The Complete Engine Sealant Thread...

[Tippy]

Originally Posted by John McM

I have a leak at the Intermediate Shaft cover on my 964. I checked the engine building DVD and saw they fitted the o ring and cover with no sealant. However this thread talks about Threebond 1211. I want to use that. Where do I apply the sealant? Just around the exterior cover?

Looking at this again, it appears your right case is proud vs left side.

If so, it'll be really hard to seal that.

[DRACO A5OG]

Glad I am seeing this.

Almost ready to assemble the engine, I did notice there is allot of movement to place the case together, I know #8 will help align it but the for and aft can also be an issue of the two mating surfaces.

[John McM]

I put the jack under the engine right next to the drain plug so I had to take the cover off and let the oil drain from there. More than 4 litres of oil came out. That's a lesson for next time if there is one!

The cover, o ring and case bore had traces of some type of sealant. I used a plastic trim spatula and finger nails to remove it all. I was careful not to drop any in the opening at the base of the bore.

The case halves are not perfectly level at the case join but not that bad. Equally the cover appears straight.

[John McM]

I then put a smear of oil on the o ring, the cover channel and slipped the cover back in place. It went very smoothly. I torqued the bolts to 10 Nm (less than I think the previous installer used), degreased the area and put 1.5 litres of oil in. Now I'm watching for any leaks before I go any further.

[nickd]

John, I notice some extra info on here from the rennlist thread. The hammer marks on the cover would worry me. I would hope that a new cap from Porsche wouldn't be too expensive. Though maybe the incorrect use of a sealant on the o-ring is the real problem.

I don't remember anymore from when I replaced this o-ring, and I wasn't sure from the descriptions above- can you feel any kind of lip inside the o-ring bore where the case halves meet?

For another data point on sealants, I followed Henry's recommendations on my 964 rebuild and it's 100% leak free (except the nose bearing/ims area) after a few years, around 10k miles, and hundreds of autocross runs. I didn't split the case but I did replace the through bolt o-rings one at a time. Many of them came out mangled. The motor had about 70k miles and had never been opened before, so the factory must have destroyed a few o-rings during the original assembly. It had a number of leaks from the through bolts. I would put dc55 on my pancakes if I could. Love that stuff. Good luck John.

[John McM]

Yesterday, I put everything back together, ran the car for 5 km and it still leaks

Tonight I pulled it all apart and while oil is notorious for spreading to obscure its source there appears to be an obvious gap in the RTV on the top side of the Intermediate shaft cover. I've cleaned the area up and will check in the morning. Then I will put the engine back on the mounts and run it. Would taking out the DME and turning it over with the starter motor generate enough oil pressure to test this? I really would prefer not to start the motor.

[Tippy]

Well, if your cases aren't flush as they appeared in the photo above, here will be my ghetto fix.

RTV is a huge no-no on aluminum, but I think you're forced to use it in this case. All the non-hardening sealants are just too weak IMO.

So, with that said, I'd remove the cover, clean up everything again with brake cleaner, and try a light amount of RTV.

In the US, we have Permatex Ultra Grey. Not sure what's in NZ?

The key is to apply it and carefully put the cover back on ensuring the RTV doesn't get mashed unevenly.

Torque the bolts to 50-75% of final torque.

Let it sit 2 hours.

This allows a "gasket" with high durometer to be formed.

Then torque to final.

Some will balk at this, but I have lots of experience fixing leaking old Chevy V8's!

[Ed_914]

Don't know if it is a good idea but i would oil stone the 2 halves and create a flat surface

[KTL]

The intermediate shaft cover for the 964 3.6 is the same as the 993 3.6 and also the same as the Carrera 3.2 from '84 to '89. Part number 930.105.165.00 So the search for a good used one could come up pretty easily.

Henry's offer of the good used one for the cost of shipping is probably the best deal you're going to find. Put a new o-ring on it with silicone grease and you should be all set.

[John McM]

Thanks all for the comments, all of which have good thoughts.

The new cover is $28 from Pelican and I have a big order in anyway so will add to that. Thanks for the offer Henry in any case.

I will have a very close look at the mating surfaces. I like the oil stone idea to ensure a completely flat surface. I will use a new cover, o ring and silicon. Is threebond 1211 ok for the RTV idea? Right now all of the red RTV is external. I gather I'm working on sealing full oil pressure here.

[Henry Schmidt]

Originally Posted by John McM

Thanks all for the comments, all of which have good thoughts.

The new cover is $28 from Pelican and I have a big order in anyway so will add to that. Thanks for the offer Henry in any case.

I will have a very close look at the mating surfaces. I like the oil stone idea to ensure a completely flat surface. I will use a new cover, o ring and silicon. Is threebond 1211 ok for the RTV idea? Right now all of the red RTV is external. I gather I'm working on sealing full oil pressure here.

No worries, we have a huge inventory on these kinds of ancillary parts.

If the cover really require a sealant I would use Dow 55 and LocTite 574 on the perimeter making certain not the get it on the o-ring. In the alternative, 1211 can be used to seal the o-ring.
In this application it's important not to use a lubricant that will cause wicking.

[John McM]

Just ordered the Dow 55, more O-rings and a cover. I have 574 but don't like the chances of keeping it off the o ring. I used Wurth's orange flange sealant on the valve covers, but decided not to try it on the oil pressure sender due to the risk of getting it in the oil. Is 1211 a safer alternative?

As soon as I can get this engine (relatively) leak free I'll pull the engine out my other 964 and prepare for a Southern Hemisphere Winter of rebuilding that. It's great to know there's a group of people out there so willing to share.

[John McM]

Plans have changed. A closer look indicates that the JB weld has seperated from the case and the area is leaking. Unfortunately, the collar has to come off but the JB weld is holding strong on the bond to the other parts of the bearing area. I don't want to use heat near the bearing and use of tools without marking the case are problematic. That combined with a call to the OPC where it's clear I won't be getting a pickup and redelivered engine has me starting the reseal process myself.

Thanks for all your help here. I will be back with reseal questions. Luckily I have two cars.

[John McM]

Gratuitous pic of cars. The White car on the lift is the one prepped for surgery

[racing97]

You must be in Austraila

[Trackrash]

Originally Posted by racing97

You must be in Austraila

LOL, Actually New Zealand. Still its down under...

[Alan L]

Originally Posted by Trackrash

LOL, Actually New Zealand. Still its down under...

JAFFA land I'm guessing?
Alan

[John McM]

Originally Posted by Alan L

JAFFA land I'm guessing?
Alan

Yes, Auckland aka Just Another F.....g Aucklander land to those not in Auckland

[John McM]

Originally Posted by Trackrash

LOL, Actually New Zealand. Still its down under...

Way down under, a fact we are reminded of each time we see the shipping cost. Despite that, the final costs shopping at Pelican and others overseas are far less than local ones, if we could find the items.

[Alan L]

Originally Posted by John McM

Yes, Auckland aka Just Another F.....g Aucklander land to those not in Auckland

Have you tried discussing the fix with Steve Rassmo - he is usually quite helpful and knowledgeable.
Yes, the shipping costs ex US often double the price of the item, but the supply of bits is unbeateable.
Alan