Exhaust manifold gaskets, using actual gaskets or high temp RTV?

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03-04-2025 | 07:14 AM

#21

snapmorgan

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Joined: Aug 2010

Posts: 2,227

Likes: 547

From: Cape Coral FL

I can't stand red RTV smeared everywhere. Gaskets only for me.

03-04-2025 | 08:40 AM

#22

Ryanw10

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Joined: Jun 2020

Posts: 515

Likes: 182

From: Holland MI

The mercruiser manifolds kiss my valve covers on my SBC's with no gasket, and have an air gap with the gasket.

03-07-2025 | 01:30 PM

#23

Steve H

artselectricinc.com

Joined: Dec 2000

Posts: 703

Likes: 27

From: Longview, WA, USA

I have always used metal gaskets from auto parts store for my 42' Sportfish with 502's. 100 plus hours per year, and have never had a failure!

03-07-2025 | 09:15 PM

#24

Tartilla

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Joined: Aug 2019

Posts: 1,201

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From: BC

Quote:

Originally Posted by ICDEDPPL

What`s more likely to blow out, a metal reinforced gasket or some RTV?
Personally I wouldn`t trust just RTV. I do gasket and RTV

The RTV is mostly taking up the micro imperfections of the mating surfaces. I've never had issues with rtv leaking.

An exh gasket is far thicker, and can break down over time and exposure. It can come apart, and now you've lost bolt/stud clamping pressure.

Using RTV you def need to manage it well...less is more.

Last edited by Tartilla; 03-07-2025 at 09:20 PM.

03-07-2025 | 09:17 PM

#25

Tartilla

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Joined: Aug 2019

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From: BC

Quote:

Originally Posted by Ryan00TJ

Always used the high temp red rtv on the manifold gasket side. Dry head side. No leaks. When you remove the manifolds the gasket stays with manifold. No mess to clean on the head side.

This works nicely with rocker covers as well.