the 6.0 im swapping into my truck has low compression on the 3/5 cylinders, all the other cylinders have good compression. but when its running it skips an thinks it running lean, sounds almost like it has a cam lol.im running it now with a 04 5.3 tune, im gona have them reflash it an put a stock 6.0 tune on it then tweak it. would it runnin on the 5.3 tune make it do this?. i bought it from a junkyard they said it was all good, get to swaping it an pull the plugs to put in new 1s, an those two cylinders had rust at the top. so i think its nothin major get it all put together an now it sounds like a 90s diesel its so loud. idk wtf it is doin , ive got all my cash in this swap, havin a shop do it for me, all this is what there tellin me over the phone, an i kno im not describing it tht great but any thought or suggestions, plz an ty.

 

Where do you live? My buddy bought a motor that was a flood damage vehicle, that he didn't know about till after he put it in! I've seen a bunch of engines @ the junk yard un covered with parts missing off them that would cause ur problem.. But it could just have a blow head gasket.

 

Ga. Hope it is. Trying to keep my mechanic out of my pocket tearing the motor down. Ne1 else?

 

Low compression on two cylinders side by side is usually signs of a blown head gasket, it's quite possible that's the problem...

 

Would it hurt nethin if i drove it a 100 miles like tht? I kno it can't b tuned properly like tht, but is it decent to drive?

 

If it's leaking coolant it could wash the cylinders down and get coolant in the crank case, or overheat...either way could lead to catastrophic failure. You'd really be rolling the dice if that's your problem

 

Its not leaking tht can b seen. Just rattling an running like **** with low compression on those two cylinders.

 

Thoughts?

 

Theirs no way of knowing how long it's been like that! So I pull it & get another one!

 

Well i already have more then i planned tied up in it. An idk if the junkyard will help me out, already paying extra labor.