6.5 diesel. What was wrong with them?

[Dacotensis]

I've seen some of these Gm's s over the years with 4-600,000 Km on them.
What were they good at?
From what I've heard from guys is they usually get a tune up around 300,000 and go again.
What were the pitfalls of this engine?
Are they an economic engine?
Good for pulling?

Would it be a bad move to get into something like a 98 with 350K?

How did the drivetrain stand up?

[sako1]

Noisy and slow.They do get respectable milage.They have a hard time starting if its cold at all,walk in front of one with a slurpee in hand and you better hope its plugged in.Heads are prone to cracking.Pmd's fail all the time.Drivetrain is solid.

[bigbadbrown]

Noisy and slow.They do get respectable milage.They have a hard time starting if its cold at all,walk in front of one with a slurpee in hand and you better hope its plugged in.Heads are prone to cracking.Pmd's fail all the time.Drivetrain is solid.

I second all of this. Although my truck had no problem cold starting.
Head cracked at 500000. It was my fault though. Was trying to pull a tractor back to the shop that broke down. Always keep a spare pmd and anytime you have any running or starting issue change it first.

[bison]

Nothing wrong with these 6.5 diesels, they were build for fuel mileage not for power but with the proper mods they hold their own in pulling good seized loads.
Biggest issue was as being said PMD and OPS or LP failure and subsequently injection pump failure because of it. and most of all dealer non knowledge how to properly deal with it.Most of the above can be easy prevented once one knows how.
300.000 miles is pretty well the average life expectancy but there are quite a few still running at 400 K +
I would not pay much for a high miler cause changes are you're in for a rebuild engine shortly. The 4L80 tranny's are pretty good
97 and up have the 506 block with the piston cooling, these blocks are prone to main web cracking.

i have 3 of these 6.5's,and one 6.2 actually it is all we drive, both me and wife have a 98 and i have the 2 older ones for farm use.
Bought them all used paid no more than 4.5 grand or less a piece
Cheap and reliable

My 2 c

[sewerrat]

Had on old '98, I never really had an issue, I sold it when it had just below 300 thou.k on it.

I mainly used for pulling our fifth wheel , but climbing any hill she was a slug.

At least it sounded like a real diesel. It is loud and stinky when you fire it up.

[spoiledsaskhunter]

i had a '94 and a '96..........worst rucks i ever owned. wudn't pull ur p***k out of a lard pail. heater guages were going to hot all the time, then the fan wud kick in to cool them back off. when that happened, u had to step on the gas just to keep them going, they were so gutless.

put 3 pumps in the '96 and 2 in the '94. these two trucks were the reason i have never owned another gm product. if u buy one, don't plan on pulling anything. if u don't mind fixing repeatedly, they do drive beautifully and r very comfortable.

[bison]

i had a '94 and a '96..........worst rucks i ever owned. wudn't pull ur p***k out of a lard pail. heater guages were going to hot all the time, then the fan wud kick in to cool them back off. when that happened, u had to step on the gas just to keep them going, they were so gutless.

put 3 pumps in the '96 and 2 in the '94. these two trucks were the reason i have never owned another gm product. if u buy one, don't plan on pulling anything. if u don't mind fixing repeatedly, they do drive beautifully and r very comfortable.hmm,..you musta have had bad luck and/or a bad mechanic with no knowledge

It ain't no semi but my 98 pulls just fine whatever i hook behind it,..getting it to stop is another story ;)

[spoiledsaskhunter]

i don't remember ever talking to anyone about them that did not have diesel pump problems......thankfully the pumps were still under warrant, as if i recollect they were worth around $1800 each.

