os993

Very interesting - when I start the car (cold), oil pressure gauge jumps up to 4, then settles to 2-3 when the engine is warmed up. Never did this in the past - car would start cold around 2-3.

List of events: Did a DIY oil change (both filters) with Mobil One 15-50, Filters hand tightened. Bonehead move (had a cold) and forgot to drain the engine case oil. Figured it out three days later and re-did the entire job (draining both plugs + fresh filters). Interesting that oil pressure was "normal" after overfilled oil change, but changed after second oil change. I don't think I screwed anything up ( I hope not). Did I?

What could be going on? Will disconnecting the battery help?

Car's driving great, bty...

Appreciate anyone's assistance here - TIA

Robin 993DX

Oleg,

I don't think there is anything wrong, during cold start my engine oil pressure is also high at about 4 and then drops down it's been like that since day one.

os993

Thanks Robin. It's just so strange that this never happened in the past, even in the cold (that's SF Bay Area cold, so not very cold).

I disconnected the battery, but naturally this didn't do anything (process of elimination).

I even double-checked both filter tightness (made sure they weren't too tight).

Hmmm

os993

Actually, one more question Robin - did I screw anything up when I ran the car for three days (not much mileage) with the "extra" oil (forgot to drain the engine case oil & added 9 1/2 qts)?

TIA again!

Robin 993DX

If you didn't see any spilled oil out of the oil filler neck, I doubt it would cause any mechanical damage.

Jeff 993TT

Hey Oleg... I've noticed this same high(er) pressure after an oil change. It's gone away after a few weeks however.

os993

Hi Jeff, thanks for the feedback - so far, still high when starting and drops accordlingly...no big deal, but still pretty strange.

Lets say for argument sake that some oil did spill out of the oil filler neck, what exact mechanical damage could have incurred?

I just assumed that overfilled spilled oil would just cause more of a messy issue than a damaging mechanically issue.

TIA

hughfi

Its my understanding that when you put new clean oil in your car and fill it up, the pressure should be high when cold.

That makes complete sense as the oil is much more dense cold and hense produces stronger pressures in the engine housing. This is exactly what happens to mine. When full it goes up to 4 or even 4.5 if below freezing.

Once the oil warms up, it correctly drops down below half way.

One reason it did not happen before could be to do with either the type of oil in your car previously (was it 15-50?) or how old the oil was.

When oil has been used for some time, especially non synthetic oil, it is much more compressible than before hence produces much lower pressures even when cold.

The same happens on piston aircraft engines as they are flat also and work in a similar way.

H.

Steve Weiner-Rennsport Systems

Hi Oleg:

What you are seeing is normal and nothing to worry about.

Oil loses a bit of viscosity over time and the longer you leave it, the thinner it gets at high temps. You did not mention your oil change intervals but if the old oil was in there for 3K+ miles, its simply not as thick as when its new.

Over time heat affects all oils, even the synthetic ones and these wide range multi-grade oils do not get as thick after they have sustained higher oil temperatures over time.

Remember, your oil temp guage only shows that value at one point in the engine; its a lot hotter at the rings, bearings and camshafts,.... This is why its so important to monitor and contain oil temps in hot weather since you cannot truly see the real peak temps inside the engine.

Jay Gratton

Greetings,
I am going to say the same thing as a few of the others said as well. I to have noticed my oil pressure is higher at first too. Best of luck to you! - Jay Gratton