merchauser

Reinstalled water bridge and added the paper gaskets to the O rings as recommended in a Porsche bulletin.
No leaks before, but now I have a seeping (minor leak) at the center O ring. It seems that the thick paper gaskets
have added some height to the water bridge and the center O ring is not seating all the way down. with WB installed,
I can see a very fine line of the black center O ring; don't think that was visible before.

anyone else had this issue after adding the thick paper gaskets???

jtrygstad

I had the same problem when I added the paper gaskets per the Porsche bulletin. Got rid of the paper gaskets and lubed up the o-rings with Dow Corning silicone grease. No leaks.

GregBBRD

The surface where the big O-ring sits has to have been "eaten" up with corrosion....probably on both sides of the original O-ring (like 90% of the ones I see), if you cleaned this surface. If you didn't clean this surface very well, there will be raised corrosion "patches". Raising the assembly puts the new big O-ring right into the pitted aluminum surface or on the raised corrosion patches.

Leave out the paper gaskets and apply a very thin layer of Drei Bond to the two aluminum mating surfaces. Use something very slippery on the big O-ring (I use HSS.)

merchauser

happy to report there was less than 90' worth of very minor surface roughness where the O ring would sit in the block; great shape.

only use the drei bond? leave out the thin O rings?? can I dress the large O ring with Vaseline?

GregBBRD

I really have no idea. I find something that works every time and use that method forever.

I leave the red O-rings in place.

NoVector

It's been about 2 months since I installed mine and so far, so good. I used the paper gaskets and the red silicon O-rings AND I followed Stan's advice and used Permatex Ultra Blue RTV. I used drei-bond 3 years ago on that area when I did the intake refresh - it apparently didn't work so well for me. It looked like one of the paper gaskets split so maybe I did something wrong when I installed it. Although I'm pretty religious about following torque values.

The red O-rings seemed thicker this time. When I put them in 3 years ago I remember thinking "no wonder they want us to use the paper gaskets, the O-rings are flush with the grooves in the bridge." This time they seemed to be thicker and extend above the recessed grooves (as one would think they should.)

So on 27 July 2018, my vote is use the paper gaskets and red O-rings and Permatex Ultra Blue RTV. However, if I pop another leak tomorrow, I take back everything I said. Or said another way, I don't have enough miles or heat cycles to say definitively it's a winning combination.

Fogey1

Do you mean Wurth HHS?

SwayBar

I've used the blue Hylomar(?) many times without any leaks.

GregBBRD

Yes. We use it on every O-ring to allow them to slip into position without cutting or binding. Engines, transmissions, everywhere.

There's only a few paper based gaskets that we use sealant on...and never a silicone based sealant. The "thicker" German gaskets that have distinctly different color/texture on each side, actually have a "built in" sealant in them, to keep them from slipping or splitting. Putting a silicone based sealant on these gaskets is probably the worst thing to do....they split and leak virtually everytime.

I have no experience with many other types of sealant...they just are not even in my arsenal of things to use. I've got Drei-Bond, HSS (not a sealant) and Curil K2 (and I only use that in a couple of places)....that's actually about it.

Again, once I figure out what works everytime, I don't experiment with other stuff...there's no need.