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i have an 07 avalanche with an LC9
i want to do a straight stick rebuild.
im very mechanically inclined. Ive rebuilt a standard transmission. Never a motor yet. And im a little intimidated.
i keep looking for a block to start with. But maybe im better off pulling mine and starting there.
Id like to do a DoD delete. And literally keep everything stock.
the motor runs great now, just leaks oil pretty well and burns it. I’m adding way too much between changes.
So, to start, I assume I’d be best tearing it all down. are there any parts that you’d reuse?
Or any starting points would help. I feel a little lost and a bit stressed about it
If all you want to do is cure the leaks and oil burning, you can tear it down, clean it, put new piston rings and bearings in it, do the DOD delete, and reassemble with all new gaskets. As long as you're able to follow correct torque sequences and understand that you can't reuse some of the bolts in the engine ( head bolts ), you should be able to accomplish it. It's just time consuming. I'm building an engine right now, and there's a lot of little things that go into it.
Oil burning is not usually a short block problem in these motors, unless maintenance has been SEVERELY neglected. More likely it's the heads. Specifically, valve guide seals. They're fairly cheeeeep. "Rent" a spring compressor and swap em out.
No sense in spending $3000 fixing a $100 problem.
Take the truck to the quarter car wash and clean up the engine thoroughly so you can see the whole thing. Remove the inner fender liners so you can clean it from the sides. If it has skid plates, take them off, and remove the plastic piece below the radiator. Blast it from all sides including from underneath. Find the leaks. Most likely source is the oil cooler line bypass plate. Kind of right above the oil filter; 2 small bolts. DO NOT try to tighten them!!!! They are only 6mm, which has a rather fine thread, and they only go into aluminum; therefore the holes strip VERY easily. In fact, if that's where it's leeeeeeking from, that might be why they leak in the first place: it started leeeeking there, and some PO decided to try to "fix" it by tightening them, and now they're stripped. If so, you might need a right-angle drill, to Heli-Coil them.
You will never drain 6 qts out of an LS at oil change time, having put 6 qts in initially. They use a half quart every 3k miles from brand new. Gen3 or Gen4…doesn’t matter. It’s not an internal issue, it’s the crappy PCV setup. Really gums up the intake after time. It’s awful. How much oil are you using between oil changes? You might simply need to fix an oil weep issue, instead of a rebuild. These engines go 300k-500k miles easy with regular maintenance.
Yeah I forgot about that; the oil burning might be entirely due to the PCV system. Although, you should have the newer style valve covers, which are MUCH better than some of the early ones, that the baffles were total crap. But, new valve covers such as Dorman, will fix it, if that's where it's coming from.
But like Che70velle said, these motors will go RIDICULOUS miles without needing a "rebuild", given even the most basic maintenance. You almost have to DELIBERATELY TRY to kill them quicker than that.
I'll stand by what I said. These engines are old, and the gaskets leak. My '06 LQ4 is leaking from the rear main seal and was leaking from the valley cover until I did a knock sensor job. And yes, the valve seals on mine are shot and that's part of the oil burning issue. Maybe the re-ring job is overkill, but I have another LQ4 that had glazed cylinder walls and would definitely have needed a clean up hone and new rings at minimum. The PCV system sucks too. There's a lot of things that can be upgraded and/or fixed that the OP can try before going all the way to a rebuild, but if he goes as far as to pull the engine for new gaskets and DOD delete, it's not much more work to do a ball hone and new rings. Just my opinion.
It’s pretty common for the DOD equipped engines to fail around 200k miles from collapsed lifters. It happened to my 09 avalanche @205k miles. If ur close to 200k replace the lifters and do a DOD delete. If not, why throw money away on a stock rebuild that unlikely needs one? Find the leak and fix only.
Oil burning is not usually a short block problem in these motors, unless maintenance has been SEVERELY neglected. More likely it's the heads. Specifically, valve guide seals. They're fairly cheeeeep. "Rent" a spring compressor and swap em out.
