jtessaro

The other morning I started my 944, which I had just had a bunch of problems with (explanation to follow), warmed up the car until the temp gauge was indicating the car was warm (about 5 minutes) and due to my previous problems with the car slowly revved it to about 3000rpm, to see if it would run. The car suddenly started blowing white smoke like you would not believe and apparently blew all of its oil on the ground. The oil pressure gauge had been reading high but I didn't think anything of it because of the cold weather. Here is the experience I have had with the car so far:

I just bought a 1987 944 with 53k miles on it, there is paperwork showing that the transmission, timing belt, and water pump have all been replaced within 5k miles.
2 days and 140 miles after I bought the car the oil light came on and the pressure gauge was pegged high I stopped driving and noticed a ton of oil in the coolant and from what I could tell there was no water in the oil. I ASSUMED it was a blown head gasket but it turned out to be a cracked oil cooler. Needless to say that was an expensive fix, I drove the car home from the mechanic without any problems.
The next morning the car started fine but I pulled out of my driveway accelerated and shifted into 2nd gear and the car died, figuring I just stalled the car I started it and tried again--same thing. I messed with it some and found that the car would stall every time I hit about 2800rpm. I decided the problem was fuel related and deduced that since the car had been sitting for about 6 months with a half empty tank, condensation had built up and the lines were now frozen. I added some dry gas, pulled the car into my garage to defrost and 8 hours later was able to run it and eventually baby it above the 2800rpm mark and get it running.
I ran the car to work and back the next morning, and besides having to baby and warm up the car when I started it to come home there were no problems.
And this brings me to the oil problem I just explained.

Now I took a look under the car to see if there was anything obvious and could not find any problems except for a strangely misplaced oil filter gasket. I filled the car with oil (5.5quarts) and ran it for about 20 seconds trying to find the leak but found nothing. I called a mechanic and he said that sometimes on the 944s the oil pressure relief valves will get worn and stick causing high oil pressure and blowing the gasket around the oil filter.

Now I'm wondering if his diagnosis sounds right and if there is anything else that could be causing my problems. After hearing the mechanics diagnosis it sounds plausible because the oil pressure gauge has been high since I bought the car.

If the problem is the Relief valve is there anything I can do to fix/clean the valve other than replacing it? the part costs like $350 but is thankfully rather easy to get to.

Any help would be greatly appriciated, I can answer any questions and provide more information if you respond here or email me at jtessaro@connecttime.net.

thanks,

Josh

KuHL 951

Since the oil cooler housing was recently replaced it's very possible that the OPRV was not aligned correctly using the correct tool. This will cause the OPRV to bind and can malfunction. Check to make sure the o-ring on the end of your OPRV is still intact, it might have rolled off and is plugging a passageway. Usually low oil pressure is more common. Don't shell out for a new one until you see the one in there now. In all honesty there is little to go wrong mechanically on the one piece OPRV except the inner and outer o-ring or misalignment of the housing.

jtessaro

Thanks for the input, I have not yet had time to actually remove the OPRV and take a look at it but I think I will get to it tonight and will take a look at the O-rings.

jtessaro

What tool is needed to correctly align the OPRV during install? and how do you tell whether it is aligned or not? is that done simply by checking the O-rings?

KuHL 951

The correct tool for the 87+ is:

OPRV Alignment Tool

Many people including myself have used the 1-piece OPRV as the guide and gotten by. It's when the cooler housing is installed with nothing in the OPRV bore that things ca go south. You will not be able to see the inner o-ring when you pull the OPRV, just the lower one. It should look like the lower one in the photo.

IGROWL

Steve,

What is the difference between the two items in the picture above? I am having the same issue and was told by my mechanic to buy another OPRV. I just ordered from another Rennlister last night.

jtessaro

Ok you pretty much answered my next question which was going to be what you were speaking of when you mentioned alignment. So my next and hopefully last question is as follows:

I talked to the mechanic who did the oil cooler and he said I have the original OPRV which is the two piece valve, he also mentioned that he just left the inner piece in the block so no alignment tool was necessary. Frankly I question his knowledge as none of the responses I have received have mentioned anything about the 2 piece valve and part of a procedure I found online to replace the oil cooler states that all '87 engines were made with one piece valves. https://rennlist.com/techarticles/heatexchanger.htm

Now would having the 2 piece valve make any difference alignment wise and if it is not aligned that means I have to remove the oil cooler and housing correct?

VaSteve

It's possible with the 2 piece (really 3....plunger, spring, cap) OPRV to leave the plunger in place and line up the housing off the lip of the plunger. I did it and mine wasn't building pressure, so I pulled it all apart and checked it with the tool. I had a piece of crud in there keeping it from seating. I had no problem getting the tool into place, but I was lucky. It's a tough spot to get something aligned. It's a hell job with the engine in. The very existence of a tool, probably indicates that it should be used.

Unless it got bent or otherwise f*ed up, I don't see why you'd need to replace it.

jtessaro

thanks for all your input... in both my threads. I'm taking it apart in about 20 minutes

KuHL 951

I don't know what to say other than you have an 87 engine correct? Here's my take on what is wrong and there are two possibilities here:

1. You have a older 3-piece OPRV (see pic) made for 83 to 86 block only and your mechanic is only counting two of the parts or doesn't understand the 944 engine. Let's hope not because a 3-piece will not work in the 87+ block and never will;

2. You have the correct 1-piece OPRV and the lower end has fully separated from the cap end and the inner o-ring is lodged somewhere you don't want it to be. This too is really bad as you need to fish out the missing parts still in the opening.

You need to find out exactly what style OPRV is actually in there.

For Sands944 look at the placement of the o-rings and depth of opening at the tip. The upper OPRV is a 1-piece to replace the 3-piece style and only works up to 86. The diameter of the early OPRV is smaller as the block has a sleeve and the later blocks dont.

3-piece and 1-piece early conversion OPRV

jtessaro

I took the plunger and spring off and as mentioned earlier in this thread the O-ring from the tip of the plunger is blown and I can see a little bit of it past the end of the plunger. Now I messed with the plunger a bit and it is pretty stuck and assuming the cooler housing IS aligned with the OPRV bore does anyone have any suggestions as to how to remove the plunger?

I honestly don't know if the plunger was cause or effect, did misalignment stick the plunger cause the O-ring to blow or did the fact that the O-ring blew stick the plunger?

And as a response to the type of OPRV all I know is that the cap that I took off looks very similar to the one on the one piece pictured above both in shape and alloy type, and from what I can see the inner part as well is a similar color to what I have in my engine. I wonder if the mechanic didn't break it thinking it was a 3 piece valve...

jtessaro

I went ahead and took some pictures of both the pieces I pulled out and what is stuck inside still. (All I had was my camera and Paint so I apologize for the size of the photos.)

KuHL 951

Wow that is scary. The good news is you have the correct 1-piece. OPRV in there. The bad news is that it has separated completely and is the first one i have seen or heard of doing that while in the block. That can only happen with brute force and a misaligned housing. You would know what i'm talking about if you have ever tried to get to the inner o-ring with OPRV clamped in a vise. I hate to say that you might have to completely remove, or at the least, loosen the oil cooler housing to free up the lower end of the OPRV. I think your mechanic owes you an explanation and should repair it at his expense.

jtessaro

yeah thanks for your help, I have a feeling the mechanic is going to deny responsibility... this really sucks

jtessaro

Can it be reassembled with new seals? it sounds kinda like you have done it before, or do I need a new one?