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04 Pre-Buy

1994ch

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I have a friend who is looking at an 04 (pretty sure he said it was an LLY). It has a little over 200,000 on it, no record of the head gaskets being replaced yet. He heard that these engines are known for having the head gasket go about this mileage, and was wondering if he should plan on replacing it ahead of time as preventative maintenance or not. My leaning is "if it ain't broke don't fix it" but I don't know much about these engines and if there tends to be a lot of collateral damage when they go out or not.

Also any other important things to look at / consider?

Thanks
 

Will L.

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He really needs to decide how long he wants it to last.

wether it is better to have it fail at an unknown point but save money up front, of yank and rebuild now so it is good for the next 200,000 miles.

You can always find examples of engines that die way before they should, and ones that go a bazillion trips around the universe. GM said it was “tested to survive upwards of 200,000 miles...” doc # 2021833.
This is the same mile they said in the advertising for the 6.2.

Yes the dmax will survive longer than a 6.2. How much depends on that individual engine, it’s use, etc. In the end that Dmax should be considered NOT RELIABLE legally. If it were in an ambulance, police vehicle, etc people would flip their lid and win a lawsuit if it had issues resulting in problems as opposed to one with say 75,000 miles on it.

So it is a personal question- how important is it to be reliable?
How much money can he/she spend before it goes into use vs drive it until the day the tow truck picks it up and unplanned down time. It is always less expensive to rebuild before failure related breakdown occurs.

When looking at any used vehicle imagine if the person just had the engine rebuilt exactly the way he/she would choose but the purchase price is higher by that amount.
 

WarWagon

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A 2004 may not be an LLY. Your friend needs to be dammed sure is isn't. Because if it is an LLY RUN AWAY!

You couldn't give me an LLY as that is a prime example of a GM cooling system that couldn't cash the power check the engine wrote. Oh Wait: it has a number of problems GM never admitted too like a 4PSI restriction before the turbo on a bad mouthpiece design, a blind system that will run the variable turbo past it's choke point blasting the radiator with 500 degree air out of the intercooler to get X boost... Threads on Quack cures to fix the damn LLY overheating problems get locked.

It's a problem engine and you have been warned. Pick another year: ANY other year including a 6.5TD that can kick an LLY's ASS when towing through Death Valley because the cooling problems on a 6.5TD can be solved. Been there and wished I would have used the 6.5 not the LLY for that trip. There is even a video that won a Lemon Law Lawsuit showing a early 1990's Cummins 5.9 towing a 5er outrunning an LLY as the LLY overheated again and lost power.

And anyone who wonders WHY I drive Cummins in a Dodge wrapper the LLY is a big reason...
 
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MrMarty51

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Glad this subject has come up.
Right along side where I been working, there is a Duramax K2500 setting there, year unknown, My boss has contact info for the person that owns it. I am thinking of having Him contact the owner and see what the specifics are on the truck, year, mileage etc, and, I have been thinking about buying it. all I know is the truck is darkish grey, has 2500 on the front fender and Duramax under that.
Also, towards the front left side, on the cement driveway, there is a puddle of blackish looking goo. The body has seen some abuse but it is rust free.
Guess when I find out more about it, and, if the bank will finance the truck, I`ll start a thread on it. LOL
 

WarWagon

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LLY engines have an EGR valve, prior years do not. Look for the EGR equipment on the passinger side of the engine. I recall it's also on the emissions sticker: both LLY and EGR.
 

THEFERMANATOR

FRANKENBURBAN
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LLY engines have an EGR valve, prior years do not. Look for the EGR equipment on the passinger side of the engine. I recall it's also on the emissions sticker: both LLY and EGR.
Incorrect, there are thousands of LB7's with EGR's. All Cali emissions, northeast emissions, and a good percentage of 04 LB7's all came with EGR. LB7's were the only Duramax's With injectors under the valve cover. LLY+ all had them external. Check the 8th vin digit, 1=lb7, and 2=lly.

I'm in the minority, but I like LB7's. Spend the money on some SAC injectors and enjoy them. Yes some LLY's overheated, but not all of them did, and they were by no means to be avoided. I've personally fixxed 2 overheaters by replacing the intakes with high flow units(full lbz on one, aftermarket on the other), sealing the airboxxes to underhood air, open up the fender to flow the required air, added an intake behind the headlight, egr blocker plate, exhaust, and a mild tune. One of them is on 34's and routinely runs at 30-32k gcvw through the mountains. The other was a hot shot rig running at 26k everyday. Oil cooling is also recommended as lly's run the oil hot.

They ALL have there pro's and cons, but none of them would scare me away until you get to 2011 with the lml and the wonderful cp4.
 

MrMarty51

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Incorrect, there are thousands of LB7's with EGR's. All Cali emissions, northeast emissions, and a good percentage of 04 LB7's all came with EGR. LB7's were the only Duramax's With injectors under the valve cover. LLY+ all had them external. Check the 8th vin digit, 1=lb7, and 2=lly.

I'm in the minority, but I like LB7's. Spend the money on some SAC injectors and enjoy them. Yes some LLY's overheated, but not all of them did, and they were by no means to be avoided. I've personally fixxed 2 overheaters by replacing the intakes with high flow units(full lbz on one, aftermarket on the other), sealing the airboxxes to underhood air, open up the fender to flow the required air, added an intake behind the headlight, egr blocker plate, exhaust, and a mild tune. One of them is on 34's and routinely runs at 30-32k gcvw through the mountains. The other was a hot shot rig running at 26k everyday. Oil cooling is also recommended as lly's run the oil hot.

They ALL have there pro's and cons, but none of them would scare me away until you get to 2011 with the lml and the wonderful cp4.
Well, with this new information, I guess I will purchase that truck no matter what year it is, although, I do know it is not a 2011. it does have some smaller body damage and peering through the window its a bit grungy but I`m sure it can all be cleaned up and straightened to make for a rig to seel and possibly make a phew bucks on. LOL
Okay, end of My Hijack. LOL
 

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FRANKENBURBAN
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Many shy away from LB7's because of the injector which makes no sense because they all can have issues with injectors. Having done injectors in both, I actually preferred doing my LB7. I didn't have all the crap stuck down around the injectors and hold down bolts that get half rusted through. But this is just me. And headgasket issues are an issue on most all of these older trucks because of age, milage, and heat cycles on them. It has nothing to do with dexcool like I've seen so many try to blame it on.
 
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