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1967 Mustang Convertible
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Discussion Starter #1
I will be installing a new cam, heads, intake, etc.. here in the next week or so. Usually I use blue rtv for timing cover, water pump and thermostat housing just a small skim on the gaskets. Then I would use the black for Intake end seal, oil pan, and valve covers along with the appropriate gasket. I have never used the grey but seems to say for high vibration. So what do folks typically use now days. Is grey better for some of these like around the water ports of the intake gasket?
 

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As far as I know....All of the Permatex "Ultra" Series Sealants are all the same except for their color. If you have a '65, Use Permatex Ultra Black, If you have a '66 to '73 engine, Use Permatex Ultra Blue. It's as simple as that...

Head Gaskets use a completely different type of Sealant if you're using any at all...so make sure that you use a sealer that's meant specifically for Head Gaskets.

:eek:) Tony K.
 

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I'm kinda partial to the Ultra Gray , but I like Aluminum stuff and it kinda blends in better
 

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Just some guy
67 coupe, 69 Sportsroof, 86 hatchback
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I consider using RTV and gaskets together as an incorrect usage of both products. Installations like timing covers and oil pans require gaskets and only a small "dot" of RTV in strategic corners. It's not just me saying so, it's like every service manual (and Alldata, etc) ever.
One of the reasons not to do so is you will notice when you install a gasket that way, you get a "string" of RTV that squeezes out, right? After it cures you can often peel that ugly snot string off. Problem is that there is a matching string on the inside and it doesn't take much for it to let loose either. And then it goes somewhere. Like the intake side of you radiator where it happily clogs up some water passages. Or in the oil system where it sticks in the oil strainer. I've pulled an oil pan where an RTV fan had used so much on all the gaskets that RTV was hanging out of the strainer like spaghetti. And all the engine bearings were destroyed does to oil starvation. You don't want to be that guy.

That said, sure, RTV is very useful. Just use it with discretion. And don't "paint" gaskets with it. Lately I favor Ultragray, because of how it blends so well with alloy components. Ultra copper is great for high heat applications and looks terrible used anywhere else. Moto Seal is some very thin viscosity gray that I rarely use but is handy sometimes.
I DO use Permatex's Aviation Gasket Sealer on gaskets (with discretion). It works very well around water ports. In particular that left front water port of the intake. Also a paint around the water ports of the timing cover and water pump. It also doubles as a thread sealer on those water pump bolts that go into the block and are prone to corrode. For some reason it does NOT work at with ATF but is pretty resistant to fuel. Nasty difficult to clean up when it squeezes out so a light coat is best.
 

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Ford didn't use RTV when they built them and they stayed "leak free" for years.
 

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All said above, plus use Permatex thermostat and water pump grey for any area that coolant will touch, it’s the best.

Just a super light schemer around the bolt holes. Otherwise, NO RTV, ever !

Z

PS. any don’tbe tempted to put RTV on a head gasket.that’s a sure recipe for a blown head gasket !!!
 

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1967 Mustang Convertible
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Discussion Starter #7
Thanks guys. I have never had good luck with the Cork intake end seals. I have usually used Black RTV. But I won't use it in any other spots. The mating surfaces after 50 years are not as flat and true as when they where first built but I will try without any RTV anywhere hopefully it will be leak free after replacing all the parts. Just what I noticed last time I replaced my water pump.
 

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Just some guy
67 coupe, 69 Sportsroof, 86 hatchback
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I like that plan. I will "flat file" any surface I suspect. These days that's about everything as most of it is either as old as I am or carelessly stamped out of some Asian sweatshop. On the older stuff my experience is that pitting can be more a problem than anything else. If pitting is really bad, every rule has an exception, and I might paste a little RTV in there to fill the pits. Very little. As good as Aviation Sealer is with helping gaskets stay sealed, it's not thick enough to help with more than very minor pitting.

I despise cork end gaskets. I "paint" the intake with a light coat of RTV AFTER laying down big fat beads of it on the block. Then assemble before the thin coat can dry. This makes a seriously leak proof seal. I have to take a razor blade and cut before I can remove an intake installed this way. Key is both sealing surfaces must be perfectly clean and dry before starting. RTV does not stick to oil. Because the size of the gaps we are sealing on the intake ends, there's no formation of "strings" to speak of.

Another issue with coating a gasket with RTV is that is can allow the gasket to "squirm" out of place. Most OEM's (notably Ford and GM) have had issues with that happening with originally coated gaskets (those went out of fashion REALLY quick) and even the newer gaskets formed solely of silicone. (Notably Taurus 3.0 pan gaskets for example.)
There are "print-o-seal" gaskets that come with a center stripe of silicone on them. These work OK but don't resemble anything a DIY person can reasonably do.
 

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I'm partial to black RTV, unless on aluminum areas like mentioned already or sealing crankcases on small engines where most of those products are grey. Any other colors just look tacky to me.
 
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