6.2L VS 6.5L Diesels!!!???

Discussion in 'Trucks and Trailers' started by instyle, Oct 24, 2006.

  1. instyle

    instyle LawnSite Senior Member
    from Canada
    Posts: 380

    I am lookinng at a 91 GMC with the 6.2 Diesel, isthis any good, or should I be waiting for a 6.5L?
  2. lawnmaniac883

    lawnmaniac883 LawnSite Silver Member
    Posts: 2,613

    Gutless engines..................
  3. Scag48

    Scag48 LawnSite Fanatic
    Posts: 6,067

    6.2 was a terrible, gutless motor. 6.5 wasn't much better. I had a 6.2, never had the 6.5, but heard it was yet another GM screwup.
  4. mcwlandscaping

    mcwlandscaping LawnSite Gold Member
    Posts: 3,164

    350 or 454 are the engines of choice for those years
  5. Gravel Rat

    Gravel Rat LawnSite Fanatic
    Posts: 9,544

    The 6.2 and 6.5 are not the best motors made the 6.2 is a gutless pig I think it only puts out 140-150hp. The 6.5 is also gutless I drove 3500 1 ton dump 4x4 carrying cord of firewood a few times it was at the point of getting out and push. GM screwed up with those engines they were just as worse than the 6.0 PSD.
  6. TLS

    TLS LawnSite Fanatic
    Posts: 7,937

    Good point.

    The 6.2/6.5 is old tech diesel. Not the most reliable, and as others have said, harldy powerful enough to get out of it's own way.

    Only positive is, they were capable of 20mpg highway, where the 350/454 struggled to get half that.
  7. Scag48

    Scag48 LawnSite Fanatic
    Posts: 6,067

    The mileage on the 6.2 was great! But, being a 350 gas motor block converted to a 381(?) diesel just wasn't the best move for power and reliability. Although, the manual says that the engine was designed with fuel economy in mind, not pulling power, so maybe GM's only true mistake was the reliability.
  8. TLS

    TLS LawnSite Fanatic
    Posts: 7,937

    That info is incorrect.

    The 6.2/6.5 engine has NOTHING to do with ANY gas engine.

    The 6.2 was pretty reliable if used for what it was intended. It's when the turbo's were added that problems arised.
  9. Scag48

    Scag48 LawnSite Fanatic
    Posts: 6,067

    I'm pretty sure I've heard from numerous sources that the 6.2 was a 350 gas block with a diesel head. And yes, the 6.2 reliability was terrible, even when they were naturally aspirated. I dropped thousands into the one I had and I let go of it at 115K miles. No heavy towing, just a mowing trailer.
  10. Gravel Rat

    Gravel Rat LawnSite Fanatic
    Posts: 9,544

    The 6.2 was a diesel the 350 olds was the converted gas engine you took the plugs out and installed injectors. It was a real POS it started Chev with the bad name then it progressed from there. Hey atleast Ford and Chevy offered diesel P/U trucks back in the early early 80s. Chevy started the 6.2 Ford started with the 6.9. Not big power engines but it was a start then Ford changed to 7.3 IDI had problems with cavitation but was controlable. The 6.2 ran till 88 late 89 then Chev produced a 6.5 it wasn't the greatest it used a timing chain to run the injection pump. Then the newer 6.5s had real injection pump problems. The 6.5 was riddled with problems they didn't produce big power but they got decent fuel mileage.

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