Exhaust Manifold Gaskets/Lifter Tick

[JPVortex]

Hey folks, just replaced exhaust manifolds with gaskets on my 02 Suburban, and they leak still..... Not as bad as before, but they do leak. For gaskets I ran an MLS gasket from a brand called "Michigan Motorsports", they had good reviews, but still both leak already. I did notice when doing the job the head surface where the manifolds sit didn't look the best. There was some pitting here and there, and I wonder if that's contributing to leaking again.

So now I'm in a debate, do I buy Genuine GM MLS manifold gaskets and try those or do I try running the graphite gaskets that came with the manifolds I bought? I feel the graphite could work decent in my spot because it conforms and bends more, which could help with the pitting on my head surface.

Thank you!

 

[Scottydoggs]

copper hi heat rtv might help out with the pitting, but i bet studs vs them crap manifold bolts helps the most.

studs and nuts just clamp so much better.

 

[JPVortex]

copper hi heat rtv might help out with the pitting, but i bet studs vs them crap manifold bolts helps the most.

studs and nuts just clamp so much better.

Thanks! Studs and nuts are already done… haha! Decided that I did not want to deal with bolts ever again lol. Made lining everything up a breeze too.

 

[JPVortex]

copper hi heat rtv might help out with the pitting, but i bet studs vs them crap manifold bolts helps the most.

studs and nuts just clamp so much better.

What would you do for a gasket type? Not sure about using the copper rtv on MLS. Thinking I may try the graphite ones with some spray copper rtv

 

[Scottydoggs]

you really cant do better then the factory metal ones. ive reused them when installing headers on cars.

 

[JPVortex]

you really cant do better then the factory metal ones. ive reused them when installing headers on cars.

Ok appreciate the feedback! Think I'll give the GM Genuine MLS gaskets a try with some RTV.

 

[Scottydoggs]

Ok appreciate the feedback! Think I'll give the GM Genuine MLS gaskets a try with some RTV.

id only do a very light smear of the rtv. might also want to make sure the manifolds not cracked in the body of it, or warped along the flange.

 

[JPVortex]

id only do a very light smear of the rtv. might also want to make sure the manifolds not cracked in the body of it, or warped along the flange.

they didn't look cracked or warped, they are brand new, although cheaper ebay ones. The leaks are very very small.

 

[Scottydoggs]

they didn't look cracked or warped, they are brand new, although cheaper ebay ones. The leaks are very very small.

you could run a straight edge over the flange to check. china made stuff is not always so good.

 

[Marky Dissod]

If you've replaced the gaskets and you STILL have a leak, it's likely there's a surface that needs to be smoothed true.

 

[OR VietVet]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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.