jimmys03
TYF Newbie
2003 Tahoe LT 160K orig trans
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Mileage Thread (00-06)
- Thread starter Donnie Yukonie
- Start date
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wow-really? is this common? this is where i wonder about my truck; 256k and runs great.
clandr1
Full Access Member
You didn't necessarily need to put in an entirely new motor if you caught it early on and replaced the heads. If you drove on it for a long time, then yes, it might have caused permanent internal damage. I wouldn't label the 5.3LS a POS since there are MANY here who have 200,000+ miles on their motors with no issues whatsoever.
It is fairly common on trucks that had Castech heads from 2002-2005, from what I've read here. I have heads with 706 stamped on them (which is indicative of Castech), but knock on wood I haven't had any issues with them in 144k miles.
http://www.gm-trucks.com/forums/topic/122232-trucks-going-in-to-see-if-i-have-castech-heads/
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True, but 243 heads are about $500 before install. So $1K later I have a 160K motor with reworked good heads. Is that a better investment or just find a good N (8th digit) LQ9 6.0 ** and be done with it? My used LQ9 + 4L65E cost me $2600 out the door installed. The shop also put in a new oil pump, rear main seal, new plugs & wires and gives a 24 mo/24K mile warranty. I would have been a fool to pass up that deal. I got tired of feeding oil and coolant 2x per week on my 5.3. The 6.0 hasn't used a drop of coolant and maybe 1/8" of oil over 3K miles. That could be attributed to PVC system. I am darn glad I did the swap. There is a small gas mileage penalty with the 6.0...more so as I now have to burn premium gas. According to the DIC, I was over 17 mpg tonight on a 25 mile freeway trip with the cruise control set around 65. MPG goes to heck quickly above 65.
The shop scrapped my old 5.3 motor because they did not feel comfortable selling it with a 24mo/24K warranty.
One of the best scenarios is to start with a flex fuel 5.3 and swap in a 6.0. The flex fuel injectors are 33 lb./hr. The 4.8/5.3/6.0 normal injectors are 25 lb/hr. So, use the whole intake manifold assembly off the flex fuel motor...and then get a Black Bear Tune.
I bought the Z71 used with just over 150K, so I didn't have much history. I am not saying all 5.3s are bad, just the one I had.
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clandr1
Full Access Member
I believe you have 862 heads, which from what I've read are good to go. You shouldn't have any issues, but it is always a good idea to check your oil dipstick and coolant level when you fill up just to be safe.
If the shop opted to scrap the motor, then it was probably too far gone to reliably rebuild. Look on the bright side - you had a very good reason to upgrade your motor just fall into your lap. Now you have a beast of an engine that will serve you well for a couple hundred thousand miles
Interesting reading about the Castech heads...never knew about this issue until it was brought up yesterday. Have an 04 Tahoe Z71 w/ 5.3 Z, flex fuel engine that has "862" casting # on corners of head. I bought it 18 months ago with 144k and it now has just over 180k.
I have noticed the coolant level seems to slowly drop with no apparent leaks....so I can't say "862" heads are good to go....yet. I've done the last few oil changes, no sign of sludge, but it can be hidden due to H2O burn off. No sign of sludge on dipstick. This Tahoe can make it between ~6000 mile oil changes without having to add oil. The best way to figure it out is pull valve cover and rockers, which I don't feel like doing. I read on another forum that an oil analysis will also show if coolant is in the oil. I might pop for that from Blackstone to avoid the disassembly.
I'm surprised to see jough getting that kind of mileage in a 6.0. I had an LQ4 in an '01 2500HD and no matter what it got 12-13mpg. Good truck, but the 6.0 has never been a mileage master. My current 5.3 Z averages high 15's in mixed driving and 16-17 on hwy. If I drove slower, average 70-75, it would probably improve.
I have noticed the coolant level seems to slowly drop with no apparent leaks....so I can't say "862" heads are good to go....yet. I've done the last few oil changes, no sign of sludge, but it can be hidden due to H2O burn off. No sign of sludge on dipstick. This Tahoe can make it between ~6000 mile oil changes without having to add oil. The best way to figure it out is pull valve cover and rockers, which I don't feel like doing. I read on another forum that an oil analysis will also show if coolant is in the oil. I might pop for that from Blackstone to avoid the disassembly.
I'm surprised to see jough getting that kind of mileage in a 6.0. I had an LQ4 in an '01 2500HD and no matter what it got 12-13mpg. Good truck, but the 6.0 has never been a mileage master. My current 5.3 Z averages high 15's in mixed driving and 16-17 on hwy. If I drove slower, average 70-75, it would probably improve.
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