davidpowell

Hi -

I have an '85 S2 4.7l.

I am changing the thermostat and I am a bit confused. My old thermostat didnt appear to have the expected 'o' ring between the thermostat and the housing (by housing I mean the short section of alloy connected to the rubber hose).

Instead it had a hard gasket the engine side of the thermostat - between the thermostat and the engine block.

There was also the expected smaller diameter, but thicker, rubber doughnut inside the block (which also needs replacing).

My new thermostat just has an o ring, which would fit the housing/rubber hose side of the thermostat; this seems to match up with schematics.

Has anyone had this hard gasket on the inner surface of their thermostat? Is it a porsche variant, or perhaps the PO fitted the wrong type of thermostat?

My car was running a little too hot, and as the hard gasket would have pushed the thermostat out from the block by a few mm, so it didnt come into contact with the doughnut so well, would that all tie together as the cause???

Any help appreciated!

DAvid

WyattsRide

David,
Here's good thread with pics. Not sure if your 4.7L is the same though. You may not have the inner seal. My 85 5.0L does.

https://rennlist.com/forums/928-foru...ng-gasket.html

SeanR

Where did your purchase it?

davidpowell

I am in the UK - it is RHD.

davidpowell

Thanks for the links to the photos - I am a bit confused by them though: the thermostat on the left has a thick flattish gasket with it, looks a bit like my old one did.

The thermostat on the right has an O ring like my new one.

Do you know what the author is trying to show by dispaying the pair of them? Or where the thick gasket on the left is placed - outside or inside the thermostat??

soontobered84

David,

You should be using both: the flattish rubber covered seal on the engine side of the thermostat and the O ring between the cover and the thermostat.

WyattsRide

The picture shows the old thermostat and gaskets on the left. The old inner seal has a metal ring and rubber seal. Usually the rubber is deteriorated. The metal ring needs removed for the new inner seal to fit. The new ones on the right.

The small seal on the bottom is the inner seal. (between the engine side and the thermostat. Shown installed in the second pic) You may not have inner seal for your engine. The larger seal is between the thermostat and the bolt on housing. (shown in the third picture)

The Thermostat, inner seal and O-ring are sold separately. If you got a o-ring with the thermostat, it may not be the correct one for the 928.