Hi-temp block sealant or standard? How hot does a block get?

[cheburashka]

Fastenal carries a product called "Lab Metal" which they say adheres better than JB Weld and has better flexibility. I'm planning on trying it on my cracked 3.0 block. I'm wondering whether to use the high temp or the standard. The standard is rated to 350 degrees and needs no heat to cure. The high temp is rated to 1000 degrees, but it needs one hour at 425 degrees. I don't think there's any way I can keep the block at 425 degrees for an hour. The crack I'm fixing is part of the water jacket, so the inside of it should never get much higher than 300 degrees. Then again, it's right under the manifold, so I'm not absolutely sure it will stay that cool. Any recommendations?

 

[TitusAdronicus]

Re: Hi-temp block sealant or standard? How hot does a block get?

The block will NEVER reach 1000 degrees, if it does, i think there would be more problems than your sealant failing. For me JB Weld is tried and true, i know its considered a "temporary" fix, and maybe it is, but I have yet to have it fail me.

 

[Coors]

Re: Hi-temp block sealant or standard? How hot does a block get?

I used it on a car for body work. That is some runny stuff..

 

[cheburashka]

Re: Hi-temp block sealant or standard? How hot does a block get?

For me, the question isn't whether it's going to hit 1000. It's whether it's going to get above 350. I can't see any way I'm going to be able to get the hi temp stuff to cure at 450, so it's either the low temp stuff, or JB Weld.

As I think about it, after shutdown there's going to be non-circulating water in the block, so there's a good chance it will get very hot. I don't know whether this stuff is going to work.

I know JB Weld is "tried and true" but the truth is that almost everyone who has tried it has had leaks. I'm wondering whether the Lab Metal might last a bit longer than JB Weld.

Has anyone had better results with any other brand of putty sealant?

 

[Bondo]

Re: Hi-temp block sealant or standard? How hot does a block get?

Water Boils at 212*,..........

An engine Block will Never see the High-side of 300*............

If it get's That Hot,......... You've got Alot Bigger Problems by then.............

 

[Robj]

Re: Hi-temp block sealant or standard? How hot does a block get?

I agree with Bond-o. The crack you are fixing is probably on the water jacket, and it should never reach much above 212, max 250 degrees. The lower temp stuff should be OK.

Have a great day,

Rob.

 

[TitusAdronicus]

Re: Hi-temp block sealant or standard? How hot does a block get?

I think the reason the repair fails is bad prep. the surfaces need to be CLEAN NO OIL, you need to clean way around the patch area. That is key to JB Weld