Engine flush, with the heads removed

[Junker88]

I'd like to know what happened.....LS engines aren't known to blow head gasket even after a overheat event.

Do not attempt to surface the heads yourself, Fel-Pro has composition head gaskets if you're worried about surface finish.

It was gasket failure as far as I can tell. Heads are 862s, no cracks in the usual spots with the 702s. Though it's an 02 it still had graphite gaskets and no tab on the block

Reason for pulling the heads was coolant loss, very slowly. I had to buy dye and finally got a faint spot at the passenger side head, right at the front. Once I got them off it was actually the driver side that was worse. There was slight buildup on tge valve cover and the upstream faces of the 02 sensors were slightly white.

Spark plugs looked ok, oil never had any indication of water, coolant none of oil.

I dont have a pic but the gaskets were corroded at the coolant galleries

The heads are still perfect tly flat and it never overheated in the 15 year known history. Mileage is 1/4 million

 

[Junker88]

I'd like to know what happened.....LS engines aren't known to blow head gasket even after a overheat event.

Do not attempt to surface the heads yourself, Fel-Pro has composition head gaskets if you're worried about surface finish.

Brief history, 15 years, maintained well. 1/4 million miles, mostly ours (dads truck, mine now) was losing coolant ridiculously slowly. Used dye to find leak passenger side front on the deck

So I take them off and it looked like gasket failure. Driver side was actually worse, driver valve cover sad slight buildup and o2 sensors has slight white staining one side. All pistons thin coolant layer, 7 of 8 spark plugs looked fine.

I cant see anything else wrong, being an 02 it actually had graphite gaskets but didn't have the tab. Bit of an oddball. The corrosion was at the coolant galleries but only the top so possibly the sealant failed. All bolts broke free with about the same torque except 1 in the far rear bottom corner. Still, the heads are perfectly flat. I had to measure down to 1/2 thou to find variances and at that point its irrelevant

I actually already bought a fel pro MLS kit, is that not going to work without machine resurfacing?

 

[clinebarger]

If you have "Notched" heads.....You must use composite/graphite head gaskets!!!

 

[Junker88]

Couple examples of me cleaning a LS/LT cylinder head surface with razorblades & brake clean.....

^^ thought I lost the upper reply sorry to double post, second post is complete

That is some nice work mate, can you install them like that? You say cleaning but idk if that's what you mean by resurfacing aswell

Took alot in the past few weeks, guess I should have taken another week to figure it out.

 

[Junker88]

If you have "Notched" heads.....You must use composite/graphite head gaskets!!!

Oh yeah, I knew that much. Threw me for a loop because it had composite gaskets but no notch

 

[Junker88]

Oh yeah, I knew that much. Threw me for a loop because it had composite gaskets but no notch

Couldn't figure out what everyone was on about, there is no tab, notch w/e

 

[Junker88]

Couldn't figure out what everyone was on about, there is no tab, notch w/e

It's an lr4 if that makes a difference

 

[clinebarger]

You could have those heads surfaced & run late MLS gaskets, But not much of anything to gain from it. Run Composite/Graphite gaskets.

I AM concerned about all the cleaning that's been done with a bristle disc!

 

[Astro14]

https://static.nhtsa.gov/odi/tsbs/2019/MC-10163260-9999.pdf

Please read this bulletin.

Look at the picture in the bulletin.

See anything familiar?

 

[Junker88]

You could have those heads surfaced & run late MLS gaskets, But not much of anything to gain from it. Run Composite/Graphite gaskets.

I AM concerned about all the cleaning that's been done with a bristle disc!

Don't take it the wrong way but, why?

I've had people say that I ruined it, that they wear down the edges of the combustion chamber but I can't get standard feeler gauges to slip anywhere

Is it the abrasive particles? Is the surface finish more akin to the surface of the moon?

I cant get a technical answer for this anywhere

 

[Astro14]

Don't take it the wrong way but, why?

I've had people say that I ruined it, that they wear down the edges of the combustion chamber but I can't get standard feeler gauges to slip anywhere

Is it the abrasive particles? Is the surface finish more akin to the surface of the moon?

I cant get a technical answer for this anywhere

Because GM specifically, carefully prohibits the use of that exact kind of pad in the TSB I linked.

It starts out saying: "Notice: Do not use abrasive pad/bristle devices to clean the gasket surfaces of any engine, transmission, transfer case and axles as well as any other component that contains lubricant."

