I need some help with an LLY question

[socaltoolguy]

Can anybody give me some advice regarding the LLY diesel. When we were full timing we had a 2001 Duramax and had no problems with it but now I'm looking at a 2005 LLY with 189k on it. What should I know about it? What questions should I ask the seller? I really want to stick with GM products and this one is in our price range. Any help you folks can give me would be greatly appreciated. Take it easy on me. I'm old. Thanks for any help.

Ray

[rapidoxidationman]

When were the head gaskets replaced? Did they use bolts or studs to clamp things back together?
Has the transmission fluid been regularly drained and refilled with a fresh screw on filter can?
Did the engine coolant get changed at 150K?
Is the truck bed whole or has there been a 5th wheel mount bolted on? (speaks to the engine's working life)
Has the seller been religiously using a fuel additive on every tank of fuel? ULSD diesel is not very slippery...

I have well over 230K miles on mine and replaced the gaskets at about 160K. Used ARP studs. Pulls like a freight train.

[socaltoolguy]

Thanks so much for your input here. Those are all questions I would have forgotten to ask. As to the bed/hitch, the owner has a 5er hitch in it and has pulled a 32 ft trailer with it so that settles that. I'll inquire as to all the maintenance you mentioned though. Is it a known problem with the head gaskets? When I sold our 2001 it had only 75k on it and I didn't have any idea that it was going to need the head gaskets replaced. I kept waiting for the injectors to go bad but they didn't. The only time it ever gave me any trouble was my fault for stretching the fuel filter change a bit too long and it quit on my just outside of Benson Az. I limped it in and got that fixed. Stupid me. Other than what you mentioned is the LLY a pretty good motor? The one I'm looking at has had the LBZ turbo mouthpiece installed on it. I'm not sure what that is but from what I have read, it's a good upgrade. Other than that, it's a stock setup. From the looks of the truck in pictures it appears pretty well taken care of.

I do appreciate your help.

Ray

[socaltoolguy]

When were the head gaskets replaced? Did they use bolts or studs to clamp things back together?
Has the transmission fluid been regularly drained and refilled with a fresh screw on filter can?
Did the engine coolant get changed at 150K?
Is the truck bed whole or has there been a 5th wheel mount bolted on? (speaks to the engine's working life)
Has the seller been religiously using a fuel additive on every tank of fuel? ULSD diesel is not very slippery...

I have well over 230K miles on mine and replaced the gaskets at about 160K. Used ARP studs. Pulls like a freight train.

Can you give me some info on the fuel additive? I had a 2001 Duramax that we full timed with and never put anything in the tank except diesel. Did I do a bad thing? I'm just asking because I want to do right with my next truck. Also, what year trucks had to have an additional tank for the needed additive? Was it 08-09???

[rapidoxidationman]

I'm not sure what year DPF became a necessary fluid for the truck to run - 2012 maybe? Someone here will tell you with more certainty.

Regarding fuel additive, I've always used Power Service in the gray bottle. Some would say it's the bottom of the barrel for fuel additives, but I've yet to have a fuel related issue with my diesel engines and I've had 6 between cars and trucks. FPPF is seemingly a preferred brand, but isn't as easy to get here. Additive will keep the fuel system slippery and clean, something today's low lubricity fuel might not do as well as it should.

[DmaxMaverick]

DPF = Diesel Particulate Filter -- 2007.5
DEF = Diesel Emissions (Exhaust, etc.) Fluid -- 2012

[rapidoxidationman]

^this:)

[Kennedy]

2011 models have DEF

[More Power]

Of all of the Duramax 6600 engines, the LLY is mentioned occasionally as the one that runs too warm, due perhaps to changes in the cooling system and intercooler for that generation engine. Most owners don't have a cooling problem, but those who tow heavy in the high heat of a southwest summer might.

There are solutions to this overtemp issue with the LLY. The best I've heard involved retrofitting 2006 factory LBZ cooling system parts.

[socaltoolguy]

Thanks to all of you who took the time to reply. So, from what I'm gathering, I don't really have much to worry about with an LLY motor. That's great. Now all I have to do is find a truck that I can afford. One more question, At what point should miles become a factor? I realize that maintenance plays a huge roll but I am seeing a lot of trucks for sale with 175k to 200k miles. When I sold our truck it only had 70k on it. I was told that it wasn't even broken in yet. So, at what point should I say, "too many miles"?


Ray

[gary_lucas]

Thanks to all of you who took the time to reply. So, from what I'm gathering, I don't really have much to worry about with an LLY motor. That's great. Now all I have to do is find a truck that I can afford. One more question, At what point should miles become a factor? I realize that maintenance plays a huge roll but I am seeing a lot of trucks for sale with 175k to 200k miles. When I sold our truck it only had 70k on it. I was told that it wasn't even broken in yet. So, at what point should I say, "too many miles"?


Ray

I don't think this is specific to an LLY, it's legitimate advice for any vehicle. But most vehicles aren't 5-8k to replace head gaskets on.

The only piece of advice I'd give is watch out for overheat / radiator clogged up on the air side.

I have an LLY and had an overheat problem:

https://goo.gl/photos/Yhq49tzEDFz8aMza9

That was the cause, but it's not that easy to check. At this stage I pull it out every 2nd year and take a look.

I did need my head gaskets done and I'm pretty sure this was the cause.

[socaltoolguy]

Wow Gary. I looked at your pic of your radiator and I can see why you had an overheating problem. I've never seen a radiator that messed up. You must travel some crappy roads is all I can say. I had my 2001 and sold it in 2011. It had 75k on it and my radiator was clean. I will say though that I used to keep an eye on it. I figured if the front of the oil cooler and a/c condenser was clean, the radiator would also be clean. Thanks for your comment. I appreciate it.

Ray

[a5150nut]

Gary,

Those photos remind me of my old 74 350 3/4 ton running between San Jose and Paradise going through the Sacramento valley rice fields. The front of the truck would look like green fur when I got home. And for only coming home on the weekends the birds would swarm it as soon as I parked. I ran black nylon screen behind the grill and what didn't fall off the birds would remove for me.