What type of sealant to use?

[Tonka7777]

What types of sealant should I use to glue this fitting back into an aluminum intake manifold? Obviously, high temp is needed. I have thread sealant, but there are no threads. Also have high strength sleeve retainer that says it's good to 400 degrees. Whatever they used at the factory dried hard and was not flexible like RTV. I also need to seal up a threaded pipe plug.
Advice is appreciated. Thanks!

Jim

 

[blubuckaroo]

I'd use Permatex II and tap it in. I'd use the same for the plug threads. It is gasoline resistant and can still be disassembled when necessary.
There isn't an application for 400 degree sealant on your intake manifold.

 

[Viperwolf1]

Loctite works for things like that. Use teflon thread sealer for threaded connections. If you really want to fix it just tap it for a threaded nipple.

 

[Steve83]

JBWeld or JBKwik

 

[broncoitis]

Sealant, Silicone, Lube, etc..... Threads????

You know what would be cool, if somehow we could put together a definitive write up about what sealants, silicone's, lubes, etc..... and where they should be use during the assembly of say an engine, tranny, transfercase, axle, etc.....

I know that this is a very broad question but it can be frustrating when putting something back together and you know what to do and are just a little cloudy on the type of sealant/lube to use for the given situation. Maybe this is impossible to do because of all the variations out there but some sort of direction to help clear the clouds would be good for all involved.

What you guys and gals think???

 

[ntsqd]

I think it would be a great idea. I'm surprised that "BillaVista" hasn't covered it already. There are a lot of sealants out there that aren't well known, and the limits of those that are known aren't always known. Things like RTV + gasoline do not mix and play well together. Anyone ever used the real Hylomar (& know NOT to wear good clothes while using it)? That kind of thing.

To the OP, I would strongly consider tapping that and using some sort of fitting. The factory seal is partly based on the tube being a press-fit into the aluminum. Obviously that is lost now. It need not be pipe thread, but to effect a seal with straight threads it is best if you can spot-face around the hole too.

If there just isn't enough material around the hole to tap it (particularly an issue with pipe threads), then I've proven to myself that JB-Weld does work long term with gasoline. Not all epoxies do, for example Miller-Stephenson 907 will peal off like cheap bathtub caulking in about a week. I've used regular JB to seal drilled-passage plugs in carbs that weeped fuel (obvious from the stain and/or the dust around the plug). I've not used any of the other variants of it, no idea if they work as well or not. Clean metal is crucial for a good bond. Do something (grind, file, Dremel, etc.) the face of the hole and the tube to get to bare, new metal just before using JB-Weld.

 

[Steve83]

The problem is that certain sealants can be used alone, OR with certain gaskets, but NOT with other gaskets. For instance; I'm reassembling an engine right now using steel-reinforced nitrile pan & VC gaskets. They're designed to be installed "dry", but the seam between the timing cover & block requires some liquid sealant that contacts the pan gasket. And the tips of the pan gasket that go into the pockets beside the front & rear main seals require something. I used Hylomar blue on the pockets, and E6000 for the TC seam, but silicone could be used in either location. And with other types of pan gasket, silicone would be used on the whole gasket (on the pan side only). Then there are gasket enhancements, like Copper-Coat; and gasket replacements, like RightStuff. And even silicone sealant is available in a wide variety of flavors; common, quick-cure, slow-cure, high-temperature, high-strength, oil-immersion...

So the sheer quantity of options, combinations, and substitutions I think would make a list too impractical, & subject to interpretation & style.