No sense in spending $3000 fixing a $100 problem.
Take the truck to the quarter car wash and clean up the engine thoroughly so you can see the whole thing. Remove the inner fender liners so you can clean it from the sides. If it has skid plates, take them off, and remove the plastic piece below the radiator. Blast it from all sides including from underneath. Find the leaks. Most likely source is the oil cooler line bypass plate. Kind of right above the oil filter; 2 small bolts. DO NOT try to tighten them!!!! They are only 6mm, which has a rather fine thread, and they only go into aluminum; therefore the holes strip VERY easily. In fact, if that's where it's leeeeeeking from, that might be why they leak in the first place: it started leeeeking there, and some PO decided to try to "fix" it by tightening them, and now they're stripped. If so, you might need a right-angle drill, to Heli-Coil them.
this for sure! I believe.
two lines coming from the front of the motor.
ill see if I can attach a picture.
im sure it needs a rear main seal as well.
i bought it with a dod bypass plug in. No lifter noise. 260k miles.
valve guides? Most likely.
maybe a whole pull and reseal is overkill. I just wanna make sure I do a complete job and save myself a headache later.
what can I do to fix the pcv system?
I’ve been told that the valve guides are bad since it can be a puff at start up. Not always. Just after long drives. 90-100 miles.
as far as how much I’m going through? Man… I probably add a quart every 3 weeks.
i need to track my milage better.
t
To be honest. I’ve only had this truck for 6 months.
The lines in the pic are the trans fluid cooler ones.
Not motor oil. Wrong side of the motor besides. Also you haven't taken off the plastic air shield thing like you've been told you need to do before car-washing the motor at the quarter car wash.
After you go to the quarter car wash with acoupla cans of "engine degreaser" (diesel fuel in a spray can) and clean your motor up to where you can actually SEE the metal, and the nice fresh new clean oil dripping in plain sight, instead of the funk of 10,000 years, look right above the oil filter for this little thing. https://www.gmpartscorp.com/p/Cadill.../12577903.html That's the part that has the 2 bolt holes that always strip when Stimpy tightens up the bolts to stop the leeeeeeks.
The 2nd pic looks OK; pretty normal for the most part. Looks like you haven't been to the quarter car wash yet, meaning, not taking the advice you've been given. If you're not going to follow instructions, why bother asking? All I see is just a giant blibbet of filth, dust, etc.; totally uninformative. Not sure what you wanted us to see? (beyond that you haven't done what you've been told you need to do)
Wouldn't hurt also, to tell us which head castings you have. Look at the pass side head, front outer corner, immediately below the oil filler tube, and below the valve cover flange. There'll be a 3 digit number. Might be 243, 706, or some such. Tell us which number you have.
Any signs that the oil is turning into something sort of brown and opaque, maybe a bit chalky, not really a very good lubricant anymore?
Following along as i have aquired a 09 LC9 with 250k and a collapsed #7 lifter. Cross hatch in all cylinders still. Cam bearings dont look great. So i plan on BTR dod delete kit with truck norris cam. Along with a
re-ring and re-bearing and have the 243 heads gone through with about .030 shaved off. Nothing special. Would love to hear bearing and ring recommendations for quality ones.
I am way behind on this and I’m sorry….
i got an opportunity for a better job. Had to move. And kinda put a lot of this on the back burner 🙃 super exciting things… anywho…..
im on mobile. Cant remember if i said i had to change the fuel pump? I changed the fuel pump…. Had to fix some lines. Works great.
earlier this week I had a misfire come up….
changed all the spark plugs. Did a compression test and all cylinders checked out.
did the manifold water test…. And had a stumble and steam out the exhaust…
ok pulled the manifold today, new gaskets arriving tomorrow….
new valve cover gaskets on Friday.
still gotta address the pcv system. Will reread comments, because got a bit of oil
in the manifold.
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New! Looking for help on a rebuild 