[bison]

The DS4 injection pumps gave/give seldom problem by themselves.
The PMD ( Pump Mounted Driver) as the name says is mounted on the pump.
When the PMD failed the dealers routinely changed the whole pump till GM figured out all these IP returns was costing them to much and then they recommended just changing the PMD.( the dealers did not have a clue)
That PMD is on a rotten location and swapping it is a couple hr job.
The reason these PMD failed was 60% of the time by overheating trough a lack of cooling caused by a lack of fuel going trough the pump.
The fuel supply had its own problems caused by either the OPS or the LP failing(both failure prone parts)
Altogether a sequence of problems that could largely have been avoided among other little changes by installing a fuel pressure gauge in the cab to monitor fuel supply and catch an impending problem before it leaves one stranded and remote mounting the PMD on a heatsink so in case of failure it would be a 5 min job to swap a spare PMD along the road that even my wife can do instead of a tow to the dealers lot and a $1000 + dollar bill.
PMD's alone used to be a $7-800 item but aftermarket ones can be had for a couple hundred( see it as carrying a spare tire, don't leave home without it ;)).

BTW, the dodge Cummins with the VP44 electronic injection pumps deal with the same problems, internal PMD failure caused by lack of fuel trough faulty lift pumps. Again, having a fuel pressure gauge could prevent most of these problems and save thousands in repair bills.:)

Knowledge is money in the bank.;)

[Drewski Canuck]

Sad part is that GM had the world by the horns when it bought out ISUZU. The Duramax was based on the ISUZU prototype, which was by all standards an incredible engine, but too heavy for the GM front end. Hence the lightening job GM did to the Isuzu, and the history of problems afterwards.

In a perfect world, a Ford F350 with a blown 6 L diesel would be mated to a Cummins 5.9 24 V with the Bosch single rail injector system, turbo and pump.

This would solve Ford's Navistar problems, and Dodge's soft front ends.

As for GM, they just don't get it that truck people want something durable. Maybe at some point, but GM's history is one of cutting corners when it comes to diesels, all the way back to the old 350 / 6.2, the 6.5 and the present power plant.

Drewski

[silver]

I have a 96 chev with the 6.5, at 344,000 it got thirsty for anti-freeze. Head or head gasket I suppose. I still like the truck, would put another one in it if I got an engine at a reasonable price. The fuel mileage was in the high teens and the power was so-so. It would pull my fifth wheel or my skid steer but you better not be in a hurry.

I wouldn't recommend you buy one, I would go for a ten year old duramax if I were you. By now most of their bad habits/weak points have been fixed, and there doesn't seem to be an end in sight for them. I have been looking for another 6.5 and ran across a ten year old duramax with 750,000 on it at the wreckers.

Good luck.

[bison]

Every make/model engine has it's issues, all of them brake down, some sooner, some later
Dodge Cummins and Ford aint any different than GM.

One always hears about the failures but not to much about the success stories.
Having said that i think the ford 6 ltr diesel tops the list for costly failure rates. :scared0018:

[ali#1]

There is a 94 gm for sale in edmonton with the 6.5 and 155000 km but the dealer wants 5g for it and the side is wavey and a few spots of rust on it.

[bison]

The dealer probably traded it in for a grand if that
That truck is 20 years old!,... I would offer him $500 just to pi$$ him off.

I bought 18 months ago a 98 6.5 with 212 K on it , no dents, rust free.
$4500.
my honey's daily driver

[ali#1]

The dealer probably traded it in for a grand if that
That truck is 20 years old!,... I would offer him $500 just to pi$$ him off.

I bought 18 months ago a 98 6.5 with 212 K on it , no dents, rust free.
$4500.
my honey's daily driver

I checked and he dropped the price to 3800.

[bison]

offer him $380,..see what he says.:)

Oh,..Tell him that is with a full tank;)

[ali#1]

offer him $380,..see what he says.:)

Oh,..Tell him that is with a full tank;)

I am not in the market right now maybe in a few months. I wouldn't pay more than 3 g taxes in for a 94 though.

[Taco]

offer him $380,..see what he says.:)

Oh,..Tell him that is with a full tank;)

Your "old country" side is showin'......