Known issues on 05 Sierra 2500HD Duramax?

[Josh Wilusz]

Ok everyone I am by no means new to the diesel world. I worked on the HMMWV while serving in the military which was essentially an old Duramax motor. The problem with those were heads and head gaskets mainly. Sometimes an injection pump. Ok now lets look at what I got. I currently have an 02 silverado 2500HD with the 6.0 engine in it and it currently has 188000 miles on it and runs strong now that I fixed a fuel issue. I just saw a nice looking 05 Sierra 2500HD with a Duramax engine in it. I was hoping someone could help me with KNOWN problems on this truck. I plan to go test drive it on friday and want to know what I should look at while there considering this would be the newest vehicle I have ever owned and my first diesel I have owned. I know there is a harness issue with 2 and 7 however they have made a replacement pigtail that is supposed to fix that problem. I wont be towing heavy loads so I won't have to worry about the overheating under extreme loads. I have heard the water pump is something that will go out fairly quickly between 80,000 and 100,000 miles. Can someone help me out with anything else I am missing because I don't want to trade my good truck for something that could screw up.

[davester]

Don't know about issues with the engine, but look in the drivers wheel well at the frame, and check out the brake lines there. they tend to rust along there and where it goes over the frame to the ABS controller under the cab below the drivers seat. They also rust out over the gas/diesel tank for the rear line, but you can't easily see the line there. It's not the end of the world, but new pre-bent lines start at about $100 and go up, and installing them takes some time.

 

If you can, bring a odbii code scanner, take it for a test drive and then check for codes [they won't necessarily show up, it may take a longer drive, but some might, and some sellers will clear the codes before showing the vehicle].

 

And is there any reason for this swap? The diesel will cost more in general maintenance as well as when problems occur, and the trucks are about the same age. And gas trucks tend to handle shorter trips better, while diesels work better for longer trips and towing heavier loads.

[Josh Wilusz]

I really just want to go with a diesel. The MPG is way better based on what I have seen. I drive about 60 miles a day for work and driving my truck I currently have I can go about 3 days at best before having to fill up. I have a programmer on the 6.0 for better MPG but let's face it they aren't known for great gas mileage. I did look at prices for replacement parts and was astonished at the price but from time to time I do some hauling and it seems like more and more I am doing it. I have a feeling though once I upgrade the calls will stop coming.

[Chevor]

Search around Dieselplace.com. A lot of info on older diesels

[Josh Wilusz]

Thank you.

[jake111]

I usually warn that while these are GREAT trucks, they have a LOT of potentially big problems. If you do your own work, then they can be manageable. That said, I took mine on a 13k mile trip in 2014, I just got back from a 3300 mile trip, and my truck was flawless. But, I’ve had it since new, have never overheated (and added an aux radiator to make sure it doesn’t), have never ran a tuner (which can also lead to transmission problems), and I live in southern California so there is NO rust under the truck. At 107k miles, I replaced the water pump, serpentine belt (and idlers and tensioner) . . . not because there was a problem, but because I don’t want to wait for the problem to show up when I’m on a trip.

 

Unless you need the diesel to tow or haul a load, then it’s hard to justify the diesel. If you drive 60 miles a day and want better mileage, then a small economy car (I’m partial to Japanese makes for this) is the way to go. That said, here’s a partial list of issues with the 2004.5/2005 LLY Duramax trucks . . .

 

Short or Long bed? Standard, Extended, or Crew cab? Short bed has a 26 gal. tank; long has a 34 gal. tank. Crew cab with long bed has a 2-piece driveshaft and the carrier bearing/mounts can be a problem.

 

Wiring harness – may rub through where it goes over the alternator (or is it FICM?) bracket on front of motor, passenger side. It needs to be protected where it rubs, usually with a piece of heater hose. Other potential chafing spots exist, and some connectors can have contact problems.

 

Injector connectors - #2 and #7 are common culprits, but it can happen on any cylinder. They can be replaced or “ice picked” to make sure they make a good connection.

 

Overheating – worse on long, hot climbs (especially in the west). An auxiliary radiator kit is available.

 

Head gaskets – mostly a problem if it’s been overheated or had a tuner. Expensive to fix ($6K?) and should include replacing torque-to-yield bolts with ARP studs.

 

4x4? – If so, magnesium transfer case can get a pinhole from “pump rub”, leak out the ATF, and ruin the transfer case.

 

Water pump – failure-wise, no worse than any other vehicle, i.e., will probably have a problem sometime after 100k miles. More difficult to change than most (must remove harmonic balancer on crankshaft; o-ring on tube from pump to thermostat housing can be tricky).

 

Serpentine belt idlers – usually make noise or bearing gets sloppy before going bad. Not expensive or hard to change (probably should do tensioner, too, along with serpentine belt).

 

Fuel filter head – pump may leak, or need new o-rings for pump to work. BTW, fuel filters are expensive and can be tricky to replace. Some have had problems with certain brands/types of filters, especially the ones with plastic housings.

 

Some problems will be worse if the truck has resided in the rust belt, e.g., rusting brake lines, abnormal brake wear, speed sensors affecting ABS (truck could be hard to stop).

 

Automatic Climate control system (if so equipped) is, um, maybe too smart and does stupid things when it thinks an actuator door is “out of range”. It may be reset by turning off/on (mine does, and has since new), or it may require changing an actuator door which is a difficult task.

 

Allison 5-spd automatic – a great transmission, but can have failures if engine has power tune added. Also, it originally used Dexron-III ATF which is no longer available (or hard to find) with that spec. GM replaced with Dexron –VI ATF but there may be a seal problem if used. If the truck has been serviced at a dealer, it will almost certainly have Dexron-VI. It should be replaced with a “synthetic Dex-III” (e.g., Mobil 1 Fully Synthetic ATF “for 2005 and older GM”) or TES-295 (Castrol Transynd, Mobil Delvac ATF, etc.).