integrity640

Hey Guys,

Need some opinions....

2006 Silverado 5.3
L33 5.3 HO motor "B"
203k miles
Original Owner
Always kept up on maintanence and ran royal purple through it


Issue Ive been having:

1.) About 4 months ago for a 3 week period on startup id have a cloud of white sweet smelling smoke shoot out the exhaust, which led me to believe Ive got an internal coolant leak. At the same time, my reservoir also started going low.

I ran UV dye through the coolant system and have found no trace of it upon multiple uv light inspections, including around the water pump and radiator.

2.)This led me to believe I have the doomed Castech heads, however after many hours of research people where saying that the 799 heads weren't affected, even though the 06' L33 was listed as a potential victim on the GM service bulletin. After speaking to a friend who has buddies that work at Nissan/GMC, they both said it'd be worth replacing the engine with a low mileage junkyard motor. I'd like to get another 4 years of life (100k miles) out of this truck since I'm still in college and the truck body and interior or very well taken care of.

If i choose the route of head replacement, would it be worth/ safe for a daily driver to throw the extra money into a ported set of 799 heads from a reputable company such as Texas Speed, advanced induction, etc? Or just stay with a OEM set of 799 heads?


If you where in the this situation, what would you do? Id be doing the work myself along with the help of some very experienced guys, but would a head job just be putting a band aid on the gaping wound? Or is an engine swap truly the way to go?

Also the truck burns a quart of oil every 1200 miles or so.

Thank you all for the info, Ive researched heavily into this problem, but not found the exact answers Im looking for.

Also without pulling the heads off would a leak down test be a sure fire way to diagnose if the heads are cracked or not? Is it possible is could be an intake manifold gasket gone bad or a possible head gasket gone bad?

Thanks again,
Ben

PS keep in mind I'm in college and don't have a bottomless bank account, the end goal is to get another 100k miles out if the truck at least till I'm done with school

RockinWs6

At that mileage I'd toss a leak sealer in it and call it a day. Could be cracked head or head gasket, intake has no coolant flowing through it. Easy way to find the leaking cylinder is to let it sit over night then pull all the plugs and crank it over to see which cylinder the coolant is getting into.

Hamrdown

iTrader: (25)

I'd swap a different set of heads on first. How bad would it suck to spend almost a grand on head porting to find out it doesn't fix your problem. If it does, then porting the heads is a great bang for the buck in a 5.3. All it would cost you is another set of gaskets & head bolts.

Darth_V8r

iTrader: (4)

If I was in your shoes, I would pull the heads and check the heads with dye penetrant to look for cracks. If the penetrant shows no cracks, install new head gaskets, use new bolts, call it a day. if the heads are cracked, you're only out a kit of dye penetrant. a used junkyard motor might be cheaper than a new set of heads. I've seen weird stuff like that before. Depends on the parts market where you live.

I've picked up cheap 243 heads, because they were on a truck motor, and the owner didn't know what he had. Got the motor cheaper than the heads from others.

integrity640

Darth_V8r, Hamrdown, RockinWs6,

Thank you for the input guys, a little update. I took my truck in today to have the exhaust manifold bolts pulled as the rear 2 on each side had snapped off, I had a new piece of exhaust pipe welded in behind the driver side cat, the tech said there was atleast 50lbs of pressure pulling from the exhaust side of where the manifold and cat meet, which would explain the broken bolt heads amongst other factors.

Anyways the driver rear bolt broke off flush in the head, its in a super tight spot so the guy couldn't reach it with a left hand drill bit even on a small angle drill. All new bolts, minus the one and gaskets where thrown onto it. While working on it the coolant system was pressure tested, no external leaks, definitely an internal leak.

In the long run ill need to pull the heads off to gain access to the bolt and have it drilled out, for now is there any test I can do to distinguish a possible cracked head vs intake manifold gaskets vs head gasket as the culprit?

RockinWs6 I know you said theres no coolant flowing in through the intake manifold which I agree with, a leaking intake gasket wouldn't cause coolant loss though? Do i theoretically have it narrowed down to a head or head gasket? I just have a hard time believing after 200k miles and 9 years its the head, id assume it'd be the gasket to go first since a castech issue(if it is a casttech) would've shown up a 100k miles ago.

Thanks again for the input,
Ben

gagliano7

A leaking intake gasket wouldn't cause coolant loss it would just give you a vacuum leaK.

dr_whigham

iTrader: (49)

Id be more inclined to think head gasket. If you DO send the heads out to be ported, they'd surely test them at that time to make certain.

integrity640

So being that its been narrowed down to a head gasket or cracked head, I need to pull the heads to A) inspect for cracks/gasket B) to extract the bad bolt

Im considering going through Advanced Induction and getting either of these 2 options....

http://www.advancedinduction.com/LSX...cGMLS2Head.php


or


http://www.advancedinduction.com/LSX...43GMPRHead.php


Both seem reasonably priced options, I sent them an email, just waiting to hear back. Aside from a ~$250 price difference, any reason to or not too go with either or choose one over the other?

Fry_

Unless you plan additional mods and plan to build up the truck and keep it for a long time save your money and just leave the heads stock. Also with that many miles I'd consider changing the lifters while the heads are off just for a little piece of mind.

alamantia

iTrader: (10)

here is your answer.

http://ww2.justanswer.com/uploads/Bl...t_loss_5.3.pdf

RonSSNova

iTrader: (3)

L33 will have 243 or 799 heads.

integrity640

Fry_ Ive got an Outlaw intake, exhaust and Westers Tune on the truck, I figure it might be worth it for a few extra ponies on the hood.

Alamantia I got your message, Im aware of the GM service bulletin, thank you for the heads up on it though. I haven't heard of anyone having issues with 799 heads, just the 706? from Castech.

Darth_V8r

iTrader: (4)

True, it is normally castech 706's from 03-06. At 200,000 miles, if I'm pulling heads, I'm doing something to verify no cracks beofre reinstalling. Cheap, effective insurance. And you'll know for a fact that the heads weren't the issue. I'd be 85% sure it was the head gasket, but $50 is worth being 100% sure.