Hello all!

I am looking into buying a 2500/3500 series truck and I thought since I am a GM guy now I might as well keep up the trend and get a GM truck... although the Dodge diesel trucks are equally as appetizing. My budget for a truck will be around $5500 so I probably be looking at a 6.5 equipped truck. I have a few questions to start off my research...

1: What year(s) have the best 6.5 setup? I don't care if its electronic, mechanical, more sensors, less sensors... etc. I am simply looking for the most robust 6.5 setup available. What are all of your opinions?

2: I guess this question somewhat relies on the answer to the first one... but what is a rough estimate of mileage out of a 6.5 between rebuilds?

3: Again, probably very relevant to question 1... What are the most common things to go wrong with a 6.5 setup? This information will be most helpful when I go out and start searching for a truck so I can weed out the bad ones!

4: What kind of fuel mileage (mpg) does one tend to get out of a 6.5 in a 2500/3500 chassis?

5: What part of the VIN# denotes a turbo equipped 6.5?


This is all the questions that come to mind for now. Thanks for your assistance!

1. 92-93 Mechanical Injection is easier to adjust, Elec. Inj. is good, once PMD is moved out of the engine heat. 97+ blocks have oil piston spray, which is rumored to cause block to crack due to extra passages. They also however, have better cooling, which is an easy recommended upgrade to do to earlier models.
2. Varies from under 100k mi to over 400k mi.
3. SEARCH function is great for this!
4. avg. from 15-22 mpg
5. Virtually all 6.5 are turbo. 8 place VIN S has EGR, VIN F has no emission controls

P.S. :welcome:

IIRC, VIN P is non-turbo.

When i set out to get a dually, i limited my budget to $5K total. Bought a non-running '93 6.5 TD 3500 ext cab for $2000. Got it running in 30 minutes, had to replace the tranny (4L80E), injectors, balancer and pulley. Also added guages, GM-8 turbo, 3" downpipe straightpipe exhaust out the back and glows. Have $4200 in it now and i'm pretty happy with it as my towing truck. May have to replace the IP in the next year, but overall works well. I have a dual-axle car trailer, with car about 7000lbs. It will pull it well on level ground, up hills it will drop to 60mph but still get you there. Pretty hilly around here.
Don

1. 92-93 Mechanical Injection is easier to adjust, Elec. Inj. is good, once PMD is moved out of the engine heat. 97+ blocks have oil piston spray, which is rumored to cause block to crack due to extra passages. They also however, have better cooling, which is an easy recommended upgrade to do to earlier models.
2. Varies from under 100k mi to over 400k mi.
3. SEARCH function is great for this!
4. avg. from 15-22 mpg
5. Virtually all 6.5 are turbo. 8 place VIN S has EGR, VIN F has no emission controls

P.S. :welcome:

Id go for a 96 (maybe im biased, but i like them the best).
Make sure you get a truck with a vin "F" engine. (No EGR).
I make 22mpg highway, with worn injectors and stock exhaust. 4" exhaust and new injectors would give me more power and milage.
As long as the VIN is "F" or "S" it will be turbo. Look at the 5th digit in the VIN number for the engine code. I dont think any of the TRUCKS 94+ were non turbo, but might have been some vans that were non turbo past 94. Not sure on that. My truck has 229,000 and no signs of stopping anytime soon. Somone posted recently about their 6.5 hitting 400,000 miles. I dont think most make it that far but if you take care of it its very possible. The PMD, oil pressure switch, and crank pulley are the most common problem areas with the 6.5's. Vacuum pump would be next in line. Many people eliminate that with no problems (unless you have a vin "S" engine).

Hope this helps.

Hello all!

I am looking into buying a 2500/3500 series truck and I thought since I am a GM guy now I might as well keep up the trend and get a GM truck... although the Dodge diesel trucks are equally as appetizing. My budget for a truck will be around $5500 so I probably be looking at a 6.5 equipped truck. I have a few questions to start off my research...

1: What year(s) have the best 6.5 setup? I don't care if its electronic, mechanical, more sensors, less sensors... etc. I am simply looking for the most robust 6.5 setup available. What are all of your opinions?

Not sure there is any clear consensus on any one year better, or worse than any other. Personally I would be shopping for low mileage and good body condition, regardless of year. Stuff wears out the farther it goes.

2: I guess this question somewhat relies on the answer to the first one... but what is a rough estimate of mileage out of a 6.5 between rebuilds?

GM engineered for 300,000 miles between rebuilds, your mileage may vary.

3: Again, probably very relevant to question 1... What are the most common things to go wrong with a 6.5 setup? This information will be most helpful when I go out and start searching for a truck so I can weed out the bad ones!

Look in the FAQ, I'm pretty sure there is a thread there devoted to this very topic, things to look at, feel, etc

4: What kind of fuel mileage (mpg) does one tend to get out of a 6.5 in a 2500/3500 chassis?

Depends on driving habits mostly, and overall health of the power train, but do a search, this topic comes up almost every week.

5: What part of the VIN# denotes a turbo equipped 6.5?

8th VIN digit F or S is turbo, P is N/A. All 3500 and the vast majority of 2500 would have F. S is the light duty emissions, with EGR.


This is all the questions that come to mind for now. Thanks for your assistance!...