pete944

What is the difference between the old & new style valves? I changed my oil cooler seals a month ago and I'm wondering which one I have. If someone can post pics that would help. I checked prices on the new style valve and was blown away. The thing is around $250!
While I was doing the oil cooler I also replaced the pressure sender. Since then the gauge shows 5 bar at startup and while driving but it only goes down to 4 bar at idle. Is that right? Before that it was 5 bar at startup, 3-4 when warmed up, and it bounced around at 1-2 at idle. Now it's rock solid at 4 bar and never goes below that (unless I shut off the car). Am I worrying about nothing?

Carl Nall

I pulled my old style OPRV yesterday. It consists of three pieces, plunger, spring and retainer. I understand the new stle is one a piece with o-ring seals. I cleaned and replaced the valve and my cold engine oil pressure is 5 bar and drops below 4 at idle when warmed up... usually 2-3 bar IIRC.

Could you have a bad sending unit?

pete944

The sending unit is brand new but I guess that doesn't mean it couldn't be bad. I think I still have the old style valve.
Does anyone have a pic of this gadget?

HY M8NC

<a href="http://www.pelicanparts.com/944/944_parts/944_83-85/pic2.jpg" target="_blank">Oil Cooler Diagram</a>

Updated oil pressure relief valve is part number "34" in this diagram. It is the one piece style, as opposed to the 3 piece (spring/piston/cap) of old.

I don't think it is the sender, when they go bad they peg at 5 bar and don't move.

One possibility is that you didn't get the oil cooler housing aligned right when you put it back on. There is an alignment tool that makes this easy. Some guys rely on the PRV to align everything-but that's dicey.

If you want to see which valve you have, remove the bolt on the outside of the housing. If it is a 1 piece, you will remove what's in the picture above, if it is the old style a spring and piston will fall out. My bet is that it is the old style, and the piston is hung up towards the closed position. If you can't get that piston to drop out-or use a magnet-you will need to remove the cooler. Good luck!

pete944

Thanks Ben. I do have the old style valve. I did use the alignment tool but it fit VERY tight and was a b!@#ch to get back out after tightening the housing bolts. Could it have been the wrong tool? The one I used was for an 85.5, are there different ones?
I'm not enjoying the thought of doing this again. <img border="0" title="" alt="[Frown]" src="frown.gif" />

pete944

bump-a-roo

M758

No there is only one tool for all cars, but the tool should not be tight. If it is the valve could bind. Anyway you will need to loosen and slowly tighten it until the cooler housing is tight and the tool is loose. It will take a slow process to get there.

Also remember that if you do update the Oil Pressure relief valve there is one set of o-rings for an "updated" car and a different set for a car that came with the new valve.

HY M8NC

I don't want to kick you in the nuts here...
There is only 1 alignment tool, but it should have dropped out fairly easily. When mine was acting up, we actually had to use a haller to get the old valve out, and then hone the bore. We were only cleaning out the gunk-not enlarging the housing. I'm sure you cleaned everything out before you put it all back together...but you may need to take it apart again.

I have been told that you can loosen the bolts on the oil cooler housing and rock it until you can get the PRV to move freely, although I've never done it. Seems you might jeapordize the seals.

I bought my used 1 piece valve from Parts Heaven (www.partsheaven.com), I paid $60 for the valve and put new o-rings on it. It was tested and guaranteed. No problems yet.

Perry 951

You cannot drop in the new relief valve in place of the old ones. The bushing it rides in is smaller on the older setup. Removing this bushing (even with motor out of the car) did not look like fun, and pressing it back is is probably about as difficult.

<img src="http://members.rennlist.com/perry951/images/motorbuild/Rebuild053sm.jpg" alt=" - " />

Pete, since yours seems to "stick" at 4 bar, I would assume the plunger is moving up enough to bypass some oil, but not all the way open to drop the pressure when above 3k. Probably mis-aligned as stated above.

M758

Perry,
That is why there are 3 styles
1) Old Spring
2) New valve
3) New Style valve for use in old cars

pete944

Ok, let me see if this will work.
I have the old valve and I'm not changing it. I ordered a new alignment tool today. They did show a different part # for the tool for the new style valve. When I did the oil cooler seals, the valve went in and out very smoothly. No problems there. The alignment tool would barely fit and once I got it in it took a good set of vice grips to work it back out. I wouldn't be suprised if the housing is off by a little bit. What is the problem if the valve fits nicely but the tool doesn't? I'm going to re-do the whole thing just to be sure but I need to know why the tool doesn't want to fit.`

Perry 951

I would not take it all back apart, just remove the valve assembly, loosen the housing, and use the procedure stated above, and below.

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">... you will need to loosen and slowly tighten it (housing) until the cooler housing is tight and the tool is loose. It will take a slow process to get there.</font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">

pete944

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Perry 951:
<strong>I would not take it all back apart, just remove the valve assembly, loosen the housing, and use the procedure stated above, and below.

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">... you will need to loosen and slowly tighten it (housing) until the cooler housing is tight and the tool is loose. It will take a slow process to get there.</font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica"></strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">The problem is the tool was never loose.

Perry 951

Even with the housing off? The tool only needs to fit in that brass bushing, and if it is too tight there, that is not good. Either you have the wrong tool, or a mugged up bushing....

pete944

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Perry 951:
<strong>Even with the housing off? The tool only needs to fit in that brass bushing, and if it is too tight there, that is not good. Either you have the wrong tool, or a mugged up bushing....</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Yep. Wouldn't fit with the housing off. Thats why I think the tool was wrong. I don't know how the bushing could be messed up. The valve moves freely and the oil pressure was ok before the cooler seal job. Nothing went in there except the tool.