Gen 1 Thermostat Housing leaking

[Klurejr]

I noticed a small leak that traced back to my thermostat housing and the seal between it and the plastic part the connects the radiator cap to the cooling system. I pulled it apart of the weekend and did not see anything glaring about it. I was surprized that it is just a rubber o-ring style gasket that runs around the inside of the housing. No cracks in it.

Could the grime showing up around the edges just be to blame? It is a very slow leak, the radiator looked to be topped off when I pulled the cap before starting the tear down.

Here is what it looks like:



Think if I just clean the edge on the inside and the outside and re-assemble it the leak will stop?

 

[Klurejr]

I tested the Thermostat and it is working.

I am guessing it is this O Ring, so I just ordered one from my local shop, should have it in next week.

 

[Klurejr]

I had a few min to take a break from work and pulled the O Ring out and found it was in bad shape, so i am glad I ordered a new one:


I cleaned up the gunk on the Thermostat - here is an in-progress picture to show the gunk:


Cleaned the gunk out of the housing as well:

Put the thermostat back in to see how well it seated up.


Once the new O-Ring comes I can re-assemble and test.