944ZEN

My engine was "bleeding" oil so monday/Tuesday i changes the seals in front off engine (bal. shaft and crank), and changed the belt's when already in there. (My first engine job on a 944)
When the engine is really cold, the oil pressure stays on '0' Zero for 15-20 sec, then goes to the normal 5. The oil warning light is also on for the 15-20 sec, and i think i can hear that the oil pressure is not up, since the engine sound changes after the light goes out an the gauge reads 5. (less knocking).
I checked the oil level, and have not changed the or filter.

What IS WRONG ? ?

? ? Is it the oil pressure relief valve that stays open for some seconds, or ? ? ? as i read in the archive it could maybe be the torque on the crank bolt (used a torque wrench set to 210 Nm).

I must say that at first i assembled the gears on the oil pump wrong <img border="0" alt="[ouch]" title="" src="graemlins/c.gif" /> , forgetting to put in the washer that goes directly on the oil pump. So i had to come to the garage yesterday and pull the belts and gear's to put in the washer, and the problem started.
Experience wanted

Luis de Prat

A fellow in the E-Mail lists had a similar problem after an engine rebuild. His oil pressure indicator kept lighting up, although the car seemed to run OK.

I'm not sure if this would apply to your situation since you don't appear to have taken the oil pump apart, but in this fellow's case he needed to "prime" the oil pump, that is, fill it with oil, in order to keep the oil pressure up. He did this and his oil pressure problems were solved.

Bri Bro

Look at this link
<a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic;f=15;t=020757" target="_blank">http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic;f=15;t=020757</a>

944ZEN

Thank for the answers/link, i will try tighten the cranck bolt some more and see.

ahofam123

Wouldn't a loose crank bolt never register an oil pressure. I am having the same problem where it registers after 15 seconds. I cleaned the OPRV and it looked good but I'm still having the problem.

944ZEN

I tried to tighten the cranck bolt on the street, but i was as tight as i could get it.

Even worse, friday morning the engine failed to get oil pressure at al, even after 50-60 second's idle running. I decided to shut the engine, and got the car towed to my frinds garage (20 mile trip).

I removed the belts and gears, and replaced the rubber o-ring that sits beween the trust washer and oil pump drive. I assembled the whole thing again, engine runs fine but stil no óil pressure.

The motor guru in the garage suspected the Oil pressure Relief Valve, and we pulled the spring, but was unable to pull the piston, but by inserting a finger we were able to move the piston.
I sprayed some anti sieze spray (Mo2So-oil i think) into the relief valve opening, and we blew it clean by compressed air.

Stil no Oil preassure

The "motor guru" suspected air in the oil system, and wanted to prime with oil.
We removed the oil pressure sender unit, and primed by injecting some clean engine oil. And the "Motor guru" put on his thumb to feel if any preassure was in there. NOPE <img border="0" alt="[crying]" title="" src="graemlins/crying.gif" /> Still no pressure.

Then the "guru" suggested priming at the oil filter console. So off with the filter, and i squirted some clean oil into the opening, and refitted the filter.

VOILA! After 15 sec. idling the pressure vent to 5 on the scale, as normal.

And then it was time for a <img border="0" alt="[cherrsagai]" title="" src="graemlins/drink.gif" /> after the 4 hour's work.

So actually we did'nt find the actually cause for the oil pressure loss, but we curred the problm for now.

I'm still quite worried though, since the engine was run for like 120+ second with no oil, and that we did'nt find the actually problem.
Everytime i fire up the engine, i look like a idiot <img border="0" alt="[oops]" title="" src="graemlins/oops.gif" /> at the meter, and i thin i see the pressure takes time to build up, like 1-2 sec. before reaching 5 on a cold engine, but i don't know if this is normal.

I want to run a oil-cleaning agent one off these days, and replace oil, and filter. Hopefully this will cure my worries.

So i can <img border="0" alt="[burnout]" title="" src="graemlins/burnout.gif" /> again.

Eric

ZEN,

This may alleviate some of your concerns, but when starting my car cold, the pressure guage routinely takes 10-15 seconds to "build". I recall this being the case for the past three years with no major problems.

ahofam123

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Eric:
<strong>ZEN,

This may alleviate some of your concerns, but when starting my car cold, the pressure guage routinely takes 10-15 seconds to "build". I recall this being the case for the past three years with no major problems.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">How long does it take for everyone else's oil pressure to build up? Its odd because mine takes about 15 sec. on a cold engine, but then when I start it on a warm engine, the pressure registers after only 1 sec. Can the OPRV visually look good but indeed be bad? Can a brand new oil filter have an anti-drain valve fail straight from the box?

Manning

Mine starts to register pressure as soon as I start cranking the car over and it builds very quickly as the car runs for a few seconds.

When I had that stupid piece of crap C&M cartridge style oil filter on my car the anti-drainback valve (basically a rubber flapper) would wear out after about 300-400 miles and I would have dry start problems like you describe. And yes a new oil filter right off the shelf can have this problem. I think it is Fram filters that are notorious for this.

By the way, at the request of Luis I contacted Canton Mecca (C&M) about the trouble I was having with their filter and have yet to hear back from them about it. This on top of their original attempt to dismiss it even happens.

adrial

I get instant oil pressure...anybody that doesn't...you better make sure you're using an oil filter with the correct anti-drain back valve! Mahle and Purolator have worked great in my experience. I use Mahle 99% of the time. I used Purolator once when I was out of filters, but needed to do the change...so I bought one locally.

944ZEN

Now i have had a couple of cold start, and the pressure build-up seems to take 2-3 sec. on cold engine and almost instantly on hot engine, and it's the same every time. Still same filter and oil.

B.T.W. The filter i use is the German MANN W719/22, and the oil is Duckhams semi-synthetic. W10-40. I will go full synthetic. for next change, since all seal but back crank is now changed, and no oil is dripping.

Maybe all you who have 15 sec. build-up time is about to have a sticking OPRV, maybe time to run a oil cleaning agent at next oil change.

I'm getting more happy every time i fire up the engine. It also seems like it have gained more bottom end torque, and mid band HP, so that belt change was OK.

Actually the Porsche shop that did the last belt change, set one off the balance shaft one teth off. So no i got an even smoother running engine Yeah...

I'm getting more and more happy about this car <img border="0" alt="[jumper]" title="" src="graemlins/jumper.gif" /> I'v just ordered a new cooler and a clutch kit, then it will be in real good running condition.

ahofam123

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by adrial:
<strong>I get instant oil pressure...anybody that doesn't...you better make sure you're using an oil filter with the correct anti-drain back valve! Mahle and Purolator have worked great in my experience. I use Mahle 99% of the time. I used Purolator once when I was out of filters, but needed to do the change...so I bought one locally.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">I bought a Purolator filter for this oil change just because I didn't have a Mahle handy. I can see the anti-drain valve in it but it still cold starts. What are the signs of a bad OPRV? I guess I'll remove it and clean/lubricate it again to see if it makes a difference.

billybones

Maybe the pressure sending unit itself is gunked up? and takes time to react.

Manning

Yeah, that's a good point. If you are dry starting you can definitely hear it, especially if it is taking 15 seconds to build pressure.

ahofam123

Thanks, from the cabin I notice no difference between the startups. I'll listen near the engine bay and look into the sending unit.