Thermostat replacement gasket question

[WPVT]

I am replacing the thermostat in my 1954 218 engine. Originally there was a thick paper gasket. I used a new gasket and non-hardening Permatex. It leaked profusely.

Given the inevitable irregularities in the inlet neck and block mating surfaces, is silicone the only way to go ?  With or without the gasket ?

Thanks.

[Jeff Balazs]

Did you use sealer on the bolt threads? If not that is probably where you leak is coming from. Otherwise Check the mating surfaces. Make sure the thermostat is properly seated below the gasket. Permatex works just fine in this application. And Yes you need to use the gasket.

Hth, Jeff

 

[WPVT]

Thanks Jeff. Good point on the bolts. On removing them the second time I noticed they threaded right into the water jacket. 

In redoing the job, I set the aluminum housing onto a flat machined surface to check it out. There was more deformation than a gasket could ever compensate for, so I did a little flattening with a mill file. Fingers crossed for a leak-proof job this time around.

[Jeff Balazs]

You have an aluminum housing? That is certainly not an original type part. Might want to find a better replacement.

Jeff

[WPVT]

12 hours ago, Jeff Balazs said:

You have an aluminum housing? That is certainly not an original type part. Might want to find a better replacement.

Jeff

I'm pretty sure it's original. This is a 1954 C-1, and I seem to remember that some changes were made in the housing around that time.  

[CO54]

My 54 C-1-C had a steel thermostat neck that was rusted out.  As you mentioned in your t-stat thread, my truck doesn't have a heater either.  It was just a straight neck coming out of the head.  

[Dodgeb4ya]

Never have seen an aluminum T- Stat housing as original equipment on a MoPar  flathead. 

 

[chrysler1941]

Always wondered why people use gasket and silicone. Before it was invented, gaskets where always enough. 

[WPVT]

On 8/30/2021 at 10:25 AM, Dodgeb4ya said:

Never have seen an aluminum T- Stat housing as original equipment on a MoPar  flathead. 

 

I guess we'll never know. It's painted the same as the engine, which has never been rebuilt, so I assumed it was original. I don't know how it was manufactured. The flange is 3/16-1/4 inch thick, while the neck is thinner, and formed, not cast. I guess the advantage would be that if you over tighten it, the flange tabs bend instead of break. I filed the face flat, used some restraint while tightening, and now it works fine. This is a straight upright neck, no heater bypass, etc.

 

[WPVT]

On 8/30/2021 at 3:03 PM, chrysler1941 said:

Always wondered why people use gasket and silicone. Before it was invented, gaskets where always enough. 

In my case there is some pitting on the mating surfaces, and they aren't perfectly flat anymore. There is more irregularity than paper and gasket cement could seal on its own.

Otherwise, I agree. I always like to stick with the original engineering.