Hey all. Grew up around the 6.2s/ 6.5s as a child and now I own one.

Just purchased a 91 suburban with 267K miles on it.... CLEAN. no rust great paint, garaged all it's life when it wasn't on the road.

Now for the bad part. when I went to look at it (and buy it) I couldn't get the radiator cap off because the surge line/clamp was stuck up under it and I had no tools with me. So, I bought the thing and drove it home...

The next day I took it down to my shop (started hard) and got the cap off. radiator is 1 gallon low.. Refilled and started the burb. immediatly coolant shoots out of the filler neck.... while it was running I stuck the cap on for about 5 seconds and then removed it. when it was removed I got a huge "woosh"...

Narrowed the cracked head down to the passenger side by removing the T stat and looking at the crossover tube.

When it was removed I had to broken lifters on #6, and damage on cylinders #4 and #6 from water... The pistons are pretty pitted up as well as the head. I got the lifters out and the rollers/cam is good, but the guts of the lifters were destroyed and the pushrods were bent. I assume from HYD locking?

Both cylinders show signs that they were rusty and have surface pitting from rust. I'm unsure how much compression I'm going to lose because of this if I don't repair, but on the upside the engine idles without a miss and smooth, so I think there's enough compression to fire.

I don't know weather to replace the other head gasket while I'm here or not. A friend has a good used head off of a 6.5 diesel for me to use, so I figure I'll swap out my injectors and give it a try. May to a complete engine compression check to see how the two cylinders stack up against the rest.

I know the engine has high miles, but I'd like to see me get some time out of it while I look for a spare.

Any suggestions?

The same friend has a pair of used lifters for me as well, and I can't see for the life of me how this engine maintained 40 lbs of oil pressure with the old lifters all busted up like they were.

 

I can see a cracked cylinder in the last picture at about 7:30-8:00-can't you?

I would say hydro lock pooched the engine.

 

Is your buddies 6.5 a turbo or non? Running turbo heads on a naturally aspirated engine will work, BUT the precups are different and you may suffer some poor fuel mileage. If your looking for a good used set of 6.2 heads I have a set I may part with. If your interested let me know. I'll have to find out about shipping. That could kill the deal.


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*update*

Got a 6.5 head from a friend for a good deal. came off his 93 6.5 diesel.

I was going to switch out precups until I pulled the drivers side head as a precaution in inspect and replace the head gasket. once it was off I was suprised to find it had a 6.5 head already on it (T precups).

So, I decided to put both heads back on with the T pre-cups since my 6.2 cups were cracked all to hell anyway.


Found out through a friend that he knew the guy I bought this burb from, and he also knew that they had filled it up with gas years ago, got about 5 miles out of town when it overheated and quit them.... that's when they had to replace the fuel system.

Could've also been when they cracked the hell out of the passenger side head.

Yes, there's cracks above both intake valves on holes 4 and 6. one is cracked from the intake valve all the way out past the fire ring. it must have been pushing coolant in there like a garden hose.!

Regardless, I used a 3 stone hone on those to cylinders to attempt to put some cross hatch back in the holes and cleaned everything up real good. heads are back on as of yesterday (just haven't had any time to work on it) and hopefully tomorrow it'll be a living breathing machine again.


I'd have taken you up on the 6.2 heads had I known sooner. I'll keep you in mind if this engine doesn't pan out.

On a side note a friend of mine knows a guy that just bought an 86 burb for the wheels and tires and wants to sell the rest of it. it's a 6.2/700r4 setup, so it'd be the same as mine. guy said it ran when he parked it.... $400 sound like a decent deal?

 

$400 is a great deal. If its not all rusted to hell you'll be able to sell parts off of it and get the drivetrain for free. Glad to see your getting ahead of that mess. Previous owner should have told you about it. I take it that the 93 was naturally aspirated since it has the T precups in it already. Should work out good for ya. Good luck and hopefully you'll be up and running soon.


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not sure if the 93 was N/A or not. I thought the "T" cups were for turbocharged units?

I'm not expecting miracles out of this thing, I just hope it starts/ runs and drives well for awhile.

As soon as it's running I'm gonna drop the oil to get rid of any garbage from the failed lifters plus any gasket material or antifreeze that could be present after this teardown.

Got a new set of Kennedy quick head glow plugs for it that I'm putting in at the same time. hopefully this thing cranks right up.

 

Here are my 162 heads off my 6.2. They have 1 dot on the precups.





My 567 heads off my 92 6.5TD. They have 2 dots on the precups.





You can see the infamous crack between the valves on the turbo engine. Although they never leaked.




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yep, I've heard that the 6.2/6.5s commonly had cracks between the valves that rarely leaked. That's why I was so suprised to see the two cracks on this head coming off the intake valves only. the 567 heads I put back on had no cracks at all. both heads have the two dot "T" stamped cups in them. If I had more time and was more confident in how long this engine could last, I'd have shopped around for some 6.2 precups a little harder.

 

got her started up tonight.

ended up pulling the drivers side head to inspect for peace of mind, and found that side had already been replaced with a 6.5 head. so, I put the 6.5 head I aquired on the bad side, and threw it back together. started up and runs good it seems, although at idle I'm noticing some white haze coming out the drivers side bank... don't know what that means exactly.

time will tell if the two bad cylinders I cleaned up will hold up or not. if I bring the engine just off of idle I can feel a slight miss, so we'll have to see how that progresses.

I'll finish buttoning her up tomorrow and take it for a test run.!

 

Good to hear. Hope it all works out. If its running, that's a good sign.


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