I have a 97 4x4 blazer. It's got just under 200k on it and still runs great. However Im pulling out both motor and trans so I can rebuild the trans and re gasket the engine. But I'm thinking about blowing apart the engine and I stalling new rod, main, and cam bearings along with honing the cylinders and installing new rings. I'm not sure how the cylinders look yet but I know the compression in all 6 is almost at factory new specs and the motor burns no oil. I'll also be installing remanufactured heads as well. Any thoughts or comments?

 

This is a tricky one.

IMHO I would not do the engine except if it was leaking. Then there is the issue with the LIM.

If you do that and the heads are tight and not leaking it could be an easy fix and the engine is back and running. Money saved for now and transmission rebuilt - or bought and you keep the one that comes out of your Blazer for home rebuilding.

At 200k it will most probably have built a ridge already on the cylinders. As soon as you get to the heads and the block it will be a complete rebuild, eventually 0.030 over. As long as the engine does not show ANY sign of need I would keep it that way and save the money for a rebuild later.

Other opinions?

 

I wouldn't bother if it's not burning any oil at all and oil pressure is good. I just rolled 200k on my 04 and I'm MAYBE 1/2 quart low between oil changes and I don't worry about it at all. Still runs great and has great compression readings, oil pressure is steady at 30-35 at idle at operating temp.

 

Kinda what I was thinking. Might just re gasket and let it be for now and go buy a junkyard motor and slowly rebuild it. I can do everything myself except for machine work so it won't cost too much. I know I'm gonna re gasket this motor and throw in new injectors, iac, plus wires could and plugs. I'll probably get another 60k out of it but it might be a good idea to have a backup motor ready just in case

 

A head gasket re-do isn't a terrible idea if you're willing to dig into it. They're what usually kills a 4.3l, and that's usually because the intake gasket fails first, leaks antifreeze into a cylinder and burns it off, the engine overheats from lack of coolant, then the headgasket lets go and/or warps/cracks a head... The lower intake gasket is really the only achilles heel of the 4.3l... If well maintained (proper oil changes and not extremely hard on the motor) the bearings, cylinder walls, and rings should easily last 300k+

 

I'd really love to throw a cam kit in it and some roller rockers too but I don't want to do that to a 200k motor. I'll probably do the timing set and water pump as well while I've got it out. Gotta make it as fresh as possible so I can depend on it.

 

These motors last forever..
I have seriously seen some at the salvage yard with 500-600k miles.

 

If it ain’t broke don’t fix it. Seriously 200k on these 4.3’s is literally just the break in lol. Assuming some youngster ain’t had it thrashing it everyday lol. If maintained with just ur basic oil changes u will get 400k-600k before u lose significant compression. I had a 95 blazer and it had 375k and it was lucky if I changed the oil once a year!! Traded it for safari van for family and it still ran like a top. Didn’t knock, tick, or smoke.

 

I've tore several of these engines down with mileage between 150k-230k. None showed any sign of ring groove in the cylinders and the hone marks were still visible.

I have 270k on one that needed a crank kit put in it at 180k due to the intake gasket leaking coolant in to the crankcase and wiping out the crank and bearings. I also installed a new timing chain, oil pump, crank seals, and head gaskets. I just left the pistons in the block and started from there. Oil usage is very minimal.

I have another Blazer currently that I bought cheap with a blown intake gasket. I removed that engine because it also had a rattling noise. (later found that the starter gear was bouncing around and hitting the flex plate). I plan on just replacing crank bearings and seals, oil pump, timing chain, and head gaskets on it also.

 

BTW

I'm just building one for my 1994.

https://blazerforum.com/forum/builds...ueprint-92047/