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Discussion Starter · #1 ·
Hey guys just wondering if any of you have had troubles with the GM 4.8 motor. Dad has one in his '04 sierra and awile back started noticing we were putting more antifreeze in more often then ever until eventually we were putting a pint in every few days. turns out BOTH heads were cracked. decided were just replacing the whole motor. Apperantly this is a common problem with 4.8s and 5.3s. Just wondering if any of you guys have had this problem.
 

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Not yet, got about 120kmi on my silverado. Still runs great, but she eats about a quart of oil in 5kmi, but thats about it. First Ive heard of these engines having cracked head issues. I though all the cracked head issues were elimiated when the vortec motors came out?
 

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skiwhizlover said:
Apperantly this is a common problem with 4.8s and 5.3s. Just wondering if any of you guys have had this problem.
Just turned 130,000 miles on my 02 Silverado with the 5.3 and not a single issue. Doesn't use a drop of coolant, and maybe a little oil come every oil change, but that is to be expected. Don't think I've ever heard of an issue with the heads on either motor...
 

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5.3 no issues on my 04 Avalanche.
 

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My father has 150K on his 06 Silverado 4.8L with zero issues. My brother has 60K on his 06 with a 4.8L as well, but he only used a little oil. Again, first time I have ever heard about head problems.
 

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there is a known issue with these motors using coolant. only if the heads are manufactured by a company named Castech. then it will go through coolant and can lead to cracking. google it and you will find a big write up about it. my 02 5.3l uses very little and my dads 6.0l only uses some when we are towing and loading it up to the max. but otherwise i think they fixed it after 03. not 100% sure on that :p
 

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my 06 is going strong, it has a 5.3. but I have worked on alot of 4.8 and 5.3 for cracked heads, its a casting flaw. there is a TSB from GM about this problem.
 

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Discussion Starter · #8 ·
yea i forgot to mention the castech thing. If you pop your rocker cover off you will see there little C logo on the right side i think it was.I dont think all of them were made using the castech heads,i read somewhere that they were used from 01-06 but then again iv read of people taking the cover off and not having the castech logo, so i guess the only way to know is look for yourself. The motor had about 228,000 km on it. 2 new heads and a gasket kit was going to be 1500 bucks, when we could get a used 04' 4.8 (same engine hope it doesnt happen again) with just under 110,000km on it for 1600 bucks and has a 15 month warranty on it so thats what we did. New motor should be in middle of next week so il keep ya updated on things, il try and get acouple pics up to
 

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If you replaced the complete engine, you should have got a 5.3, they bolt right in and the computer is mass air, so It will run it!!
 

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Discussion Starter · #10 ·
polarisorbust said:
If you replaced the complete engine, you should have got a 5.3, they bolt right in and the computer is mass air, so It will run it!!
lol i said the same thing it would have really woken that truck up, trust me if it was my truck i wouldnt think twice about putting the 5.3 in. iv read somewhere that the 5.3 is just a stroked 4.8 by something like 9mm, is this true?
 

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i do love the 5.3l lots of power especially after a custom tune :) i have no problems with my motore, barely has any piston slap to :O. could not tell ya about the stroked part of it. all i know is the 5.3l is a copy of the 327 and the 6.0l is a copy of the 383. (from what i have been told anyways dont quote me on that) :p
 

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Im pretty sure the 4.8L, 5.3L, and 6.0L are all the same block, the larger 2 just being stroked versions.
 

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88400 said:
Im pretty sure the 4.8L, 5.3L, and 6.0L are all the same block, the larger 2 just being stroked versions.
true, but the 6.0 is only 20 more horsepower and not worth the extra gas, I have a chip, cold air intake and Flowmaster exhaust on my 5.3 and it runs pretty damn strong.
 

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comparing my dads 6.0l to my 5.3l i still t hink he will beat me and i am tuned. and towing if my truck was a 2500hd there is no way it would tow like his. if your towing and need a 2500 6.0l way to go :p
 

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the LS engine has nothing to do with the original small block design. Not even close to a 327 or 383 of the originals. dyno charts of a 5.3 is 307 hp, 6.0 is 323hp. the 6.0 does have more torque, but are designed to run in front of a 4L80 trans, not a 4L60, which is what comes in a 4.8 or 5.3.
 
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