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What Typically Kills the 6.5?

Big T

Big T

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I just returned from a 2K mile vacation camping trip driving my son's '95 Suburban. My 1999 did not make the trip as I discovered a leak on the inner boot of the driver's side CV half axle while doing an oil change before the trip.

Due to the time of the year, flyfishing was limited to 1/2 day in AZ and that was basically a waste of time. So the wife, the dogs and I did a lot of geocaching, offroading, camping, site seeing (north rim Grand Canyon, etc.) and driving the truck. The truck ran great, even had that beautiful diesel knock from the -1.94 TDCO setting while idling in 16 degrees and snowy weather at the North Rim of the Grand Canyon. I mean it sounds like something is going to break through the block on the driver's side, but completely disappears above idle speed. No more than normal white smoke at start up.

April with Webley and Coventry at North Rim:
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North Rim view through the snow:
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April with Webley and Coventry at Imperial Point:
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Obligatory truck photo at Vermillion Cliffs/Lee's Ferry:
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Navajo Bridge photos:
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Vermillion Cliffs:
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North Rim Views:
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Best part of the trip: no crowds.

All the talk on this forum and the many miles driving, got my mind thinking about what typically gives out on a 6.5 in a normal death? Do they experience a normal death or do they grenade? How many IPs do you go through before death to the 6.5? How many miles can one expect to see from a properly cared for 6.5?

Again the truck ran beautiful. Got home Saturday afternoon, unpacked and promptly installed the new axle on my 1999. Took me a little more than an hour. Would have been shorter, but I could not remove the bolt from the stabilizer as the bottom part of the bolt is bent at a 30 degrees angle below the bottom nut. So it took a little shimmying and limbo dancing to get it in.
 
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looks like a fun trip. IMO what typically kills most 6.5s early is heat. People ask way to much from a stock 6.5 without any mods. After the warranty on my IP I've only installed 1 on my 96 and have 234k on it. I think the last one would have lasted longer if I would've started adding oil to the fuel. It lasted aprox 100k.
 
Well the '95 has the Heath cooling upgrade and it performed as advertised. Though I was not towing, I did run it up some good grades at 75 mph and the highest the coolant temp went was 200. I did have the EGT briefly at 1200 and the coolant temp was at 190. Running hot was always a problem with the '95, but I addressed it early on with the '97 HO water pump and the dual crossover housing. Then a 120K miles later, it got the Heath Cooling Upgrade. The engine does consume about a quart of oil every 3K miles, but I'm told that is normal. I did the blowby check and that is normal.
 
Great pics-thanks for sharing!

I'm also glad to hear you got yours all fixed up- it's apparent you guys take care of your burbs yourselves!

Which brings me to my top three ways to kill a 6.5:

3) neglect your maintenance. Leaky fittings or hoses, dirty filters, cracked boots or balancers, worn-out fan clutches and tired thermostats, or contaminated fluids all take their toll. Doing your own maintenance and going through the diagnostic checklist every so often gives you the opportunity to keep those little things from becoming big things!

2) overwork/abuse: the 6.5 is a light-medium duty diesel... It was not designed to race at high rpm, it was not designed to pull huge loads in tough conditions. Pushing out of the performance design envelope - without doing the right modifications to expand that envelope - will kill it, sooner or later.

1). Heat. The 6.5 is not a good cooling design, and heat damage to your engine is like sun damage to your skin... It's cumulative. Every time you overheat your engine, you're putting another nail in it's coffin.

One old guy's opinion... Worth every penny you paid for it :)
 
Thanks JiFaire for the comments about our maintenance on our 'Burbs. Owning a diesel boat pushed me there on the diesel maintenance. Owning a 6.5TD cinched that diesel deal. These trucks are not my Honda:hihi: They're not for everyone, but once you get through the issues and know their limits, I think they can provide many happy miles. It was those happy miles on this trip that got me to thinking what would kill the 6.5. Because it was running so great, I had forgotten about all the work I've done and money I've spent to address the heating issues. It's been a great project truck for my son to learn diesel work. He and his wife love the truck.

Other than my ATT and Performance programming difference, I did note that his brakes stop way better than mine. We replaced his front and rears about a year and a half ago. I just replace my fronts, among other things up there. I did not touch the rears. Did not even bleed the rears and wondering if I should do so? Over this winter, if you can call it that in SoCal, I plan to replace the entire rear brake system. After the horrors of the front end, I dread what I'll find back there.
 
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It's amazing how they built those bridges....

I agree with AK about his 6.5 comments 100%

If the RED area of the temp guage was at 220 instead of 260, the blocks would be better off.

If the PMD never stalled on all these the reputation would be better off.


