My 05 silverado is becoming very thirsty. Burns a quart of oil every 2k miles and is burning coolant as fast a I put it in. It's either head gaskets or the infamous castech head issue. Either way I figured this is the perfect time to sneak a lq9 in there.so I picked up a 05 lq9 with 80k with all the accessories including computer for 1000.

Should I use the 6.0 computer? or run the 5.3 computer and get it tuned?

I'm going to perform a leakdown test on the engine once I get a leakdown tester. hopefully this will tell me what kind of condition the motor is in. If it's ok, I think I'm going to replace the gaskets and run it. Any objections to this? I'm not sure what kind of luck people have running junkyard motors.give me some advice!

From what I've read lq9s came backed by a 4l60e, so the flywheel should be ok? I'll know once I pull my 5.3 I suppose. Thanks for your help! Once I get a finger on the pulse of this motor she's going in.

 

I used the old 5.3 computer when I swapped a Lq9 in and got it tuned and it has no problems,only thing you have to prepare for is built tranny cause the lq9 tore my tranny and rear end up at the same time not sure if I was just unlucky or it was that powerful.

 

I was wondering if you ever found the problem with the L33? I have one in my 06 sierra and it is doing the same thing as yours. Just wondering what is causing it?? Any ideas?

 

80k you should be fine, I just had a LQ4 freshened up the engine builder said it probably had over 150k on it but still looked good didnt even need to bore it or any thing just cleaned up and new bearings and rings

as for the ECU i'd just get a tune on yours since your after the power any ways

these LS engines are awesome I love my 04 RCSB with the LQ4....

 

My l33 is definitely either the bad castings or head gasket. I was going to start my swap today and found 3 broken manifold bolts in the lq9. So hopefully soon

 

those are easy to get out if you have a mig welder and its aluminum heads, i've done this it works great!

How to extract a broken exhaust manifold bolt in 15 seconds lol - YouTube