theykallmekem

i have a 1986 Porsche 944, and i have had it for a while now (for more backround information on myself, look for my lost key topic >_<) but anyway before i lost the key i noticed that the oil pressure meter has decreased. before, the meter would read above the 3-4 range. and recently, when i DID start it before, it would idle at that 3-4 range, but after it gets warm and a few revs, and driving slowly, it would go below 3, and be around the 2.5 and below sometimes....

i checked online and there are many different things that can cause low oil pressure. one simple one was to just change the oil and see if anything happens?? and another reason that is so severe is that the engine might need an engine overhaul because of the camshaft bearings.... O.o and another one said something about the timing chain?

my mechanic also suggested those but before i let him dig into anything, i just want to know a second opinion of what might be the problem? thank you !

LeMans71

I'm new to the 944, so I can't help with any specifics, but in general you're going to see low oil pressure for one (or more) of several reasons:
-Low oil volume (which can cause cavitation in the oil pump - i.e. pumping oil AND air - bad)
-Low viscosity (oil "worn out" or very hot)
-Problem with the pump (though generally oil pumps are positive displacement design, and therefore are either working satisfactorily, or not at all)
-Excessive clearances within the engine (generally at points of restriction, like the main, rod, and cam bearings - due to wear or failure)

I don't know if the gauge numbers you are seeing are low out of spec, but they do sound low. It is normal for pressure at idle to drop after the engine is running and the oil has heated up (lower viscosity). It would help to know some specifics - how many miles on the engine, what type of oil are you running, how old is it, etc. If your oil is "old" I would start by changing it - that's the cheapest thing to check first. If the engine is a high-miler, you could try one of the formulations for "high mileage engines" and see if that helps. If it does that's good, but then realize that the problem is probably worn bearings with clearances that are beginning to be excessive, and that a rebuild is in your future.

Jfrahm

You are posting in the 944S2 section, for the 89-91 944S2. You will get a lot more exposure if you post in the regular 944 section.

Jfrahm

PS there is no timing chain in a 944NA and no camshaft bearings in any 944, so you might need a better mechanic.

theykallmekem

O.o.... no timing chain OR camshaft bearings on a 944 ........ V_V.

well, that is not all of the mechanics fault. i just did some research on "low oil pressure" and just got a few explanations on it. although, i am not that surprised that the mechanic did not know that the 944 does not have those parts in it.

i do not believe there are any real Porsche enthusiasts or Porsche mechanics around here in my area anyways to get a real explanation on what is happening to my car. i really just love driving it and thats all i know about. i do have a lack of knowledge but thats why im here to learn and to ask but i do read some of the other topics and such but its still difficult.

i just again want to thank you for your advice i do appreciate it

theykallmekem

ooh and i forget to reply to the first reply to LeMans71:


thank you for your reply, and my 1986 Porsche 944 has 76,XXX original miles on it and i use 10W40 MOBILE oil... and i definantly need to do those trouble shooting tests and i will try to keep up to date ^_^ thank you

RSflared72e2

First things first: check the tightness of your front main crankshaft bolt. The oil pump is driven off of a friction fit here, and a loose bolt can drop your oil pressure.

In these cases, the bolt will seem apparently tight by hand, but a socket and torque wrench will reveal otherwise. Seen it on a few 944s.

What happens is the bolt ends up tigher than "hand tight" due to engine rotation vs. inertia and momentum of the bolt and pulley assembly, but not tight enough to maintain the needed friction fit, destabilizing the bolt.

I don't have the torque value on hand right now (I'm in Iraq!), but suffice it to say it goes on as tight as you can get it with a long breaker bar...check here or on Pelican for the correct value...make sure to use a quality flywheel lock when doing this work...

jstand22

10W-40 is too thin for summer in your area...switch to 20W-50 and I wouldn't be suprised if that's all your problem was.

rickb20

theykallmekem said, You do realize that the 944 has a timing BELT and that it's very important to make sure it's changed regularly. Old/worn timing belt = catastrophic engine failure

Search "timing belt" in any of the 944 forums for more details

theykallmekem

im sorry to reply late, but i have been out on holiday/vacation so i have not been able to get to a computer.

i have changed the oil to 10W-40, but 20W-50 ??!! the mechanic i see told me that is too thick and recommends 10W-40, and i use fully synthetic castrol. i will try that change soon thank you jstand22 for your insight.

i had a feeling it had a timing chain because like you said rickb20, old/worn timing belt = catastrophic engine failure. i saw an ebay listing with some dudes 944 waaaayyy back saying his timing chain snapped and his engine has ceased but is selling body. but that was a long time ago thats why i had some idea of the timing chain.


but what are the chances its the oil pump ?? it is a 22 year old car....

rickb20

Lemans71 already addressed your last question: -Problem with the pump (though generally oil pumps are positive displacement design, and therefore are either working satisfactorily, or not at all)

I don't know that I've heard of anyone on this list mention problems with the oil pump itself.

Are you sure you know how to read the oil pressure gauge and what is really normal?

theykallmekem

well, as for what is normal, for me, since ive been driving the car for almost 2 years, and my dad has owned the car and has had no problems with it for as long as he has owned it (but has not daily driven it, just occasionally) it would (before) idle between 3.5+ on the oil pressure meter. so when i first saw it idle lower than that, and stay that way, that was just weird to me.

and btw, my dad told me he actually serviced the car in 1998 for a new oil pump.......... so i can eliminate that problem.

LeMans71

Just to clarify the belt/chain question for you - all 944 engines have a toothed timing belt, which drives the single camshaft in the eight-valve engines (standard 944 like yours, and 944 Turbo aka 951). That same belt drives the exhaust cam in the 16-valve engines (944S and 944S2). Since the 16-valvers also have a separate intake cam which must also be driven, there is a chain between the exhaust and and intake cams. Consequences of failure of either are dire.

caseydt

Are there any more ideas on this? I have just purchased an 87 S and have the same issue, just worse. Mine has around 4 bar upon starting and while driving. Lowest it gets while the engine is cool is around 3. After around 10 minutes of highway driving the oil pressure will drop to 1 once the rpms drop. If the engine is kept at or above 2000rpms the oil pressure stays up. Oil level is correct and the weight is 10w-40. Should I try changing to 10w-50 as suggested earlier?

Thanks,
Casey

tdz

From the shop manual:

Oil pressure at 80C and 5000 rpm - approx. 4 bar

Your oil pressure of 2.5 bar at idle is okay if it goes to 4 bar at 5k with a warm engine.