HOwever, they wouldn't be as cheap.

Our Militiary, the best in the world, depends on the 6.5, and so do I.
 
Great pics thanks for sharing.

I am no diesel expert buy any means but I would also think HEAT.

The biggest issue IMO is the miss leading information that was supplied by GM. Look at where GM placed the red mark on the engine coolent OEM gauge, WTF was GM thinking?

I also believe most of the public thinks..."it's a diesel" it can pull anything, alot of uneducated 6.5 owners out there that only come to this forum or others, me included, after they break something...:rolleyes5:

Scary Matt...I type slow & great minds think alike!
Matt Bachand said:
If the RED area of the temp guage was at 220 instead of 260, the blocks would be better off.
Click to expand...
 
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Taking them down for a rebuild and looking for cracks kills them.

Lets see. I have a parts collection from 3 beyond rebuild 6.5's...
  1. Fan clutch killed 1. Cracks in mains meant block was scrap. (I hate worn out fan clutches even more now!)
  2. Worn bearings and blowby was the 2nd. Crack on head bolt hole and block was scrap.
  3. 3rd was the #8 injector failed and melted the piston. Holes in the cylinder from the rod was reason #1 for scrapping the block. But wait there is more! Cracks in the mains was reason #2. Possible the piston/injector failure caused the main cracking.

So of 3 engine needing a rebuild - all 3 were worth ~$75 as scrap metal due to cracks. And these were the 1995 and 1993 block years. (Some Dodge Cummings blocks also share our misery with cracks or KDP's... Something will kill it someday.)
 
Crankme69 said:
Great pics thanks for sharing.
Click to expand...

I asked the wife what was the spot on the camera lens in the first pic? She said it was fish guts.:rolleyes5:

We had been using her camera for most of the trip, but her battery died at the North Rim. Then out came mine, fish guts and all.
 
JiFaire said:
Great pics-thanks for sharing!

Which brings me to my top four ways to kill a 6.5:
4)ChrisK1500 beat it to a catastrophic Death... :rofl:

3) neglect your maintenance. Leaky fittings or hoses, dirty filters, cracked boots or balancers, worn-out fan clutches and tired thermostats, or contaminated fluids all take their toll. Doing your own maintenance and going through the diagnostic checklist every so often gives you the opportunity to keep those little things from becoming big things!

2) overwork/abuse: the 6.5 is a light-medium duty diesel... It was not designed to race at high rpm, it was not designed to pull huge loads in tough conditions. Pushing out of the performance design envelope - without doing the right modifications to expand that envelope - will kill it, sooner or later.

1). Heat. The 6.5 is not a good cooling design, and heat damage to your engine is like sun damage to your skin... It's cumulative. Every time you overheat your engine, you're putting another nail in it's coffin.

One old guy's opinion... Worth every penny you paid for it :)
Click to expand...

Fixed it for ya...:D
 
I'm a firm believer that synthetics help keep them on life support for several more miles than dino.

Synthetic runs cooler for one thing. Proven to me by a racing friend many years ago.

My 94, which was run on Dino til recently doesn't carry the oil pressure that all the others that have been run on synthetic for most of their lives do.
 
The '95 burns a quart every 2500 miles, so synthetic would get very expensive and I could never balance the cost by increasing the oil change interval. Now on my '99 it does not burn much oil and synthetic has crossed my mind.
 
Big T said:
The '95 burns a quart every 2500 miles, so synthetic would get very expensive and I could never balance the cost by increasing the oil change interval. Now on my '99 it does not burn much oil and synthetic has crossed my mind.
Click to expand...

The 96 uses a quart every 3 to 4000 miles. Seems like it has ever since we got it.

That was about the milage we used to change dino oil. I'd rather dump in one quart than 10 for a change.
 
Crankme69 said:
I also believe most of the public thinks..."it's a diesel" it can pull anything, alot of uneducated 6.5 owners out there that only come to this forum or others, me included, after they break something...:rolleyes5:
Click to expand...

Man-O-Man isn't that the truth. For this old fart anyway...:eek:

Art
 
so the 99 stayed home because of a ripped cv boot? I had a ripped boot, clean in two, drove it every day and plowed two seasons with it before it started hinting at making noises. I had spares at home (thanks Joey D!) so I just left it alone. Couldn't believe how long it lasted after the grease was washed out of there by salty water and mud. I always thought a ripped boot was the kiss of death, maybe for a front wheel drive 4 cyl, but mine held up fine. Earned a few grand plowing and got my moneys worth out of it. And actually, it never did get loud or fail. The opposite side went bad and started clacking, so I changed them both at once.
 
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