Ultra Gray vs.Ultra Black?

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ChuckN

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I am doing some gaskets and I had a tube of black but it is a little old and hard to keep flowing. So I bought some gray, and I kind of liked the way Ultra Black behaved a little better, but maybe it's because is was older. Anyone have a preference of either of these or from another brand?
 

Strick

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82180 Permatex Ultra Black is very close to GM spec. I use it most of the time.

Strickland
 

DoubleDingo

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I've never used the grey. I switched from blue to black when I discovered the blue wouldn't hold back the oil. The black has kept the oil where it belongs, inside the engine.
 

SirRobyn0

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This is what a Permatex rep once told us.
Black and grey are very similar, but grey has more adhesive in it. Also the Grey will handle a little more heat, IIRC black is rated to 500, gray to 700F. At the shop we keep both in stock, but honestly I tend to use the grey more.
 

Ricko1966

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The blue you were using was probably regular blue rtv. Which I think sucks. GM then came out with GMS good stuff,but the ultra Grey seemed just as good so that's what we used for years and I still use damn over 30 years now its never let me down.
 

bucket

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I use Ultra Black most of the time. It works very well. Occasionally I have used the Ultra Gray simply for cosmetic reasons, but it seems to have always worked equally well.
 

82sbshortbed

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Also used black and have used an orange one before but can't remember the name of it. Both worked well.
 

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The blue you were using was probably regular blue rtv. Which I think sucks. GM then came out with GMS good stuff,but the ultra Grey seemed just as good so that's what we used for years and I still use damn over 30 years now its never let me down.
It was. I didn't know about the other stuff. I learned a valuable lesson. The blue even leaked on a diff cover. I didn't have a gasket handy, store was closed, had to drain and refill. Applied the rtv, let it set-up, then bolted it on, not torquing it down or filling up the diff. I waited a day to that, and it leaked in a short amount of time. On the engine it was on the china wall. I think it was honkykong that mentioned the black and grey. So I removed the intake, which I hate doing work twice, sealed up the front and back with the black, and no leaks.
 

Radiohead

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Wasn't ultra gray the original sensor safe material back in the day?
 

bft305

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I went ultra copper for my intake manifold. Probably a little over kill, but doesn’t leak!
 

ChuckN

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Thanks all! I just put my intake on and we’ll see how it goes. According to your glowing reviews, sounds like it will work just fine.
 

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