Wet Bolts... which ones?

Rockett · Nov 17, 2019

Big block with OEM heads.... which exhaust manifold/header bolts are “wet”? (I have all bolts; no studs).
I guess RTV is recommended on those threads, but is it absolutely necessary? (I reinstalled my headers without RTV on all the bolts.)
Are *all* the bolts “wet” or just certain ones?
Rick

Kern Dog · Nov 17, 2019

The two outer bolt holes are open to the coolant passages.
No, RTV is NOT the recommended sealant!

Big Bad Dad · Nov 17, 2019

Thread sealant or maybe pipe dope. NOT silicone....

Rockett · Nov 17, 2019

Kern Dog said:
The two outer bolt holes are open to the coolant passages.
No, RTV is NOT the recommended sealant!

The two outers at each corner (2 x 4 = 6 total) ??
Is sealant use on the threads a *must*?

mr. b · Nov 17, 2019

all the holes are wet on a big block

Kern Dog · Nov 17, 2019

Shoot, Mr B may be right! I have had aluminum heads since 2003 so I thought only the outer bolts were into the passages.
By that, I mean OUTER. One per corner....But now you have me wondering about that!

old guys rule · Nov 17, 2019

Rick Rockett said:
Big block with OEM heads.... which exhaust manifold/header bolts are “wet”? (I have all bolts; no studs).
I guess RTV is recommended on those threads, but is it absolutely necessary? (I reinstalled my headers without RTV on all the bolts.)
Are *all* the bolts “wet” or just certain ones?
Rick

Most are wet bolts coat them all to be certain

Rockett · Nov 17, 2019

What’s the recommended sealant material for the threads??

dadsbee · Nov 17, 2019

Permatex thread sealant or Loctite PST-592.. RTV is for roof flashings !

Lefty71 · Nov 17, 2019

The closed chamber '915's I just did this fall were wet, every single one. I used Permatex as (I do believe) was recommended by KhryslerKid and had no issues from the get-go. :thumbsup:

cryplydog · Nov 17, 2019

Non hardening pipe dope, I use Rector Seal Brand from the plumbing shop. there are also other brands that are just as good.

multimopes · Nov 17, 2019

I recall a fairly recent thread that recommends studs over bolts due to a shoulder on the tapered studs that help seal against the head.

SublimeSixpack said:
I agree with using studs rather than bolts. The proper studs will have a bit of a shoulder on them and that helps in sealing. FWIW I've had good results with Permatex High Temperature THREAD SEALANT. https://www.permatex.com/products/t...nts/permatex-high-temperature-thread-sealant/

In my case, I have a mix of bolts and studs on my 440. Bought it that way. I do get a tiny bit of weeping from the bolts in very cold weather! Must be true!

33 IMP · Nov 17, 2019

mr. b said:
all the holes are wet on a big block

Not necessarily. Depends on which casting. 906s on my 440 are all wet, two sets of 286 heads, all four have only the first and last holes wet.

khryslerkid · Nov 17, 2019

dadsbee said:
Permatex thread sealant or Loctite PST-592.. RTV is for roof flashings !

And rain gutters! :thankyou:

Just do all of them. I did just four corners and had the second one back on the passenger side start to leak.

Use Permatex #2 You can't go wrong. The stuff is older than me.

JimCoronette · Nov 17, 2019

https://www.permatex.com/products/t...d-sealants/permatex-thread-sealant-with-ptfe/

khryslerkid · Nov 17, 2019

JimCoronette said:
https://www.permatex.com/products/t...d-sealants/permatex-thread-sealant-with-ptfe/

That's a Teflon mainly used for pipe and hydraulic fittings. Not saying it won't work.

I've been useing the Permatex #2 from day one. It's what it was originally designed for, water jacket bolt sealant. Removing bolts from exhaust manifolds that I had installed myself was proof enough for me. It was still somewhat pliable after many heat cycles and it never leaked.

62440 · Nov 20, 2019

I had the 4 outside bolts on my 906 heads leaking. I cleaned the threads with brake cleaner until they were squeaky clean and let dry for a day. I replaced the bolts with studs and slathered Permatex high temperature thread sealant on all threads and they still leaked a bit. A "Old Mopar Guy" from my parts store recommended "Aisin" Semi-Drying Liquid Gasket Gray and no more leaks. It's OEM Specified and low and high temperature recommended for pretty much anything. I don't know how available it is. He had to special order it. Hope that might help

Moparwrench · Nov 20, 2019

Kern Dog said:
The two outer bolt holes are open to the coolant passages.
No, RTV is NOT the recommended sealant!

All holes go into coolant- I use permatex hardening- #1 holds the bolts tight too & I've been doing this for over 30yrs

33 IMP · Nov 20, 2019

Again, Not all heads have all the holes going into water jackets. Most aftermarket aluminum heads are dry, earlier oem heads only have two bolt holes into the water, the very end holes on each head. I should know I have two sets of heads that way.
I will admit that most on this forum are dealing with later heads, and they are open to water, but if someone assumes theirs are open, loads up the bolt with sealer, and then puts it in a dry hole, problems can result.
Best procedure is: pull one bolt at a time, see if it is a wet or dry hole, if it is wet, seal it!

Rockett · Nov 22, 2019

So I re-pulled all my bolts on the header that I had previously removed.
ALL were wet bolts.
Resealed with Permatex High Temp Sealer... followed the instructions: do not use on first 2-3 leading threads; apply to only 1/4 turn of threads (not "all the way around" the bolt).
Worked great!

Wet Bolts... which ones?

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