Replacing rod/main bearings without pulling motor

[Yellow Cheyenne]

Is it possible to replace the rod and main bearings in a 96 Vortec motor without pulling the motor? I have a 96 4x4 suburban that if I remove the front differential I have pretty good access to removing the oil pan. I don't think that replacing the rod bearings will be too difficult, but don't know how hard (or if even possible) it would be to replace the main bearings without at least pulling the transmission back to allow dropping the crank out. Can the block half of the bearing be "rolled" in without dropping the crank? I just bought this thing and it was getting antifreeze in the oil. Replaced the intake manifold gaskets and that problem is fixed. It runs good and carries decent oil pressure, but I have heard that antifreeze in the oil is hard on bearings and thought if I could replace the bearings without too much hassle, that it might be good insurance against future bearing failure.

TIA,

Randy

(I posted in 88-98 board but know this one gets more readership)

[oldsub86]

Wouldn't it just be easier to pull the motor out? Certainly more likely to do a good job of it if you have it out where you can get at everything and check clearances and use the torque wrench without stuff in the way. If you don't really dismantle it you should be able to pull the engine and fix it and drop it back in pretty quickly.

[cdowns]

to replace the bearings the crank should be pulled out and measured/machined for proper clearance it's not a job easily done with the engine in the car/truck

[beautimus]

just my 2 cents, but it seems to me that the good oil presure is a pretty reliable indicator of bearing condition. personally i would let the motor cool off over night and start the engine when its cold, if it doesn't rattle, and has good oil pressure that comes up pretty quickly, i would just drive it.
in other words, i think you fixed the problem , before any real damage was done.
tony

[stllookn]

I've tried to replace the mains and rods without pulling the engine and it is a real hassle. The oil dripping on your head and the mess is a real pain. Getting the mains out is nearly impossible without pulling the engine and crank...let alone getting them torqued from under there. I agree with Tony, if you still have good oil pressure you probably don't have a problem at all! Change the oil again and go for it!

[72C203503ONTHETREE]

I replaced the rod bearings in my 76 4x4 but could have done the mains also. Its not that bad to do, theres special tools that you can use but a flat flexiple tool made out of plastic or even soft metal will work. I have replaced main bearings without removing the engine in a 82 Landcruiser FJ60 with a six cylinder. The bearings werent really bad but I had the pan off for something else and did all the bearings while I had it off for good insurance. The way to take car of the oil dripping problem is to let the engine sit over night with the drain plug out and then spray carb or brake cleaner up into the engine, it stops 99% of the oil drippings plus cleans out the engine.

[Longhorn Man]

Just chainge your oil sooner than you are suposed to for the next few times...like maybe every 1000 miles for the next 3000. This will help get rid of the coolant that you don't see on your dip stick.

[Yellow Cheyenne]

I've put about 500 miles on it and changed the oil 3 times during that time. I too thought I would just call it good and go on until a couple of days ago. A friend had bought a 99 burb that ran good until recently. It developed a rod knock so the engine was disassembled to find the crank had significant wear on one rod and all other bearing surfaces were marginal at best. He had driven it about 20,000 miles in the last year. When it was disassembled, the intake manifold showed signs that the intake manifold gaskets had been changed. The theory is that it had also gotten antifreeze in the oil and that the intake gasket was the only repair done to it. I bought mine knowing it had the problem, but don't have any idea how long it was run like that. Judging by the general upkeep on the rest of the vehicle, I am afraid it was run like that for more than just a few miles. If it were just me driving it, I wouldn't worry about it too much, but this is now my wife's main transportation and she occasionally goes on 300 mile trips with it, hauling our to kids so I don't want it to strand them somewhere. Was just wondering if it was possible to do bearings from underneath and spend 4-5 hours as opposed to pulling the motor and using a weekend to replace the bearings.

Randy

[walker]

Maybe you should pull the pan, check one or two rod and main bearings with plastigauge and see. If you have loose bearings then I would pull the motor and do a crank job.
If I were going to keep it for a long time I would consider a valve job while it was apart for the bearings. Oh, and a performance cam too...

[jimfulco]

A friend of mine replaced the crank bearings on his '93 4x4 Suburban with the engine in a couple of years ago, no problem. I don't think he messed with the transmission at all.