Need cooling help please

[Mike Christian]

Unfortunately, the leak is worse now. I suspect that the recess in the thermostat housing that accepts the thermostat is not deep enough. I base this on caliper readings I just took showing the recess is between 0.75 and 0.98mm yet the thermostat flange thickness is .100 to .104mm thick. That could explain why, when I took this off originally, there was no gasket, just a lot of sealant.

I do not have the ability to machine this properly.

I checked and Hillbank has one in stock. I am taking calipers and the thermostat with me to make sure it fits. It is $230 roughly. In two days I happen to be in that area for a little over a week before heading out of the country for two.

Another month will be lost.

 

[Mike Christian]

I was looking at pictures of the Hillbank one I can get, and the quality looks similar to my old one (I.e., not the best). I see a casting void (although smaller). I also see a restriction created by the right angled welding and mating piece.

Does anyone make a high quality unit that right angles to the left seat direction??

 

[DaveM]

I think my thermostat stood proud of the housing just a little like yours. I also had some leakage until I used gasket with Right Stuff. Also are either of the bolts too long? Seems to me one of the threaded holes in the manifold was shallow.

 

[Mike Christian]

Thanks DaveM!

I used right stuff in my earlier attempt and it leaked a little, but still leaked. Now it definitely leaks more.

I think I see the thermostat flange at a slight angle in the recess due to uneven machining.

I will measure the depth of the bolt holes and bolts. I guess I could washer the bolts to remove that concern if they bottom out early...

Thanks again! I am really motivated to end this saga.

 

[Blas]

Maybe 2 gaskets? Or make a thicker gasket yourself.
Blas

 

[Mike Christian]

I am willing to try that Blas! I was hoping the parts would be better quality, but I am interested any solution that will last.

I could see buying two FelPro gaskets, trimming one for a larger thermostat hole to clear it outer edge (if that can be done), and stacking them with a thin sealant.

Thanks!

 

[David mono]

Quality of the housing could be better, they should be casting them.

 

[Markus]

The gasket of the thermostat has a fairly simple shape.
You could make your own from sealing paper - they are available in different thickness. Just make sure you buy good quality.

https://www.amazon.de/-/en/Elring-Abil-Sealing-Paper-Approx/dp/B097RMSZCP

Abil N DIN A4 5 Stück Dichtungspapier, 1,35 €

Abil N wird vorwiegend zur Abdichtung gegen heiße und kalte Öle, Fette, Kraftstoffe und Kühlwasser mit Korrosoins- und Frostschutzzusätzen eingesetzt.

www.online-dichtungsshop.de

 

[Mike Christian]

Thanks Markus! I am going to do something like a double or thicker gasket as a backup if the thermostat housing Hillbank has doesn't look any better than the one I already have.

I agree David mono. Why aren't there more options out there? Or are there?

 

[Jean-Marc]

Now that you know the origin of the problem, you may also cut a thin aluminium sheet (easy with a dremel) that will compensate the thickness of the thermostat housing and then you stack it between 2 gaskets + silicon compound on the gasket.

 

[Lee Patterson]

Mike - so your previous post said you assembled the part and then let it sit overnight before applying torque to the bolts? why - put the assembly together and tighten it down. Then let the RTV dry. How is it leaking? - you put the system under vacuum and it would not hold? Can you explain how you know where it is leaking? The torque value for those bolts is only about 15 ft. lbs.

 

[Mark H.]

Maybe this might help? If you need a bleed port just drill and tap for a fitting. https://www.billetspecialties.com/Store/All/Item/ford-small-block-thermostat-housing/?SKU=90620

 

[Mike Christian]

Jean Marc, I like this idea! I think I will try it or the stacked gasket variant!

Lee, I didn't say that quite right. The housing design is such that the right screw is slightly behind the large hose outlet. I tightened both screws with Allen wrench the best I could. I wondered if that clearance issue was keeping me from tightening it further, so the next day I went and got a ball tipped Allen. I was able to tighten that screw a bit more. The main leak could be easily heard and felt near the other screw...the one with direct access. After measuring, I now know this is the area of the housing with minimal depth (where the thermostat sits highest above the housing flat surface. That is why I am focusing on that area now.

Mark H. - I like it and that (or something like it) is now Plan B.

Off to other places...I will report progress in about a month. Thanks again! My anxiety level is back down thanks to you all!

 

[Lee Patterson]

Is the bolt bottoming out on that side?

 

[Mike Christian]

Bolts measure about an inch in length not including washer thickness. The hole depths are about 1 inch. The thermostat housing is about 0.4" thick. Then there is the gasket, etc. I think I can rule that out as a cause.

 

[Randy V]

Bolts measure about an inch in length not including washer thickness. The hole depths are about 1 inch. The thermostat housing is about 0.4" thick. Then there is the gasket, etc. I think I can rule that out as a cause.

Check that the threads go all the way to the bottom of the holes. I’ve been bit by that snake before…

 

[Mike Christian]

Great point! I will screw the bolts all the way in before starting this effort back up when I return.

 

[Mike Christian]

I actually had time to screw the bolts in and measure. They don't bottom out but remain about 8mm off. Here is a simple drawing I came up with so when I get back from traveling I don't have to start over.

Right now I think a FelPro gasket with hole widened to clear the protruding thermostat flange sandwiched to an unmodified FelPro is the first thing I might try. I would use thin layers of that Permatex Thermostat Sealant on both sides of the two gaskets.

 

[Bill Kearley]

Don't forget to drill a 1/8 hole in your thermostat and install it hole up !!

 

[Mike Christian]

Yes! This thermostat version has a small hole already. I am thinking of enlarging it...