LM7 help please
LM7 help please I have a stock lm7 i believe in my 2004 chevy siverado 1500 and it has recently started to burn oil and i think a little bit of coolant. Also started to clack real loud on a cold start only for about 15 seconds, then it goes away. No idea if the noise is related to the loosing fluids but maybe someone on here knows. Also, i have been told i might have a bad head gasket, a leaking valve seal, and maybe a leaking hydro lifter. Truck has 90xxx miles on it and runs perfect. Minus the loosing fluids of course. Just throwing it out there to see if anyone could point me in the right direction on what i should check and or do. Also, an idea i have had, a friend of mine has a 5.3 engine out of a 2006 truck with 30xxx, any idea if the engine will directly bolt in and plug in, or is there some mods i might have to do??
Thanks
Zach
Thanks
Zach
Oil burning is adownside of the LSx family. They all do it to some degree. Check your PCV valve for proper operation. GM attempted to address the issue with later engines by swapping the PCV valve for a "fixed orifice tube" meaning a plug in the PCV hole, with a tiny holes drilled into it. If you have that, then there is nothing that can be done for oil consumption, besides it shouldnt be more than 1 qt per change. The pan capacity is greater than older engines for this very reason
On to the suspected head gasket/coolant leak. Do a compression/leak down test first. Next, do a pressure test of the cooling system. Hopefully its just a worn hose
Finally, the 06 LM7 will replace your 04 LM7 directly
Be sure they're both iron block, have black crank sensors and cyl heads are either 862 or 706
On to the suspected head gasket/coolant leak. Do a compression/leak down test first. Next, do a pressure test of the cooling system. Hopefully its just a worn hose
Finally, the 06 LM7 will replace your 04 LM7 directly
Be sure they're both iron block, have black crank sensors and cyl heads are either 862 or 706
To investigate the losing coolant a little more do some searching on "castec" they were a vendor that made heads for GM and they made some of the 706 heads poorly and they crack, weep coolant and it can cause things like cold start noise.
Coolant level on my truck has been a little erratic but passed a combustion gas test, trying to figure out what I want to do about it???? Not decided on swapping heads or swapping in a 6.0l.
Coolant level on my truck has been a little erratic but passed a combustion gas test, trying to figure out what I want to do about it???? Not decided on swapping heads or swapping in a 6.0l.
Cracked heads will show up in a leak down test. Even the weak casting heads will not crack unless the engine is severely overheated
For your coolant issue, do the pressure test. You can rent the tool from advance auto. Pump it up to 8-10psi and leave it for an hour. If it leaked down more than 1psi, you have a leak somewhere. Get some dye
For your coolant issue, do the pressure test. You can rent the tool from advance auto. Pump it up to 8-10psi and leave it for an hour. If it leaked down more than 1psi, you have a leak somewhere. Get some dye
Also the clack on cold start is a common occurance with the LS based gen3 engines in general . It is piston slap that is caused by pistons that have fairly short skirts and when cold there is a little more than desired clearance between piston and cyl bore . Generally there is'nt anything to worry about , and I suspect You either have some coolant leaking into a cyl via a cracked head or via failed head gasket . That is if the clack just started in conjunction with the fluid loss issues . Good luck
