In previous thread I was having a problem with my 85.5 944 having no oil pressure reading on startup. I went outside to start the car again to see if the guage was right and started the car cold just now and it had no pressure (lifters were tapping) for a short while and then it came right up to 5 bar andthe engine smoothed out.

So what could this be? I just did all the belts and seals including the cooler. It has been fine all week but this problem started today.

I made sure that the P/S pully sat properly around the crank snout when I put it back together. Maybe I missed something.


When I did the cooler (3 pc OPRV) I used the piston from the OPRV on the end of a dowel to check for binding. The guy at Zims claimed that the tool was not nessicary for the 3 piece valve.

I have done timing belt jobs on my own and customers 944's &928's past with no problems.

But this is the first time I have done the cooler seals. Could the valve be sticking? Or possibly the pump not engaging?

I need some help on this one as I dont know whether to look at the crank or the OPRV first.

 

Did you do anything to the crank pulley bolt during your belt work? I had very similar symptoms as you. I was never able to get the old 3-piece OPRV on my 86 to work right after, cleaning it, polishing the piston, etc. I ended up putting in the 1-piece conversion OPRV for the <86. I thought the old 3-piece units were the ones very suseptible to misalignment and needed the tool. The later 1-piece OPRV I thought can be used as a guide for aligning the case. Anyway my 1-piece conversion solved by problem of slow build or no pressure at start-up after I blasted some crud out of the bottom of the housing. See if you can borrow a conversion 1-piece OPRV from someone to try it out just to eliminate that as the problem. Hope you solve it.

 

Did you take your valve out to do the seals and then the problem started? Or did it just happen. I was noticing that the car did take a bit longer to build pressure that normal upon startup.

Yes, I had the crank pullies off when I did the belt job. I changed all the belts, water pump every seal on the front of the engine, including the crank seal, and I had the oil cooler off and changed those seals.

I am going to go out to the garage tonight and reinstall the flywheel lock and check the crank pully alignment and retorque it to 150ftlbs. If that doesent fix it then I guess I can assume it is the OPRV.

Any other thoughts???

 

I never removed the housing, my problems just started out of nowhere and got progressively worse over time. Did you pull the oil pump and have to reseal at all? Sometimes the match up with the mating surfaces can have a slight step in it that requires a bit more of the anerobic sealant to bridge. I doubt if that's the problem but a bad seal will keep the pump from priming right. I would still suspect the OPRV. Here's what mine would do:
1. Oil pressure was always very high( 5 bar at cruise and cold idle; 3.5 to 4 at hot idle) I even posted a question here about it;
2. It started not building pressure at start-up after sitting a week or so (non daily driver);
3. Finally it wouldn't build any pressure for 30 seconds so I started on the troubleshooting. My old 3-piece had minor scuffing and the tube insert showed the same thing.
4. Installed a used 1-piece conversion with new o-rings and the car has been fine since.

I think when I switched to Mobil 1 from dino that it washed some crud off the walls and started the OPRV to bind when cold. I can't say this will work for you but it sounds similar to your problems.

 

Kuhl, my oil pressure was high like yours. Checked the oprv, no problems, a slight amount of mixing. I pulled the cooler housing, and the cooler. Full of jelly. The seals on the cooler were bad. After sitting, the coolant would seep into the oil cooler. I re-aligned the cooler housing with the one piece oprv, no problems as of yet. The car runs JUST under 5 bar at cold idle, and rpm's over 2500. After the car has run for 15 20 min, the idle oil pressure drops down to 3.8 4 bar. This is in line with pre-mixing oil pressures. I do run 20w50.

 

Luckily I've never had the mixing. ClassJ did replace his housing seals so alignment might be the issue. I agree, I always thought the alignment issues were more critical and were geared towards the old 3 piece units and not the later design which can be used as a guide. My OP is great now and very predictable. I feel anytime a problem with OP starts suddenly out of nowhere it's either the OPRV or a cracked pick-up tube from bad motor mounts. The rest of the lube components are not prone to sudden failure. Now if I can just get my fuel cutout issues resolved I'll be a happy camper..

 

Have you checked your DME engine temp sender?

 

Funny you should ask, that's one of the things I'm looking at this weekend. My impression is that a bad DME temp sensor will do weird things until the engine warms up and then will run fairly normal...but from what I've read it will screw up all kinds of things through the whole power band. Believe it or not my TPS was completely toasted, probably has been for awhile, and the car ran fine..I checked it for the first time and had no click at all and replaced it with a spare I had. The car was smoother when backing off the throttle and less blub blub in the exhaust but the cut-out was still there under load right before boost onset. Kevin, can I PM you and discuss this futher? I don't want to hijack this thread with my own issues. A fuel filter replacement is going in tomorrow as normal maintenance.

Steve

 

I had no mixing problems but I replaced all the cooler seals as a matter of preventitive maintinence. Even thought the car has only 30K miles on it, age is more relevent to seals usually.

I am pretty sure it is the oprv. I was carefull when I installed the pullys up front to make sure that the ballance pully and the P/S pully were seated properly. I torqued the bolt to 150 with locktite. I dont see how it could have loosened but I am going to check it.

I pulled out the oprv, there was slight scuffing on it and a couple bits of hard gasket matirial clinging to it. I am going to get the tool and line the thing up and go from there. Maybe I didnt get it right using the piston as a makeshift tool?

I know that there are two tools, is the early tool correct for the early housing regardless of which valve you use? Or do you need the new tool for the new valve.

thanks for the help

 

Clark's Garage says it helps to manually turn the crankshaft counterclockwise a full turn to prime the oil sump and galleys, before starting the car. I also pour some new oil into the small hole above the oil filter boss, prior to installing the filter. Also, be sure the oil filter is OEM Mahle, Porsche, or Mann with the internal pressure relief spring and sub-canister too. It really make a difference

Zach