Exhaust Manifold Gaskets/Lifter Tick

OR VietVet · Feb 15, 2025

Like @Scottydoggs and @Marky Dissod suspect, I too suspect the manifold flange surface. In the beginning, you did not say the manifolds were new or used and where they came from. New....so what. from China is suspect. A nice long straight edge can verify flatness. I have reused exhaust manifolds before but only after checking and double checking with a straight edge or sending to machine shops to have them surfaced. Years ago, the old Dodge engines in the Class C motorhomes, always always always warped the exhaust manifolds. I know yours is not a Dodge but that heat will warp them, just like heat build up on brake rotors.

JPVortex · Feb 15, 2025

Yeah I didn't even really think about it to be honest. The leaks are tinyyy, I mean a very small section. Not even enough to cause a noise, I have another thread about my truck's tick, definitely wasn't exhaust, it's a lifter or something valve train related. Wouldn't have noticed the small exhaust leak if I didn't spray a ton of soapy water while running the vacuum through the exhaust on blow mode. I'm honestly leaning more towards leaving it alone at this point. Its a 200k mile truck with a hell of a lifter tick.

The manifolds did seem of decent quality though, and they had great reviews. However, the head surfaces on both sides looked less than desireable, wish I had gotten pictures.... They're quite pitted across the board where the manifold gasket goes.

If I take it back apart I'll run GM Genuine MLS gaskets with some copper RTV to help seal better, and I will run that straight edge across the manifold sealing surface.

OR VietVet · Feb 15, 2025

JPVortex said:
Yeah I didn't even really think about it to be honest. The leaks are tinyyy, I mean a very small section. Not even enough to cause a noise, I have another thread about my truck's tick, definitely wasn't exhaust, it's a lifter or something valve train related. Wouldn't have noticed the small exhaust leak if I didn't spray a ton of soapy water while running the vacuum through the exhaust on blow mode. I'm honestly leaning more towards leaving it alone at this point. Its a 200k mile truck with a hell of a lifter tick.

The manifolds did seem of decent quality though, and they had great reviews. However, the head surfaces on both sides looked less than desireable, wish I had gotten pictures.... They're quite pitted across the board where the manifold gasket goes.

If I take it back apart I'll run GM Genuine MLS gaskets with some copper RTV to help seal better, and I will run that straight edge across the manifold sealing surface.

If it is in fact leaking because of a warped flange, it will get worse.

JPVortex · Feb 15, 2025

OR VietVet said:
If it is in fact leaking because of a warped flange, it will get worse.

Great.... Always a fun time! Really not excited to pull these things off again. Also not confident that anything is really going to seal it well with the pitting on the heads. Starting to grow more and more tired of this Suburban everyday. I start to think what's the point with it, it's still going to have annoying lifter tick at the end of the day! Lol.

JPVortex · Feb 15, 2025

I will also redo the "vacuum test" once I can, snowing and raining all day tomorrow. While it was running today on the jackstands I tightened up all the nuts a little bit more, couple actually felt a bit loose. I also let it get all warmed up and get a full heat cycle, maybe will help things set a little better. I will report back here with results probably on Monday.

OR VietVet · Feb 15, 2025

The pitting will be taken care of with the copper RTV. Slight pitting would have to be bad right at the gasket sealing area, from side to side, in order to leak. As you continue to work on the Suburban, you will learn to not assume. You have already started to do that or you would have just used bolts instead of studs and nuts. If the Suburban suits your needs and is paid for or owe very little and you like it, then is way better than a large monthly payment and higher insurance. Dealing with lifters is just another well thought out weekend job.

I also encourage you to join the GMT800 Forum, if you haven't already.

JPVortex · Feb 15, 2025

OR VietVet said:
The pitting will be taken care of with the copper RTV. Slight pitting would have to be bad right at the gasket sealing area, from side to side, in order to leak. As you continue to work on the Suburban, you will learn to not assume. You have already started to do that or you would have just used bolts instead of studs and nuts. If the Suburban suits your needs and is paid for or owe very little and you like it, then is way better than a large monthly payment and higher insurance. Dealing with lifters is just another well thought out weekend job.

I also encourage you to join the GMT800 Forum, if you haven't already.

You do have a point there, only paid $3000 cash, no payments on it. Hopefully the lifters can be a 20 minute job

Going to run something to flush the engine, and then may pop a pint or so of Marvel Mystery Oil in there after changing the oil to help clean overtime what a quick flush didn't get. This is what was in the oil pan, so I can only imagine what's in the valve train/lifters. Here's a picture of in the pan when I had it off.

As for the manifolds, I'm going to worry about them soon, but not right away. I need my truck ASAP and a little leaking right now isn't going to stop it from driving. Will be done sooner than later though(especially if I end up pulling the heads to do cam and lifters!)

OR VietVet · Sunday at 12:20 AM

Looks nasty in that pan. Yea, give it a try with the cleaners and see what happens. Can you feel the exhaust leak? Does it get less or go away when completely at operating temp?

JPVortex · Sunday at 12:34 AM

OR VietVet said:
Looks nasty in that pan. Yea, give it a try with the cleaners and see what happens. Can you feel the exhaust leak? Does it get less or go away when completely at operating temp?

Yeah it's pretty gross, hopefully a flush will help clear out whatevers in the rest of the engine.

I cannot feel the exhaust leak from the manifold at all. Only reason I noticed it is because I purposely did a vacuum test, putting the shop vac on blow mode, attaching to the tailpipe, then spraying water at the manifold to head area. Only a tiny little area let out a few bubbles. Before I did the job when there was multiple broken bolts it made GIANT bubbles, like comically large, all over the engine bay. So it's nothing compared to what it was.

OR VietVet · Sunday at 1:39 AM

JPVortex said:
Yeah it's pretty gross, hopefully a flush will help clear out whatevers in the rest of the engine.

I cannot feel the exhaust leak from the manifold at all. Only reason I noticed it is because I purposely did a vacuum test, putting the shop vac on blow mode, attaching to the tailpipe, then spraying water at the manifold to head area. Only a tiny little area let out a few bubbles. Before I did the job when there was multiple broken bolts it made GIANT bubbles, like comically large, all over the engine bay. So it's nothing compared to what it was.

If that is the case. The metal swells a little when heated and may not have a leak till it cools down again.

Exhaust Manifold Gaskets/Lifter Tick

OR VietVet

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JPVortex

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OR VietVet

GMT800 SUV/Trucks

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OR VietVet

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