6.6 Liter Duramax Turbo Diesel Help Please!!!

[DaneOnBass]

Hi I am thinking of buying a 2004 Glavial Concorde shuttle bus: GMC C 5500, 6.6 Liter Duramax Turbo Diesel, Allison engine with 160,000 miles...

Does anyone know the life expectancy of this engine, how good it would be for towing a trailer, or any other important facts about this engine or the actual bus if you have knowledge..

thanks a bunch!

[Mark Rinker]

Hello - welcome aboard.

The 6.6L Duramax is an incredibly reliable engine, and with regular maintenance can easily outlast the trucks they are bolted to. Elsewhere on this forum you'll find stories of 500K+ engines. I have personally sold one at 285K that ran like the day I bought it at 130K.

The GMC 5500 chassis was made for upfitting and carrying loads. As for towing, I'd say take ~24000# total weight potential - weight of the shuttle = available towing capacity, at any highway speed, over any distance or terrain conditions. Realistically you could tow up to 50% more weight under more constrained speeds, terrains, and distances.

How the shuttle was used and maintained is the whole key. If it were running all day, every day moving people about an airport for example, I'd say it had a pretty easy life. If it were off the oil fields in Alaska, carrying equipment over dirt roads in -40F temps...well...

A good thing to find out would be the age of the injectors, if they have been changed yet, etc. Injectors are an expensive, wearable item that can cost up to $4000 to replace, and should be heavily factored into the purchase price. It is not a matter of IF but WHEN you'll swap injectors on this truck, and if it hasn't been done, I'm betting you might be due shortly based on my experience with two sets (under warranty) on my 2004 C4500 Kodiak... You may have warranty coverage to 200K miles with this 2004.

Q: What is the 8th position of your VIN# ?

Good luck, lots of knowledgeable people here willing to help!

[DaneOnBass]

Mark, thank you so much for the awesome information...I am new to buying a diesel engine but have been looking for the past 6 months and am amazed at all the info I am finding out about these things.

Another question I would like to ask you is comparing the 6.6L Duramax engine with a couple other shuttles I'm looking at. Currently on my list is a '99 Chevy El Dorado 3500 shuttle with two dualies in the rear. I'm not sure the exact engine but it has an original 75,000. The other shuttle is a 2001 turtle top with a a Ford E450 7.3 L engine w/ 95,000

So my question is what is the best bet of these three engines overall comparing mileage on the engine, towing a trailer, and the year of the engine, (remember the 6.6L Duramax has 160,000 miles)..obviously things like, price, fuel injector replacement, and wear and tear is a separate issue..

Sorry, I dont have the vin number for this vehicle yet but I will try and get it for you...

Thanks again for all your help!

[Mark Rinker]

This is a subjective statement, but all else being the same, I would place the 6.6L Duramax at the top of the engines listed - based on quality and durability. Ford 7.3L is a very respectable second. '99 Chev 6.5L a more distant third.

What are the prices? If the Duramax still has its original injectors, add 4K to your budget - unless you can verify in writing that they are covered to 200K. I know my 2004 Kodiak was...not sure about 2004 GMC chassis, but think they should be under similar coverage but might have 7 year expiration.

What are the prices? The low mile Ford 7.3L might be a good choice, if similar in price to the Duramax with no warranty and 160K on the injectors.

[DaneOnBass]

Thanks! Thats the order I was thinking from the info I've been gathering. I talked to a pretty experienced Chevy diesel mechanic yesterday and he said he'd take the Duramax over the '99 any day, and that the '99 engines seem to have a lot of problems and the duramax could possibly last up to 500k miles. He also said that to replace the fuel injectors it would cost up to $6500! Is that right? He also said replacing the 99's injectors could cost the same...but he said that if very well taken care of some times you could potentially never have to replace the injectors.. any info on this Mark?

By the way, the price on the '99 Chevy is $30,000, and the price of the Ford '01 is $28,000 and the price of the '04 Duramax is $29,000..and that is also the order for lowest to highest mileage.. I am still waiting to hear about injectors.

The 8th position of the vin# on the duramax is 1...what does this mean?

Thanks again!

[Mark Rinker]

It means the engine is an 'LB7', the first production run from 2001 through mid 2004. This is a very good engine, free from lots of emissions stuff added in later years.

However, the LB7 used a 'through the valve cover' design for injectors, that adds alot of time and effort for replacing injectors, thus the higher repair bills. Add to that, the LB7s are known for short injector life. I have replaced four sets on three trucks, and the average mileage was under 150K miles.

Next assignment: Take the VIN of the Duramax to the closest Medium Duty service center (http://www.gmfleet.com/gmc/), have them 1) run the warranty history, 2) see if you still have original injectors, and 3) inquire if this GMC cab/chassis is still under the 200K, 7yr injector replacement warranty.

You'll have to do your own research elsewhere on the Ford. My thought is if the Duramax has no warranty coverage and still has the original injectors...you might be money ahead to buy the 7.3L powered shuttle, if they both have the features you need.

[DaneOnBass]

Thanks Mark! I really appreciate the help..I'm gonna check out that vin# and see what the situation is with a warranty.. I may be back to ask some more questions in my further search to find a shuttle

[Dan0530]

It means the engine is an 'LB7', the first production run from 2001 through mid 2004. This is a very good engine, free from lots of emissions stuff added in later years.

However, the LB7 used a 'through the valve cover' design for injectors, that adds alot of time and effort for replacing injectors, thus the higher repair bills. Add to that, the LB7s are known for short injector life. I have replaced four sets on three trucks, and the average mileage was under 150K miles.

Next assignment: Take the VIN of the Duramax to the closest Medium Duty service center (http://www.gmfleet.com/gmc/), have them 1) run the warranty history, 2) see if you still have original injectors, and 3) inquire if this GMC cab/chassis is still under the 200K, 7yr injector replacement warranty.

You'll have to do your own research elsewhere on the Ford. My thought is if the Duramax has no warranty coverage and still has the original injectors...you might be money ahead to buy the 7.3L powered shuttle, if they both have the features you need.

Mark is not online... My C4500 is a 2 in the 8th position of the VIN. Does anyone know what engine I have... and how does it stack up to the LB7?