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Best way to avoid water leaks on the ends of HEMI heads? #2491052
05/02/18 07:31 PM
05/02/18 07:31 PM
Joined: Jan 2003
Posts: 9,670
Lima, Peru
domingo Offline OP
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domingo  Offline OP
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Lima, Peru
How do you do it?

Copper spray silicone on the gaskets?
Beads of copper silicone around water passages on the ends of heads?
Torque in steps?

Has anybody heard of Hylomar Blue?

Re: Best way to avoid water leaks on the ends of HEMI heads? [Re: domingo] #2491090
05/02/18 08:38 PM
05/02/18 08:38 PM
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Posts: 7,471
Minnesota
Hemi_Joel Offline
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Minnesota
Hylomar is good stuff. Are you using steel shim or copper head gaskets? with a good composition gasket, it shouldn't leak.


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Re: Best way to avoid water leaks on the ends of HEMI heads? [Re: domingo] #2491094
05/02/18 08:58 PM
05/02/18 08:58 PM
Joined: Jan 2003
Posts: 9,670
Lima, Peru
domingo Offline OP
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domingo  Offline OP
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Lima, Peru
FelPro 1104 gaskets leaked....twice!

iron megablock, older MP alum heads (pre ebrock), ARP studs.

Just gasket, no sealers, no coatings.

I wanna try something different this time around.

Re: Best way to avoid water leaks on the ends of HEMI heads? [Re: domingo] #2491103
05/02/18 09:16 PM
05/02/18 09:16 PM
Joined: Sep 2003
Posts: 2,175
Duloc
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The Shadow Offline
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Duloc
the right stuff around the passages

Re: Best way to avoid water leaks on the ends of HEMI heads? [Re: The Shadow] #2491116
05/02/18 09:44 PM
05/02/18 09:44 PM
Joined: Jan 2003
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dogdays Offline
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Blue Hylomar is the stuff. You don't need much. Also, it'll stick to anything it gets close to and so your fingers will be blue for a few days. Developed by Rolls-Royce for the jet engines. The Right Stuff sets up and I'm a little leery of it taking load that should be clamping on the gasket. Hylomar never sets up and squeezes out to as thin as it needs to be. A little tube will last a long time. Hylomar is now its own company and there are different goops for different uses but IMHO the blue stuff is the only thing you need to know.
R.

Re: Best way to avoid water leaks on the ends of HEMI heads? [Re: domingo] #2491119
05/02/18 09:50 PM
05/02/18 09:50 PM

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Do you use Hylomar in conjunction with the head gaskets?

Re: Best way to avoid water leaks on the ends of HEMI heads? [Re: domingo] #2491123
05/02/18 09:56 PM
05/02/18 09:56 PM
Joined: Jan 2003
Posts: 1,938
Sonora CA
Mopar_Rich Offline
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Sonora CA
Hylomar is a fantastic product that does well with any style head gasket. But use SPARINGLY. You don't need much.

Re: Best way to avoid water leaks on the ends of HEMI heads? [Re: domingo] #2491131
05/02/18 10:12 PM
05/02/18 10:12 PM
Joined: Feb 2012
Posts: 4,443
Morristown Tn.
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71birdJ68 Offline
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Morristown Tn.
Be sure not to over torque the corner intake bolts. In the service manual.

Re: Best way to avoid water leaks on the ends of HEMI heads? [Re: 71birdJ68] #2491138
05/02/18 10:24 PM
05/02/18 10:24 PM
Joined: Jan 2003
Posts: 9,670
Lima, Peru
domingo Offline OP
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Originally Posted By 71birdJ68
Be sure not to over torque the corner intake bolts. In the service manual.
Yep....but still leaked. I didnt use any sealers though with the 1104 Felpro gasket.

Re: Best way to avoid water leaks on the ends of HEMI heads? [Re: domingo] #2491220
05/03/18 12:23 AM
05/03/18 12:23 AM
Joined: Feb 2012
Posts: 4,443
Morristown Tn.
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71birdJ68 Offline
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Morristown Tn.
What kind of block do you have? Has it been pressure tested? I went through this, and ended up having to use block sealer.

Re: Best way to avoid water leaks on the ends of HEMI heads? [Re: domingo] #2491232
05/03/18 12:43 AM
05/03/18 12:43 AM
Joined: Jan 2003
Posts: 9,670
Lima, Peru
domingo Offline OP
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Brand new megablock. Its seeping coolant from the corners of the head. I can clearly see that upon disassembly.

Re: Best way to avoid water leaks on the ends of HEMI heads? [Re: domingo] #2491348
05/03/18 10:05 AM
05/03/18 10:05 AM
Joined: Jun 2015
Posts: 310
Northeast Indiana
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73DAD Offline
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Northeast Indiana
I used cometics with a 4.5" bore and iron '70 heads. The heads and decks had a normal flycut surface, nothing special. The gaskets had no sealer on them, just torqued them dry. Still good after two years.

(By the way, I'm the guy that bought the megablock from you that was being held by DD back in 2015. Thanks again, I really appreciate it.)

Re: Best way to avoid water leaks on the ends of HEMI heads? [Re: domingo] #2491359
05/03/18 10:48 AM
05/03/18 10:48 AM
Joined: Jan 2004
Posts: 4,866
North of Detroit
HemiDart68 Offline
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Verify the heads are decked flat. I had the famous water leaks on heads of that vintage. Found out they were a few thousandths out of square. Machinist did a clean up cut on them and no more leaks. I would be willing to bet that may be an issue on the other no heads of that vintage as well.


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Re: Best way to avoid water leaks on the ends of HEMI heads? [Re: domingo] #2491360
05/03/18 10:49 AM
05/03/18 10:49 AM
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Posts: 13,319
Marion, South Carolina [><]
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Never heard of an issue leaking coolant at the corners of the head. I have heard of them leaking oil through the gasket at the lower corners where the drainback passages are. I put a little bit of silicone on both sides of the head gaskets at the drainback holes...no leaks.


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Re: Best way to avoid water leaks on the ends of HEMI heads? [Re: domingo] #2491369
05/03/18 11:18 AM
05/03/18 11:18 AM
Joined: Jan 2012
Posts: 2,603
Stuttgart, Arkansas
rickseeman Offline
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I would use copper coat. I know some people say they will seal dry but once when I did that I had a leak and another time I had seepage. Now I copper coat and it stays clean.


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Re: Best way to avoid water leaks on the ends of HEMI heads? [Re: domingo] #2491427
05/03/18 12:44 PM
05/03/18 12:44 PM
Joined: Feb 2014
Posts: 1,695
central il.
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second 70 Offline
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I had one that had an external drip at the front drivers side lower corner of the head and the problem was the intake was too tight. All I did was back off the intake bolts and leak went away.

Re: Best way to avoid water leaks on the ends of HEMI heads? [Re: domingo] #2491428
05/03/18 12:45 PM
05/03/18 12:45 PM
Joined: Jan 2003
Posts: 9,670
Lima, Peru
domingo Offline OP
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domingo  Offline OP
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Thanks for the advice guys....Ill try several things based on all this info and give it a go.

Ill post the results after.







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