Hi all
Going to pick up a LQ4/4l65e out of 2007 hummer. Engine will be sitting on pallet.
I've done leakdowns before on other trucks - but have been in truck and cant remember something ....

Does it matter when rotating the engine if the transmission is in Park. I dont think so. Or does it have to be in neutral.

Anything else to check whilst Im there. Going to gran the TAC and harness and peal if they have it - but not sure they do so will have to source aftermarket.
I'd like to drop the pan and check the rod bearings ..... but dont think thats going to happen.

thanks all

 

Hi Ky, remove the engine oil filter, cut it open, post a picture of the element.

PARK effects the Drive Shaft.

NOT GOOD to Leak a "cold" engine, bad read.

Lance

 

Not sure why cold is bad except rings not fully seated.
only had 8-12% across all 8

 

Oil looked clean on stick

I'll pull the pan when I can get off pallet and check for metal

I'll try cutting the oil filter also.

But I basically own it now

 

Because a warmed up engine will have oil on the rings that makes them seal. Also things expand when they get warm and that helps too.

Sometimes a cold engine/engine that's been sitting will test low.

 

Understand that -as mentioned above.
but with 8-12% leakdown on cold - seems like its fine.

Anyway - engines on the back of truck in driveway - got to go figure a way to get it out (gravel/shel drive) ...... then get the trans seperated for a 4WD=>2WD conversion and clean it all up

 

The reason you check it hot is because when the engine is in use it will be hot. The block shape and size change as the engine gets up to temp. Bore and piston sizes change, heads move around on the block etc.

 

8-12% cold leak down sounds okay. Have you ran a compression test on the engine? Both of these tests should be performed on a cold and warmed up engine to check the overall health of the cylinders and heads.

 

No compression test - no way to get warm - the engine/trans was sitting in on pallet.

Think 8-12% leakdown on cold engine with 69k miles ..... should be ok.
Wasnt wrecked either. Came from a shop that specializes in hummer gas =>diesel conversion.