92 4.3L 205k miles reseal or replace?

Discussion in 'GM Powertrain' started by 92WT, Jun 14, 2011.

  1. 92WT

    92WT New Member

    I have a 4.3L in my 92 K1500 4x4 5 speed that either needs to be majorly resealed or replaced. It has about 205k miles on it right now. It leaks a fair amount of oil from the intake and possibly the oil pan and crank seals, it also burns enough oil that I can smell it on occasion especially after first start up, which i believe to be mostly worn valve stem seals. Also when parked on an steeper incline like a boat landing in 1st gear the truck will actually roll down hill by turning the engine over. I don't know if that's normal with that heavy a truck even with a new engine, but I can't help but wonder if it just has generally low compression. I'm fairly confident a compression test would show all cylinders fairly close since it runs quite smooth and well, and I'm not sure the number itself would help me since they never seem to read what the book says even with different gauges. I can't figure out a good way to turn the engine over by hand to do a leak down test either, usually the bolt on the crank just turns in my past experiences with this sort of stuff. Oil pressure is about 30 psi driving or cold, and 20 psi warm.

    Maybe I'll just do the top end seals and hope that takes care of most of the leaks, I fear if i pull it out ill be tempted to pull it apart and itll get out of hand. If the engine is out, where do I stop replacing?
    The truck has a ton of stuff replaced on it already so it might be worth a rebuilt engine, not sure if I could get much better with a used one if I could find one.

    Also considered V8 swap but a complete donor vehicle of same year would cost too much, any any other way is a pain to get all the parts. Plus I rather like the gas mileage of the 4.3, and it has more than enough power for 90% of the things i do with it. It's just rather slow sometimes.

    As you can tell by my rambling I'm just going round and round confused.
  2. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    Just rebuild it with a rebuild kit/ and a good quality gasket kit if you want to take the time. Otherwise Replace the intake gaskets etc. and yes the motor will turn with a load on it the 4.3L is really not a big motor for holding back all that weight..

    If it were me i would simply do a set of gaskets and run it till it quits..

    and a V-8 swap just so you know is plug and play.. you only need a 350 w/TBI And the computer. Everything else bolts right up.. just to toss another wrench into your machine HAHA.
  3. TrailLeadr

    TrailLeadr Epic Member 5+ Years 1000 Posts

    Tough call, and I can totally relate to going overboard on it. I think you're on the right track with just doing the top end, and oil pan and see where that leaves you.
    With that many miles it would not be surprising if you had low compression.

    You can get a remote starter switch that's used to bump the engine if you don't fancy trying to turn it by the crank pulley.
  4. 92WT

    92WT New Member

    I'm actually aware of how easy it is to put in the same year 350 TBI but everything in the junkyards is trashed or stripped of parts, finding a good complete setup would take a donor vehicle that still runs well. Also with gas prices I just don't really need one.

    I work at an auto parts store so stuff is fairly cheap for me. Do these engines normally wear the cylinders enough to need all new pistons at this mileage? I'm not sure what I expect were I to take everything apart but I determined if I needed new pistons along with all the machine work it wasn't worth rebuilding this engine and I should just get a rebuilt one. If I just had to remove a small cylinder ridge and hone the cylinders for new piston rings that's not so bad. I am assuming that the cam doesn't wear much since its a roller cam, but I dunno bout the cam bearings. Not sure on the head what would need work, I hear heads usually need all new exhaust valves. Then maybe lap all the valves to get a good seal, check the valve guides and hope they aren't worn, put in new valve stem seals.

    I guess everything hinges on what parts actually wear on these. If I have to pull it to stop the oil leaks I won't be able to stop myself from trying a mild home rebuild on it.
  5. ToLate24

    ToLate24 New Member

    It depends on how hard you have ran the truck. From my experience rebuilding chevy engines, at 200k miles you can just hone the cylinders and you will be fine. I would have to agree with Murdog94...I would pull it, rebuild it, and run it till it dies. Like you said, you work at a parts store so you get a pretty good price on parts, go the distance it sounds like you have a reliable truck if the leaks were fixed.
  6. silveradotrailblazer

    silveradotrailblazer Epic Member 5+ Years ROTM Winner 5000 Posts

    You can get a new or remanufactured GM crate motor for not much more than what it cost to have it rebuilt yourself and you get a GM warranty. The biggest problem rebuilding the motor yourself is finding a GOOD machine shop.

    ---------- Post added at 09:15 AM ---------- Previous post was at 09:14 AM ----------

    Also the GM crate motors all have updated parts.

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