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6.5 diesel opinions?

Discussion in 'The Garage' started by sled_dog, May 29, 2003.

  1. sled_dog

    sled_dog 1 ton status

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    I have negative opinions of Chevy diesels but my dad just told me where there is a 90 or so diesel pickup for sale. He said its been there quite a while so maybe I could get the price down. My dad said its fairly high mileage, guessing over 150k so what would I want to look for? What would wear out on the motor? How about Diesel hop ups? I was planning on building up the 350 in the truck I have been planning on getting(waiting on the guy but have been waiting weeks). I would have to hop up the 6.5 if I got it.
     
  2. mosesburb

    mosesburb For Rent Premium Member GMOTM Winner

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    The 6.2L and 6.5L (pre '94 electronic controls) are good motors. The mechanical pumps last a long time (compared to the electronic pumps '94 and up). There are quite a few mods available for them. GMDiesel.com is a good source of info, as well as the Diesel section of this site. There are quite a few suppliers of aftermarket goodies for them out there, you just need to dig around a bit.
     
  3. MousePowrd

    MousePowrd 1/2 ton status

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    Unless you plan on putting a lot of miles on this diesel it would probably be cheaper in the long run to stay with gas.
     
  4. ducttape114

    ducttape114 1/2 ton status

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    im very happy with my 6.5, it has all the power i need with no mods other than a K&N.
     
  5. alec78

    alec78 1/2 ton status

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    Awesome fuel mileage, plenty of power, and if taken care of the engine will last 300,000 miles!!! /forums/images/graemlins/thumb.gif
     
  6. Suburbanite

    Suburbanite Registered Member

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    I share your negative opinion of them but here's some info.

    Potential problems & weaknesses:
    * Block cracking -- #8 cylinder I think.
    * Head cracks -- from what I've read, almost universal. In other words, short of buying new, good luck in finding heads without cracks!
    * Overheating -- mainly only a problem while towing but depends on terrain.
    * Non-intercooled.
    * ~21:1 CR vs ~18 for Ford & Dodge.

    Mods:
    * '97+ cooling sys upgrade -- 130gpm (vs 80 or 100) WP & x-over with dual thermostats.
    * Intercooler -- big rig junkyard or from Dodge or Ford plus associated tubing, couplers & clamps.
    * 18:1 CR pistons (try eBay Motors) -- big bux, but with them & intercooler allows increasing boost from ~7psi stock to ~double that.
    * And the BEST mod of all! Drop in a Cummins!!! /forums/images/graemlins/thumb.gif
    (mods for the 6.5 can get expensive veeerrry quick & the engine is simply not worth it IMO. Whenever anyone mentions mods for the 6.5 I'm reminded of the 2 characters on HP-TV who blithely pronounce: "For ~$2K we picked up ~30HP" [Woo-hoo, now we're talking!!!], complete with fake [I'm getting an a**-reaming] smiles.)

    Unlike another poster, I wasn't impressed with the fuel mileage for the '95 I briefly (thankfully) owned.

    Also wasn't impressed with increased maintenance: extra oil, fuel filter replacement every other oil change (I could never figure out how to do it without making a mess. Tried various tubes but no luck.), fuel supplement (unnecesary but just about everyone I talked/typed to recommended it.) & fuel system upkeep. Diesel fuel & moisture usually means algae growth which requires a biocide treatment (or two) & 1 or more fuel filter replacements. Finally, just as a reminder, tell your Dad that winter diesel will produce ~2-3mpg LESS fuel mileage than summer diesel fuel.

    Good luck.
     
  7. Suburbanite

    Suburbanite Registered Member

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