I'm a gauge watcher while driving....and I've noticed that the oil pressure gauge usually runs in the middle between the 4 and 5....but when you come up to a stop, it quickly drops to the 1.5 position. I was wondering if you folks see the pressure drop that quickly as you slow down. Since the oil viscosity is the synthetic Mobil 0-40, it is probable that when it heats up and the viscosity becomes more liquid, it drops oil pressure quickly, but it also goes back up just as quickly. I also get a bit of a hiccup when running slower and the pressure is sitting around 3.5-4. It will dip down then quickly go back up. I'm thinking a hiccup might be an indicator of a potential oil sensor issue.

I guess if the gauge is showing 4.5 while running hard and 1.5 when idling, that should be within specs even though it drops and goes up quickly??

 

bringing this back from the grave cause I have the same Q about the hiccups at a stop or while slowing down

 

nobody? ive searched with no concrete answer.

 

It's perfectly normal. With the engine at work temperature, the oil pressure depends on rpm.
At idle you will see something between 1 and 2 bar, and about 4-5 bar at 3000-3500 rpms.

 

As for the pressure going a bit down and then quickly up again, mine too does it.

 

+1, Correct and perfectly normal.

Keep fresh oil and filters in your car as well

 

I questioned the same thing, my mechanic said it's normal, rule of thumb generally is rpm's run up every thousand and the gauge pressure runs up etc. Guess its good to know so when you get on it and the gauge doesn't go up then "Houston we have a problem"

 

Normal.

Engine oil pump driven directly by engine and its output, max is 60 (or a bit more) liters per minute and is dependent upon engine speed. There is very little residual oil pressure. Once engine speed drops oil pressure folllows almost immediately.

My 03 at idle, hot (engine up to operating temp) idles around 1.5 bar with Mobil 1 0w-40, a bit higher, call it 1.75 bar, with Mobil 1 5w-50. With 10w-40 about the same -- probably couldn't tell the diff -- as Mobil 1 0w-40.

At 3K rpm oil pressure at 4.5 bar maybe a bit higher with Mobil 1 5w-50 oil.

What I do see is when car crusing at say 2K rpms -- using cruise control so there's no chance my right foot playing a role in this -- is the oil pressure needle will drop suddenly between a half bar to a full bar and then just as quickly come right back up.

I can't remember the oil pressure in effect at 2K rpms though I do know the oil pressure is good, reasonable, but the needle does move down and up again.

I assume something in the gage hardware cause I believe oil pressure good at all times and I've never seen a warning light. Honestly, if I suspected any real drop in oil pressure I'd have car in shop right now.

Sincerely,

Macster.

 

The oil pressure sensor is notorious for causing "blips" in the oil pressure gauge. Mine will drop to zero for a moment for no good reason and then work properly for weeks before it occurs again - going to replace it this winter. A good rule of thumb is to replace it every five years - same goes for 993/964 models - they use the same sensor I think.

 

had mine replaced, works like a charm now

there is a diy thread on here or rennlist that show you how to do it in 45mins

 

Taking car in Monday for some vibration probably due to mild tire imbalance. Since car under CPO warranty I'll ask about having oil pressure sender replaced while car at dealer service.

Sincerely,

Macster.

 

your sender works normally...Oil pressure is rpm related,because oil pump is mechanically chain driven from crankshaft...so rpm of oil pump are related to rpm of engine...it idle,when hot you should see 1,5 to 1,8bar with 0-40 oil...when revs go up you should see values up to 5bar...(actually oil pump can pressure oil much more but there is a release valve rated at 5,5bar so to avoid breaking oil lines from overpressure...)However it is very common fo rour engines to have failures in oil pressure sending unit...if you see at idle values close or below 1bar go ahead and replace sending unit for oil pressure...its the same for carreras and turbos and all fail...when i replaced mine i doublechecked pressure with a mechanical unit mounted on senders bolt...i found that actual values were about half bar higher than gauge values...so when i see 1,7bar at idle actually i have 2,2bar...

 

Regarding Macsters 12/5 post with oil pressure dropping .5 bar when accelerating from ~2000 rpm, I noticed the same on my '02 and asked the local Porsche tech. Response was this is normal with the variocam plus kicking in.