Five-8

Hi All

Here is a pic of the replacement waterbridge i am going to install.There clearly was some kind of rubber type sealing ring- not much left of it now AND in my original waterbridge there was no remaining evidence of one, so i am guessing it completely perished.
This part does not show in PET, and the car seemed to be running fine without one...so my question is of course do i need it and can i still get it if necessary?

Thanks!

Five-8

Ok so i have looked a little closer...the two waterbridges are different.Here is the pic of my old one.
Upon looking a little closer...it appears that the replacement requires a sealing ring( i can now see the recess and the metal ring.My original does not have the recess.
I assume once i get the sealing ring all will work fine?

Bilal928S4

Yes. On later cars you need the sealing ring (my experience on S4's only).
It is 928 106 163 00

Five-8

Appreciate the help...thanks!

Cheers,

davek9

Also on S3's, so maybe all 32v car's

Mrmerlin

IIRC the rear sealing ring was started in mid 1984

Five-8

Woulda been nice if they changed the part # ,even if only slightly to distinguish the very minor change.(Stamped part # are identical on the 2 units)

As far as i can tell there are no other differences between the 2 units...but stay tuned..havent installed it yet.

BTW..is this part# thing consistent with other parts? What i mean is, change/upgrade the part but leave the part# the same?...seems somewhat un-German--like behaviour to me.

Cheers,

Mrmerlin

its also possible someone installed the seal into a parts that didnt require it.

NOTE I would need both old and new WBs to verify this to see if there is any difference

Five-8

Stan..they are clearly different.I know it doesn't show well in my pics, but my original, has no tooling to accept a seal...whereas the replacement(newer?) does.

Without seeing a fresh seal in situ it is hard to tell, but methinks it will have the same dimensions as the original(sans seal)

Cheers,

littleball_s4

The seal is like a hat without the top, so it fits in a plain hole, no need for machining. Diameter is important, of course.

That seal seem important. I replaced it today (along with tstat and oring). Tstat checked ok, old o-ring was different, square section, but looked ok. Only thing clearly shot was the seal, and it my car overheat at idle and low rpm. Not anymore.

Anyway, I don't understand much about cooling. I've seen Tstat open and I don't understand how this opening is enough for the big *** pipe that attach to it. Someday someone should enlighten the matter.

WallyP

In some cases, the number on a metal part is for the raw casting/forging, and is different from the "part number".

The coolant flow on the 928 engine is very different from the "standard" flow found on most engines. The "standard" way is for the thermostat to block flow to the the radiator when closed - if you remove the thermostat, the engine will run very cold, as all flow will go thru the radiator. On the 928, if you remove the thermostat, the engine will run hot, as flow bypasses the radiator.

John Struthers

There was older gentleman, Dennis, and master of the WUR, who swore there was a 944 thermostat that worked on the older 928's. That particular thermostat with gasket was commonly avalable in most parts stores ten years ago.
I had a failed thermostat at a SharKansas frenzy about 14 years ago. When that puppy fails to open be prepared for either a hard hose, blowback thru the reservior, a blown hose/clamp , or all of the above.
Because the thermostat is part the housing seal you just can't toss it make a gasket and reassemble
(ask me how I know). There were some typically good souls at that Frenzy and we tried everything including filtering creek water.
Eventually one of Arkansas citizens stopped drove me to his hous for a cordless drill then 8 miles to a friends house for a couple long #30 drill bits, and a set of vice grips.
I drilled the non functioning part of the thermostat that wouldnt open with about 6 holes which worked good enough to get me the 700 plus miles back home with no issues.
And once again I thank all those who helped in any way.

John Struthers

Oops!
My 82' Weissach also had that rubber (ring) seal.