how to proceed on old oil cooler and oprv

Naturally aspirated tech and talk
Post Reply
Carlier944
Posts: 7
Joined: Thu Feb 20, 2025 10:56 pm
Has thanked: 7 times
Been thanked: 4 times
Hi guys,

Always loved the 944 and proud owner since a few months. I bought an 944 na from 82, so probably it's one of the first ones that left the factory. It was imported to the Netherlands (where I live) from Germany in 1991.

It's leaking oil at all the usual spots so I'm now gradually going through those. I've just removed the oil cooler. Unfortunately it's an 5r, so it was never updated. That was confirmed when I removed the OPRV, which is the old school original one. When I removed that the top part didn't want to come out, so it's still inside the metal sleeve that's sticking out of the block (see attached pictures).
sleeve.jpg
sleeve.jpg (1.49 MiB) Viewed 1230 times
OPRV.jpg
OPRV.jpg (1.02 MiB) Viewed 1230 times
My questions now are:

1: should I upgrade to the retrofit OPRV valve (944 107 035 11)? I see them on Ebay for around 200 dollar. Shocked by how much they cost new. So cost is an issue here.
2: should I upgrade to the 6r housing?

What are the things to take into consideration here? Is this setup fine or does it justify the costs to replace them?

also question 3: how to remove the top part of the old OPRV from the sleeve? Any tricks here are greatly appreciated.

Thanks for reading and all info on this is welcome.

cheers,

Eelco

#1

Top
gb951
Posts: 80
Joined: Mon Apr 03, 2023 10:09 am
Has thanked: 23 times
Been thanked: 36 times
1) The plunger in your picture is stuck. If you can remove it without doing any damage (use a pliers with copper jaws) you may be able to reuse it. Only after you have it out of the engine will you be able to tell. I have the original 3 piece OPRV in my 84 944 and it works just fine. No need to spend the money on a 1 piece OPRV if you do not need to.

2) No need to upgrade to the 6r housing. You will need to use the alignment tool to properly locate the housing.
There is a Tech Service Bulletin for the oil cooler housings. If you cannot locate it, I can provide it.

3) Heat and soft jaw pliers might do the trick, You won't know until you try it.

#2

Top
Carlier944
Posts: 7
Joined: Thu Feb 20, 2025 10:56 pm
Has thanked: 7 times
Been thanked: 4 times
Thanks! Will start to try removing it first. Then make plans accordingly :)

The vibe I got online was that it's usually better to switch to 6r and go retrofit on the OPRV. Good to read that this setup works fine as well.

#3

Top
User avatar
Tom
Site Admin
Posts: 8933
Joined: Fri Jun 25, 2021 2:04 pm
Location: Silicon Valley, CA
Has thanked: 932 times
Been thanked: 3994 times
Contact:
Contact Tom
Carlier944 wrote: Tue Apr 01, 2025 9:13 am Thanks! Will start to try removing it first. Then make plans accordingly :)

The vibe I got online was that it's usually better to switch to 6r and go retrofit on the OPRV. Good to read that this setup works fine as well.
gb951 is the long-time 944 Technical Expert for the Porsche Club of America, so his advice is about as good as it gets. :)

If you clean all the oil and grease off the stuck plunger, you might try a rubber strap wrench on it to free it up before trying pliers, especially (!) if you don't have any soft-metal pliers of the type gb suggests. You might try to soak some solvent in there overnight too.





Home made hack version might work too...

#4

Top
barnwerks
Posts: 92
Joined: Sun Mar 10, 2024 7:21 am
Has thanked: 1 time
Been thanked: 36 times
With the "plunger" stuck, you will need an inside grab, not outside.
A tapered thread such as a pipe thread or lag screw thread may engage the ID and give enough purchase for removal. Regarding the upgraded valve, the original design works well but must be accurately aligned with the housing.

#5

Top
Carlier944
Posts: 7
Joined: Thu Feb 20, 2025 10:56 pm
Has thanked: 7 times
Been thanked: 4 times
thanks for all your replies. I won't have a lot of time this week so probably I'll continue in the weekend. I'll might need to resort to that fancy improvised tool as well :)

groet,

Eelco

#6

Top
gb951
Posts: 80
Joined: Mon Apr 03, 2023 10:09 am
Has thanked: 23 times
Been thanked: 36 times
This tool may be useful for extracting that plunger..

https://www.amazon.com/8MILELAKE-Bearin ... B07JVJ6GWL
pilot bearing puller.jpg
pilot bearing puller.jpg (43.59 KiB) Viewed 1157 times

#7

Top
User avatar
gruhsy
Posts: 517
Joined: Mon Jul 05, 2021 10:02 am
Has thanked: 48 times
Been thanked: 81 times
A slide hammer will work with this.

Make an attachment with the same threads as the pressure relief valve and a female end that threads onto a slide hammer.

Since you are in the Netherlands reach out to DRS development and have them make you one.

It would probably be useful to them as a Porsche shop.

https://www.drsdevelopment.eu/contact/

https://www.drsdevelopment.eu/

#8

Top
Carlier944
Posts: 7
Joined: Thu Feb 20, 2025 10:56 pm
Has thanked: 7 times
Been thanked: 4 times
Short update; turns out you can just remove the plunger with by sticking your little finger in and pulling it out, so no tools were needed to extract it.

I will keep the old 5R housing and old OPRV. Figured: if it worked for 43 years, it probably has proven that there is no real issue with it under normal driving conditions.

Thanks for all the help though, I'm sure I'll run into other issues and now I know there is a great community to turn to.

#9

Top
Post Reply