Reliable 6.5td

[haakon]

I see on theese forums that the 6.5 has a bad reputation.

ive owned 3 6.5s all 99mod,and they have been good reliable engines,good cold start performance,and no oil consumption..they all have been rolling 300k kilometers...

in my country(Norway) the climate is like alaska,and lots of steep hills,the chevys with the 6.5s have all good reputation,exsept the diesel pumps..one pick up i know has rolled 1 million kilometers,stock engine:thumbsup:

no offence,but is that because we ar wery used to diesels? (moust cars over here ar diesels)
we grow up with diesels everyone starts the engine and lets it warm up at idle before driving,and newer push it unless its warmed up,and we newer push it over 2500-3000rpms,newr pedal to metal for a long time,oil change every 5000miles..

i would never push a diesel like this full trottle for too long,no matter if its a gm diesel or if its a Mercedes or WV..
i push my dump truck,but that is a Scania with a 16 litre 730hp 3500NM V8 engine(stock),alot different engine,made for going full trottle all the time..

or is the cold climate better for the engines?

Anyways over here you Americans ar known for building wery long lasting cars,Toyota is crap long before the chevys,but as i learned from i was a little boy,diesels aint race engines be kind to them,but you can push em when they are warm..
but not pedal to the metal for too long...almoust never id say..

 

[great white]

6.5's are mostly a victim of thier electronics and poor understanding of the problem in the beginning.

Pmd failures that were diagnosed as ip gave them a black eye.

Cracking blocks and engine failures from manufacturing defects in the 506 castings didn't help either.

Now that new diesels make 300-400 hp from the factory, the 6.5 is seen as an underpowered diesel as well as an unreliable one.

Gents also buy these older trucks and work em hard with minimal and infrequent maintenance, then don't understand why they break (old trucks break with proper maintainence also because, well, they're old).

Toss on top of all this the fact that they're now all pretty old and worn out and you have a recipe for a bad reputation.

Take an old gmt400 chassis, rebuild the front end, chuck in a new optimizer (if engine is bad), grab a pmd isolator (Heath, pmdcable.com, etc), stick in a new lift pump (or a walbro, raptor, airdog, etc) and an injector pump (if it's worn out) and you can reasonably expect another 10-15 years of reliable service.

There'll be a few odd issues like door pins or bad switches/relays, etc, but that can happen with a brand new truck too.

In summation; yeah, I do think they're "unreliable" in stock, old, high mileage form.

But chuck a fraction of the money you would spend on a new diesel and you've got a good truck for years.

My 98 had a rebuilt front end, new optimizer and upgraded cooling and a few other bits and hauled my 8500lb 35 foot travel trailer from the west coast to the east coast (7000kms) like this. Had a few pmd problems on the way, but that was fixed with a new Heath pmd isolator.

Not a powerhouse, but a good, reliable, capable truck...

 

[btfarm]

Once a complainer about the 6.5s finds his way to The Truck Stop, they usually start liking them much better.
One thing here that can really cause problems that you likely don't have in Norway is road salt in winter. It will really shorten a truck's life.

 

[WarWagon]

The 6.2 and 6.5 bad reputation is well earned. Even when they were new vehicles Glow Plugs and other items were simply constant trouble. As they age the blocks are almost always unfit to be rebuilt due to cracks. The only good thing about them was Naturally Aspirated and high MPG. If you could offset the parts cost with higher MPG you get you were doing well.

Being used to a diesel helps, but, so does a better more trouble free diesel engine to begin with.

You will find things on here to counter the bad rep.

 

[3500GMC]

They are as reliable as their owners allow them to be. Think about it. If you *know* the shortfalls and choose not to heed/prepare, you are quick to become a victim.

To some, regular maintenance is just too much to handle. When things fail, and any truck will have a problem sooner or later, some choose to be responsible about it, and some cry about it.

