1999 jimmy rear engine knocking

My 99 jimmy with 230 klms/170 mi. started knocking and it sounds like it’s coming from the top rear engine area, had it to several mechanics that say its a ristpin, or collasped lifter. I have the lifters out now and they all look good , should I just replace them or can I test them some way to see if that was the problem. I’m stuck not knowing my next step.

3 thoughts on “1999 jimmy rear engine knocking”

  1. If you had a collapsed lifter, one of them would look different in which the center plunger would be lower than the others hence being Collapsed.

    I would not bother replacing them unless one of them looks this way.

    Your next step would be to tear down the rest of the engine and inspect the rod and crank bearings and wrist pins.

  2. on some of the lifters the cup end appears to be (on some) up to the retaining clip, and some are about 1/8 in lower, does this mean that they (the lifters with the lower cup) are bad? I have made the choice to pull the engine as it remains and replace it with a good low mileage engine, and later tear down the existing 4.3 to determine the real problem. It possibly might be worth fixing later. Thanks for your comments!

  3. 1) on some of the lifters the cup end appears to be (on some) up to the retaining clip, and some are about 1/8 in lower, does this mean that they (the lifters with the lower cup) are bad?

    1) YES!

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