The death of a 6.5 Turbo diesel.

Well a few days ago I was bragging up my 94 GM- 6.5 TD farm truck and now I must revisit my comments. After 165K miles it has died. The starter turns, but the crankshaft doesn't. After pulling the starter I observed that I can spin the flywheel and the crankshaft at the front of the engine does nothing. The worst part of it all is that, it was making an awful noise coming home the other day, but it made it home. No oil pressure drop and no overheating heating. My next attempt to start it however failed. No use fixing it, so I will parts it and move on. The moral of my story is "Beware of the 6.5 turbo diesels". When they are running well don't brag about it.

Broken flexplate?

It might not be that bad. Could be broken bolts at the end of the crank too.

Hope for the best, expect the worst. I have torn down 4 and all had a broken crankshaft. One quit running with a terrible noise but the other 3 were running rough with an unusual noise, until they were shut off. Then, no start. After sitting for a while, 2 got a Cummins conversion but the other 2 were sold as-is. None were mine.

I am not sure but I think that the 6.5 is a redesigned 6.2 diesel. The 6.2 diesels around here would break the crankshaft in the back main bearing. We found that you needed to change the vibration dampener every 100K and then they would not have this issue. I bet that the noise you had while driving was caused by the dampener going bad. The outer steel will rotate on the rubber isolating layer. This makes it out of balance.

It does not take long for this to happen. I had a Chev 6.2 that I bought new. At 135 K it broke the crankshaft. The engine did not use any oil so I found a good crank shaft and just replaced the crank without disturbing the rods/heads or anything. I reused the dampener as I did not know they had an issue. I drove it two days and it broke the crank again. I thought the used crankshaft I put in may have been bad. So I went and ordered a new one from GM. The parts guy told me to get a new dampener as they had a service bulletin on the issue. I just installed the crank like I did the first one but did replace the dampener. That solved the problem.

I drove the truck for a few more years an then sold it. The fellow that bought it is still driving it and it has 300K on it. HE replaced the dampener at 200K and 300K.


Funny how things happen. Not more than a month after this we got a service bulletin from JD recommending that we replace the dampeners on high houred tractors for the same reason.

dej(jed)

Where are you located

(quoted from post at 09:10:43 02/12/13) dej(jed)

Where are you located

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Randy-I am located 30 miles north of Pgh.,Pa

I'm in need of a transmission for a 94 GMC 6.5 and was hoping you were a bit closer.
Mine has almost 400,000 on it and the transmission died, imagine that.

(quoted from post at 09:31:18 02/12/13)
I'm in need of a transmission for a 94 GMC 6.5 and was hoping you were a bit closer.
Mine has almost 400,000 on it and the transmission died, imagine that.

Click to expand...

The trany(automatic 4x4) was just rebuild 20K miles ago. Too bad we can't get it to you.

(quoted from post at 09:31:18 02/12/13)
I'm in need of a transmission for a 94 GMC 6.5 and was hoping you were a bit closer.
Mine has almost 400,000 on it and the transmission died, imagine that.

Click to expand...

The trany(automatic 4x4) was just rebuild 20K miles ago. Too bad we can't get it to you.

crankshaft is broken... not uncommon.

6.5 was a updated 6.2. Both made in Moraine, Ohio.

Hello dej(jed),

It is possible that the flex plate either broke or came off. Cheap fix if that all it is.
Take the cover off the botom and take a peak, you may luck out!

Guido.

Now I'm worried mine has 230 on it. Rebuilt the tranny and new brakes 10k ago. The body is in perfect condition that's why I decided to fix it.

What does a new damper cost? Consider it preventative maintenance. Keep the receipt as a plus if you ever sell it.

What does a new damper cost? Consider it preventative maintenance. Keep the receipt as a plus if you ever sell it.

Hi Yours is probably a sunny weather state truck and worth a fortune if it's got that many miles on and still runs great. GM might want to buy it back for a museum piece ! up here in Canada most of them have blown a few 6.5 motors and now the boxes/ cabs are rotting off. I got a 97 5.7 gas 228000 kms on it, the bodies bad and just waiting for the tranny to dump reverse, it's got the first signs showing now. was gonna upgrade to a duramax but was told buy a few different guys leave them alone after 200,000 kms they fall apart too.
Good luck with your truck and I hope you get another 100.000 out of it.
Regards Robert

Hi Robert I am from northeast ia. The truck has been driven every winter on treated roads. At least half the miles are trailer miles. I don't know why that has stood up like it has. One thing I do when I go to the car was is wax it. There is a few people would like to get hands on it. I do have duramax for my good truck. Someday I will put a ball in. If I knew how to post a picture I would.

I often haul between Clarksburg W. VA. & Nashville Tenn. if you could bring it to me & come & get it.

Hi
If it's as good as you say that's why guys are wanting it. It's the same round here 7.3 fords up to the change to 6 liter in 03 are making a couple thousand or more than 6.0's with less kms.
Guys are valuing the older more reliable trucks. it costs thousands to fix the newer diesels, and then they are still trouble waiting to happen.

I have said before in posts I got the 7.3 with 525.000 kms on over an 03 6.0 with 200.000 on it because of all the problems and repair costs. The 6.0 would bankrupt me in the end. Even our local ford repair shop I get on real good with told me buy the 7.3. that says a lot !
Regards Robert

Hi when I bought this truck I was looking for a 7.3. This one was coming ln on trade so bought it. Far as I'm concerned there is no nothing better than 7.3.