Read the bulletin I linked for more detail, but yes, abrasive particles get in the engine and cause damage. Yes, you have damaged the sealing surfaces of the block, and the heads. You can't get a feeler gauge in there, but those scratches have changed the sealing surfaces.

 

[Junker88]

https://static.nhtsa.gov/odi/tsbs/2019/MC-10163260-9999.pdf

Please read this bulletin.

Look at the picture in the bulletin.

See anything familiar?

Perfect. Clear as day. Thank you. I'll be able to polish that out and clean it up proper by the weekend.

Only thing that still baffles me is those rubber bristles removing that much material. It's just, you'd have to be blind not to notice that

The scratches though I can deal with, the abrasive particles have me a bit concerned though

 

[clinebarger]

The material off the pad alone contaminates the engine, You took it to another level by cleaning the piston crowns.

And to be honest....You can probably get away with it on a LR4/LM7 Iron LS engine.

 

[Junker88]

The material off the pad alone contaminates the engine, You took it to another level by cleaning the piston crowns.

And to be honest....You can probably get away with it on a LR4/LM7 Iron LS engine.

The way she goes I guess, no money, no mentor, just what I know vs what I don't.

Again, thank you for helping me, I can recover from this still. These scratches though, as I polish down. Unbelievable. I hate those things now. And I thought I was taking it easy....live and learn

As for the cylinders, I'll figure something out. Have to, can't afford not to

 

[andyd]

IIRC, I used a wallpaper scraper with a sharpened edge, It wasn't an overheat , just burned exhaust valves in #4.The only precaution I took was to back off the head bolts in 3 stages. Whatever, it was a driveway job.New parts were limited to a gasket set, 2 exhaust valves and set of valve keepers. It squeezed another 60K miles out of a '99 Honda CRV. It was not a professional job by any stretch. but I considered the job a success

 

[thastinger]

I really appreciate you mentioning that as I was ready to go for it. If I understand correctly you can get an RA under 50 on aluminum with 220 grit (saw some chart)

Would that be appropriate to use on a sanding block? Sand until the machining lines are gone?

Random orbit sander with 2000 grit wet/dry paper?

What would you use, I probably have it

Thank you

I think it is beyond the scope of home repair to try to surface cylinder heads, 99.98% of people would F that up trying to do it. I would leave the surface like it is and run graphite head gaskets instead of MLS gaskets.

If it was the end of the world and no machine shops were around anymore, you could do it on a perfectly flat piece of thick stone and single sheets of sandpaper that were larger than the head itself, you would go in figure 8s working your way up from 220g to 600.

 

[Junker88]

I think it is beyond the scope of home repair to try to surface cylinder heads, 99.98% of people would F that up trying to do it. I would leave the surface like it is and run graphite head gaskets instead of MLS gaskets.

If it was the end of the world and no machine shops were around anymore, you could do it on a perfectly flat piece of thick stone and single sheets of sandpaper that were larger than the head itself, you would go in figure 8s working your way up from 220g to 600.

I'm not 99% of people, I'm bloody insane, absolutely bonkers, completely mad even

 

[Junker88]

I've since filed a heatsink flat and begun polishing the head. Afterwards I'll rinse it with a parts washer I made with an old receiver tank filled with acetone that I hooked up to my compressor. I've also sharpened an old planer blade and will use this to scrape the deck flat.

I can't accept that this task is impossible, let alone remotely difficult. I am insane

 

[Junker88]

The material off the pad alone contaminates the engine, You took it to another level by cleaning the piston crowns.

And to be honest....You can probably get away with it on a LR4/LM7 Iron LS engine.

Well boss, I've been at this on and off all day and this is as far as I got. I'd run composites but I don't think I can send the gasket kit back so I figured I'd just resurface them

Believe it or not I do know what I'm doing but the further I go the flaws go just as far. Should I call it quits and have them sent out or are these fel pro gaskets really designed "for the repair industry"?

If I'm close then that's all I need to know. Yes it is still flat. That's the only thing I'm 100% positive on

 

[Junker88]

Well boss, I've been at this on and off all day and this is as far as I got. I'd run composites but I don't think I can send the gasket kit back so I figured I'd just resurface them

Believe it or not I do know what I'm doing but the further I go the flaws go just as far. Should I call it quits and have them sent out or are these fel pro gaskets really designed "for the repair industry"?

If I'm close then that's all I need to know. Yes it is still flat. That's the only thing I'm 100% positive on

If there's flaws on the sealing surfaces in yellow then everything has to go down below the lowest point of those flaws, correct? I'm just trying to learn right now. I've accepted that I might have to fork out more money I don't have