Replacing 2001 LQ4

[jmckelvy]

Hi All. New member here.

I have a 2001 Chevy 2500HD, AT, 4X4. I am the original owner of the truck with 76 k miles. The engine runs great except for a tapping noise which I think is the dreaded piston slap. The noise is most noticeable when cold but can also be heard after warmup particlarly under load between 2000 and 3000 rpms.

The tapping noise is driving me nuts so I am considering my options. The one I am leaning to is a late model engine from a salvage yard. Lots of these engines are available for less than $2000. However after reading some of the threads on this forum I have some questions.

Crank length---Is this going to be a problem? If so what is the workaround?

Displacement on Demand---What year was this first offered? Should I avoid any engine of this type?

Throttle body----I have the mechanical cable style. If I get an engine with the electronic throttle can I just put my original TB on?

Any other issues I should be aware of?

Thanks

Jim

[rutroe]

Welcome to the site! You should be able to find the answers you're looking for here.

[GasGuzzler]

The 07 5.3's have active fuel management. Not sure when all the engines got it. You need to avoid these.

The throttle body swaps over as long as your new engine has the "old style" 99-06 intake manifold from a full size truck.

[6.0Silvy]

The AFM is actually part of the tune, not so much the motor itself. I think you would be ok to run that motor if you got the right crankshaft for it. Which I think yours should be ok.

[2500hdee]

I was able to eliminate my loud piston slap (in my '01 2500HD 6.0) using this procedure from a Vette mechanic from a GM TSB that I can no longer find. Mine was loud and after this procedure-was gone. I bought two cans of GM's top end cleaner Part #88861802-removed all the spark plugs-poured the cleaner into all 8 cylinders-let it sit 6-12hrs, put rags over the plug holes and turned the engine over for 20 seconds-those rags got covered in nasty dissolved carbon-replaced the plugs with NGK TR55's-changed the oil and filter. No more piston slap-it has now come back but is almost impossible to hear at 177K. I believe the original TSB called for 20min of idling after replacing the plugs but I wasn't comfortable with the engine idling with the oil possibly diluted so I skipped it. Worked great for me; I'll try again to find the write and post it up if possible

[GasGuzzler]

I've been saying that for a while but people want to have piston noise so it stays the same...