Have a 1999 Chevy Blazer 4x4 which requires a new 4.3. Having acquired an example with 137k, what is the best way to make this unit last? I know they say 4.3s last forever but this one didn't due to issues the previous owner didn't mention. The Blazer has virtually no rust on the body so I have no interest in rushing the job as I want this motor to outlast the vehicle if possible. I have other vehicles and i don't have a time limit. What is the best way to do this? Is it worth putting in new bearings, rings, and resealing the motor? What else goes bad and should be replaced under the hood to help make this a reliable vehicle that lasts? The truck has 110k miles. Thanks also I know it is a gmc jimmy lol i have never called it a jimmy

 

Nice looking truck.

George

 

Honestly, in my experience good maintenance is by far the best thing you can do to make it last. Check and change your fluids on the recommended intervals, and when something needs replaced, use good quality parts. Trying to save money by using budget quality parts will almost always result in needing to replace those same parts in the near future.

 

Doing your own engine rebuilding depends on your skill level. Bearing clearances, cylinder honing and sizing, valve seats. etc. It only takes one assembly mistake. If you want a freshened up engine you may want to consider a long block from a reputable builder like Jegs, an outfit that one of our experienced members (Les) recommends.

Make sure that you have proper transmission cooling if you are towing.

Do the LIM gaskets if your keeping the existing engine

Do the door hinge bushings if failing to avoid welding repairs

As stated, stay on all the fluids so you don't trash rear wheel bearing, trannys, etc.

If your steering or suspension is getting loose, upgrade your replacement parts to Moog or equivalent. That's one area where AC Delco is not the best.

George

 

I want to second what George listed, i e., the lower intake manifold ( LIM) gaskets, door hinges, and extra cooling for the transmission.

For a transmission cooler, I installed a Hayden one that has worked really well for me. The installation is described in my build thread.

I would also suggest installing new oil cooler hoses and o-ring at the hose to block adapter.

If you have the engine out, and you see evidence of oil leaks at the timing chain civer or rear main seal, this would be the time to address them. Once the engine is in I've seen reports on the forum that is is crazy hard to service them.

Edit: If you have the engine our, it might also be a good time to get out any sludge in the cooling passage ways. The old version of Dexcool had issues with creating sludge.