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General TR How does Permatex Permashield compare to Hylomar for sump sealant?

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TuffTR250

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I am preparing to reseal the sump on my TR3 using a paper gasket from Moss. I went to a lot of FLAPs looking for Hylomar Universal Blue but could not find any. I did see they had Permatex Permashield #85420 and on the package it says "compare to Hylomar. Has anyone tried the Permashield on their sumps, and did it work as well as the old Hylomar Universal Blue? Thanks!
Regards,
Bob
 
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I recently used it on the Spitfire oil pan. Unfortunately I had to remove the oil pan again after installation so I can actually answer more about this than I want to admit.

The Permatex sealant is thin-ish and blue. Like Hylomar you can spread it in a thin film using your finger. It skins over fairly quickly. I RTVed the gasket to the Spitfire oil pan and placed it upside down on a sheet of MDF and waited for the RTV to cure. My intent was to bond the gasket to the pan with the RTV acting as both a glue and a conformal sealant to address any flange warpage. The Permatex was applied to the top side of the gasket immediately before the pan was re-installed on the engine.

The Permatex worked fine at sealing the pan. When I had to remove the pan later, both the Permatex and RTV released from the gasket. (I think the gasket had a waxy finish on it that neither the RTV nor the Permatex adhered to). When I dropped the pan the gasket tore and I had to use a new one. The Permatex sealant on the block was easily removed with a razor blade as opposed to the RTV which required a lot more elbow grease to remove from the pan.

Would I buy the Permatex again? Absolutely. It applies easily, skins over and seals like Hylomar, and was easy to remove when I needed to clean the surfaces. I ordered mine from Amazon since it was about 30% less expensive online than in the parts store. The Permatex is not inexpensive but it does cost less than Hylomar.
 
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I was thinking of putting the Permatex Permashield on both sides of the gasket. Today I straightened the sump flanges as best I could but very difficult to get them perfectly flat. In addition, I don't think the block is perfectly flat on the ends where the sealing plates go. So I'm hoping the Permashield will seal both sides of the gasket.

I have used RTV in the past, but I'm really leery of using it on the sump since it can "shred" off into the oil lines. Doug, since you put the RTV on the sump side first and let it cure, the excess could be cleaned up before putting the sump on. But that would not be possible if RTV was used on the top of the gasket and immediately put on the car. So I'm weighing whether to go through the two step RTV/Permashield process or put Permashield on both sides of the gasket. Any opinions from the Forum? Thanks!
Regards,
Bob
 
I also use RTV on the pan side of that gasket, letting sit on sheet of glass to set up well. then hylomar on the side that is against the block.

RTV is a bother to remove when the time finally comes but at least I'll be working at the bench and not on my back under the car.

fwiw - I just ordered a couple of tubes of hylomar blue from this guy -- at about 10 bucks a tube w/shipping seemed a good deal. I think it is the flavor I like [haven't received it yet]:

https://www.ebay.com/itm/2-X-Hyloma...002?pt=LH_DefaultDomain_0&hash=item2c86f043f2
 
Geo Hahn, just ordered some, I will use it when I put the 250 motor back together.
 
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