pressure is rising, is perfectly normal. Now, why is temp dropping (if it is) is another question; might be something in the oil cooler thermostat or the cooler fan. tehnagain, you might be hitting open road and getting mroe air thru the cooler. If oil temp doesn't change when pressure rises, then I'm stumped. Thought would be replace the oil and filters and see what happens.

When you shut off engine, you lose oil cooling. So briefly oil heats up. Mihgt be why pressure drops after restart.

I assume all this is at constant RPM? Because pressure rises with RPM!!!!!!

Flying Finn

Thanks Ray!

To answer your questions:

-Mobil 1 15w-50.
-Oil & filters were changed about month ago.
-Oil temp is normal, not doing anythin funny...

I don't think it's the heat, because yesterday I was stuck in a trafific for a moment, so the temp was at about 9 o'clock, still, the oil pressure was hitting 5.

And yes, rpm's are constant!

And this all is real, not something that I've looked gauge wrongly once etc. I've checked this two or three times.

GeoT3

Flynn,
I would check at what temp your oil thermostat opens at by feeling the pass. fender. at what engine temp your oil cooler fan comes on at. I am also wondering if the oil filter(s) is/are defective. Did this just start to happen after the oil change?

GeoT3

Flying Finn,
Sorry I botched your name.

Flying Finn

George,

My oil termostat open just about at 8 o'clock mark (which is normal I believe) I'm not sure about the fan.

But this is not so much related to the oil temperature, it does this even if the engine is warn, hot, or not so warm.

Does anyone have any information about the sender? Could it be 'stuck' or something? That's only thing that comes to my mind...

Don't worry about the name, I've been called worse that that

J-McDonald

I'm not about the causation of your problem, but I know that replacing the oil pressure sending unit on a 964 is a $300-400 job at the dealer (because you need to remove a bunch of stuff to get to it). The sending unit itself is about $20. 993's may be different.

Flying Finn

Yep, I've heard it's a PITA job to do & I'm not going to do it before I'm sure there's something wrong with it.