We see a lot of 6.5 negativity here on TTS because guys seek help here on their 'bad' 6.5. Very seldom do you hear of the good things. Yes, there are good things... :hihi:

 

[88gmctruck]

Everyone is correct, and 3500GMC has the theory I hold very close to my own; that a vehicle is as reliable as you make it. I regularly maintain my vehicles and do plenty of preventive measures, use quality parts, etc to keep them running strong.

In my opinion, the best thing to do is understand some of the shortcommings of the said vehicle, taking those into consideration during operation, maintenance and upgrades. Knowing the common trouble or weak parts that you can remedy is one the best approaches you can take on this.

 

[JMJNet]

I agree with everybody.

Forum is not the gauge how good something is because most people signing up and posting in a forum to solve problem without going to a mechanics.

I had a fairly reliable 6.5L TD Suburban. There are leaks here and there but that happens in my Toyota also because of old age.

I have a spare PMD mounted on a heatsink ready to go in service as needed.
A spare radiator hoses, fuses, etc.

 

[Michaeljp86]

My dad worked in a factory for years and they would get magazines about factory stuff. They had a article about a factory that always did the maintenance on their machines according to the manufacturers specifications. This factory had never had any machine break down. Id say its the same with these trucks.

My dads john deere had a few problems. If we would have read the manual and checked what we should have these problems would have never happened.

My truck has been pretty good to me. Its had some problems but they were electrical and even with the problems you could still drive it. I know a guy with a big bad 7.3L F350 who has enough money in just the transmission to buy about 10 6.5 pickups. He also has about 5k into the transfer case and has had a few engine problems. I know a guy from church whos sone has a 3500 dodge diesel, I think a 1998. He said hes had nothing but trouble with it.

From all the diesel owners I know Id say my 6.5 has been the cheapest and most reliable out of them all. They could probably out pull me any day but for tens of thousands of dollars I'll take it a little slower.

 

[WarWagon]

Factory maintenance doesn't say replace fan clutch after 5 years: it says to check cooling system. It doesn't say to replace the injectors at 100K miles.
Factory doesn't say anything about keeping the temp at 210 max...

The Gasser mindset GM crammed into the diesel has a lot to do with it's bad rep. The weak engine due to cost cutting also has a lot to do with the bad rep - aka not using forged cranks, weak crack prone blocks and heads. The expectation was 36K for warranty and 100K warranty later for the 6.5's.

The 6.2 without electronics also had issues, air in fuel from filter box, glow plugs and controllers...

The Non-GM redesign fixed some of the weak parts but kept the PMD on the IP...

 

[Michaeljp86]

Factory maintenance doesn't say replace fan clutch after 5 years: it says to check cooling system. It doesn't say to replace the injectors at 100K miles.
Factory doesn't say anything about keeping the temp at 210 max...

The Gasser mindset GM crammed into the diesel has a lot to do with it's bad rep. The weak engine due to cost cutting also has a lot to do with the bad rep - aka not using forged cranks, weak crack prone blocks and heads. The expectation was 36K for warranty and 100K warranty later for the 6.5's.

The 6.2 without electronics also had issues, air in fuel from filter box, glow plugs and controllers...

The Non-GM redesign fixed some of the weak parts but kept the PMD on the IP...

I never did like the box filter on the 6.2, poor design from the get go IMO. And I agree about the gasser mindset. I think the temp gauge scale should be set up alot different then what it is. There isnt much difference from normal temp to 210. They need to have a little wider scale there.

 

[SnowDrift]

One thing here that can really cause problems that you likely don't have in Norway is road salt in winter. .

Say it ain't so! If this is true, then I think I'll move to Norway for my winters.

(sorry to go off topic for that)

 

[Chevy Dooley]

Say it ain't so! If this is true, then I think I'll move to Norway for my winters.

(sorry to go off topic for that)

It is not true, we have a lot of road salt! At least in southern Norway.
People in this country think it is a human right to run as fast in winter as in summer ut: