Are are the deisel in square bodies?

[JHT67]

My dad has been looking at some trucks with dump beds, and has come across some deisels; now I've heard they weren't good motors, but neither one of us knows anything about them.

[JHT67]

Proof reading is a good thing; title should say "how are".

[allengator]

They didn't have a very good reputation at the time...
But knowing nothing about diesels, I cannot confirm the accuracy of that reputation...

[Valarius_Starchaser]

Cons include but are not limited to no power, unreliable, cracking blocks if turbocharged and overheating problems

Pros I've got nothing....

[wildwilly4x4]

I daily drive one, and have had several. Have seen more than one with over 400,000 miles. About the same power level as a 305, with much better mileage. Not uncommon to get 20+ in the mpg. very reliable if you don't try to make it a cummins. I have a 6.5 turbo on mine that's runs @ 5psi boost....makes it almost as powerful as a stock 350, with more torque.

[Cowdogpete]

I had a couple back in the day...

They were decent engines for highway purposes. Not big on acceleration, but would run great when you got up to speed. Really good fuel mileage.
Poor performace for pulling heavy trailers.

THey used to eat batteries and starters too.

After driving modern diesels, i'd be hesitant to go back to those old 6.2s.

[hatzie]

Depends on what you are looking for.
I have three of the 6.xL trucks. Two 6.5L and one 6.2L
I haven't had problems with the PMD on my 2000 GMC. I got her at 40,000 miles. I removed the PMD from the pump, filed off the corrosion on the mounting pad till the surface was smooth and straight edge flat, and reinstalled the PMD with thermal paste rather than the thermal pad.

The 6.xL AMG Detroit engine is not a hot rod it's a light duty diesel. If you want a hot rod diesel get a Cummins.

My military 6.2L NA is 165HP and 330ft-lb of torque. Noticeably better than a 305. The 6.2L gets 18-20mpg CITY-HWY with the TH400 and 4WD.

My 76 6.5L NA is a little better power than the CUCV 180HP and 360ft-lb with roughly the same fuel mileage as the CUCV. Even with OD it still only gets 17-19mpg CITY-HWY.

My 6.5L L65 Turbodiesel in my GMC is 215HP and 440ft-lb of torque. Mileage is on par with the 5.3L LS4 in my Impala that has 90more HP and 110 less ft-lb of torque. She gets 19 in town and 23 on the highway.

All three of these trucks are dead reliable. I change the fuel filters annually, oil filters every 5K, and the oil when Blackstone tells me they need it. They all have Frantz or FS2500 Bypass filters on the oil so it stays reasonably light colored.

The cracked blocks were from folks that ignored the fact that the harmonic damper and damped accessory pulley wear out in around 100,000 miles. A Fluidamper will fix the balancer issue permanently on both and the damped accessory pulley is easy to replace on the 6.5L.
Cracked heads from the valve seats into the cooling jacket are available on all emissions era vehicles not just diesels.
The Series 80 fuel filters used on the diesel squares were difficult to service and maintain. The 1995-2000 GM Stanadyne Fuel Filter Manager mounted in the intake valley is the fix.
The pre 1985 glow plug controllers are unreliable at best. Upgrade to an 85 up glow controller.
Glow plugs have come a long way in 35 years. PTC glow plugs, that weren't available in 1978 or even in 1995, are more reliable and don't burn out and swell up.
Bosch Poppet injectors are easy to service yourself... if you have patience and can pay attention to small details. That rules out most folks under the age of 35 and many under the age of 45. I usually do an injector service every 100K. They don't put up with dirt so clean up the engine bay before you pop off the lines.
Despite what the veggie oil crowd will tell you they don't put up with burning raw veggie oil for very long either. I've flipped 10+ trucks in the last 25 years buying poorly running veggie conversion abortions and bringing them back to stock for proper diesel operation. I always ran a compression check and passed on the ones that were not up to snuff. New Harmonic Balancer, New Lift pump, Updated 1995 glow controller, Updated 1998 fuel filter manager, 8 reworked injectors, and 8 up to date glow plugs along with a proper douche of the fuel tanks and most of em took off just fine. New Thermostats, fresh fluids in everything and, usually several new hoses and belts. I always gave the buyer the option of upgrading to a Fluidamper for the retail cost of the damper (wholesale to retail paid for my install time). Most of these trucks are still in operation.

[redneckwheelman2]

pretty much sums it up. other then since they are an indirect injection motor they have a high compression ratio. around 22:1 if i recall so the motors run hotter and get hotter easier. with the old cooling system they had on them pre 1997 they only had 1 thermostat and a standard flow water pump. they can run up the temp gauge rather quickly with a dirty radiator or weak fan clutch or old thermostats.
i had a 1998 6.5 for a couple years so i did my fair share of maintenance/ fixing it.
the 6.2 and early 6.5 are mechanical injection so you dont have to worry about the PMD (pump mounted driver) which have a tendancy to burn up and leave you stranded.

they do have a bad rep because of there problems, but the parts are as cheap as youll get for any diesel pickup. and they're pretty easy to work on, not alot of things in the way to do glow plugs or injectors, think i did injectors in my 6.5 for the same price as 1 duramax injector costs. but if youre looking for a modern type diesel performance its not the motors you should be looking at. with a bunch of performance parts and $$ you can squeze 300-330 hp out of them but thats around there power limit i believe.

gotta love the sound of a straight piped 6.2 or 6.5. definitely unique,

[AtomicYJ]

2.5 years ago I bough an '83 K-10 with a 6.2 diesel and an SM465 4 speed. Fixed it up some and drove it form Washington to Georgia without issue. Got about 18-20 mpg, was ok with the power level, really enjoyed it. Did all the maintenance. Exactly 20,000 miles after I bought it decided it only wanted 7 rods and the 8th left violently through the oil pan. Truck now has a 350.

[barry1982]

I own at least ten square body diesels. Have been using an 82 1/2 ton 4 x 4 6.2 diesel as a farm/hunting/fishing truck for 20 years. Have a couple Suburbans, a Blazer and numerous pickups. All 6.2's. To sum it up, if you like driving fast, passing a lot or towing heavy trailers, the 6.2 is not for you. I like the 6.2's because of the fantastic fuel mileage they make. Used to run 350's and 305's. Neither hold a candle to the mileage of a 6.2. If you warm them up a little before driving and service them regularly they last a LONG time. Injector pumps last about 120000 miles. I commute 70 miles a day for the last 30 years, and have wore out a few of these trucks. Not uncommon to get 400-500 thousand miles before overhaul. Have had a couple 6.5's, they were dependable and more powerful, but I prefer the mechanical pump 6.2's