Kevin in Atlanta

I replaced the inner thermostat seal about a year ago. This week I took a look at it while disassembling the engine to replace the head gaskets. It is worn, the edge is not smooth and shows a lot of wear for a year of use.

Thoughts?

Ducman82

pictures?

Mrmerlin

its a good idea to swap it out if the edges look deformed.
this could be also a issue with the type of or age of the coolant used.
I use Zerex Go-5 coolant and distilled water

Kevin in Atlanta

I am converting all my 928s to Zerex Go-5 coolant and will make it an annual maintenance checkup.

Sorry no pictures. It's being powder coated. I'll post upon its return.

dr bob

You get to make a judgement about how well it's able to seal against the rear disk on the thermostat. Until a few years ago, I was in the "thermostats never fail" camp. After replacing the rear seal (pretty worn) and seeing virtually no improvement, I finally replaced the thermostat on a whim and suddenly had correct temps again. So at this point, and especially after seeing your post about the failed rear seal and the rusty ring in the water pump, I'm ready to suggest new thermostat and seal together at every TB/WP replacement.

Don't powder-coat the insides of the water bridge. When (not 'if') the paint starts to flake off, it will end up in the bottom of the block and the radiator. Block isn't so bad, in the dead zone. In the radiator, not so good.

davek9

I was going to ask what type of Coolant you are using, some of the newer coolants seem to eat up the rubber bits.

The Forgotten On

Just use Zerex G05. That is what most of us have been using for a while.

dan-bra77

mine was just "missing" when I went to replace the thermostat! Was found yesterday during the water pump change!

Chris Lockhart

Wow, that's not good. Glad it didn't do any damage.