Anyone got a GM 6.5l? - PeachParts Mercedes-Benz Forum

Bajaman · #1 05-26-2009, 02:23 PM

I am looking at getting a 6.5 equipped Suburban for the family. I have heard a lot a bad things about this engine such as cracked blocks and injection pump failures. Does anyone here have a 6.5L who can give me an objective opinion and some things to look for before purchase? I'd appreciate it!!

eyeguy · #2 05-26-2009, 02:54 PM

I had one. I had a 96 Vandura. The block cracked. After which I did some research and found out all the "bad things" about the GM 6.5L diesel. I was never impressed with the power output or mileage.

I would look for something else.

#3 05-26-2009, 02:58 PM

My uncle had one was not impressed with it. He liked it for a while but then problems started. I belive his block cracked as well but can't remember for sure. Anyways was a bad engine. Would also suggest you find something else. What are your criteria for the new family car?

Skippy · #4 05-26-2009, 02:58 PM

I've never owned one, but we used a lot of them in the military. In the heavy HMMWV, the transmission was usually the first thing to go. After that problems with the body/chassis started. The engines were usually still running ok (slow but ok) after 30,000 miles or so. That's about the most miles I've seen on a HMMWV.

shotwell · #5 05-26-2009, 03:42 PM

Most of the military versions of the 6.5 I've looked at had no turbo. The Detroit 6.2 and 6.5 will run close to forever without the turbo. Problem is GM added the turbo system the the 6.5 for public consumption, to compete with the Cummins and then upcoming Power Stroke turbo trucks. That engine was never made to be turbocharged, thus the cracked blocks, broken crankshafts, etc.

The Duramax that replaced the 6.5 Detroit sadly has not been offered in the Suburban or Tahoe.

In short, I'd pass. Get a Ford product like an Excursion or Van. Those are solid machines.

equipmentjunkie · #6 05-26-2009, 05:57 PM

Be very careful. GM 6.5 engines can be money pits especially when they reach 100+K. Some people get lucky, some don't. I have found that the biggest fans of the 6.5 have a Chevy bowtie tatooed someplace on their body.

In short, I agree with Shotwell and the others.

FYI - Last week, I saw a '00 Excursion that had a 12-valve Cummins & NV4500 5-speed grafted into the engine bay. I could drive that.

cmbdiesel · #7 05-26-2009, 06:00 PM

Had a GMC Sierra 3500 with the 6.2 once......... never again.

Find an Excursion with the 7.3

blue-beater · #8 05-26-2009, 06:16 PM

New member, first post, been lurking for awhile due to purchase of a 190d recently ... before answering your question, a brief note about myself: I used to have a 1997 H1 with the 6.5 TD ... what I'm about to say is personal experience, not information from my brother's girlfriend's dad that heard it from a friend that read it on the internet. Got it? And yes, I can prove I used to own the truck if that's a question.

The biggest problem with the 6.5 TD is a cracked #8 cylinder. This cylinder is also in the rear of the engine so it gets the hottest with little cooling/airflow. This has little to do with the turbo and no, the military does not use this engine (TD) in their HMMWV, which explains why the ex-military mechanic posting isn't familiar. (BTW, civillian trannies are usually fine ... ex-jarhead here, we abused the HMMWVs ... military trucks use either the 6.2 or 6.5 non-turbo for maintenance ease).

The 6.5 TD CAN be a great engine but if it's been neglected (and not owned by and enthusiast) chances are, it'll fail; proper airflow is the most critical aspect. Another piece often to fail on these engines is the PMD ... you can remote mount these to assist but there's also debate on the effectiveness of remote mouting. Google PMD and 6.5 TD for more info.

If I were in your shoes I'd want to know mileage and maintenance history. Chances are if it hasn't failed in the first 40k miles and has had no major surgery, it'll be fine. I'd also read up on the items on this website, it's an enthusiast web site: http://www.heathdiesel.com. I believe you can also check the engine code to evaluate the recency of casting (which affects the #8) ... though I forget the website containing said information, google this too.

In summary, give the vehicle an honest evaluation and know what you're getting into ... in some circles the Suburban with a 6.5 TD is sought after, particularly 4x4.

Good luck,
Carl

PS My moniker "blue-beater" is for my project I may be posting about in the future.

Hit Man X · #9 05-26-2009, 08:00 PM

Most of the failures are with the 6.2, not the 6.5... tho' the 6.5 isn't a speed machine. Too bad GM never dropped the Duramax/Allison into the 2001+ 2500 Suburbans.

Early turbo 6.5 have all sorts of issues, the late ones... I guess 1996.5+ have all the updates taken care of too. Water pump, thermostats, radiator, injectors, etc.

Pal of mine has a 160k 6.5 TD in a 3500, it's a 1998. No issues aside from PM.

Do more research before the purchase. But as a few others pointed out, I'd be more inclined to scoop up an Excursion. If you get a 6L one, get the OASIS on it to see what is going on. Too many asshats today like to try to race an 8000lb truck just to see it run 14s in the 1/4 mile. I have a 6.4L F350 on order I should take delivery on early/mid June.

bigblockchev · #10 05-26-2009, 09:26 PM

You don't say what year or mileage Sub that you are looking at. This would help to narrow down the advice. I have a 95 3/4 ton 4x4 sub with 330Klms on it. The PO had the motor replaced about 40K ago The replacement motors with the updated blocks are much more reliable. The PMD can be remote mounted to virtually eliminate the IP failures. The 97s have improved water pumps and dual tstats which help with cooling issues, this can be retrofitted to any 6.5.The turbo wastegate control can be replaced with a simple adjustable spring device. There are a few fixes for the various problem areas which mostly solve the issues. Check the GM diesel forums at http://www.gm-diesel.com/diesel/vbull/forumdisplay.php?f=6
for discussions of the various issues. I like mine and there are almost no other similar vehicles around which have the seating or towing capacity. Cheers Dan

daw_two · #11 05-26-2009, 09:37 PM

if anyone needs a Cummins....I might know where there are one, two, or ten.

F18 · #12 05-26-2009, 09:49 PM

I must be one of the lucky ones after reading these posts.
I bought a 6.5td K-1500 Blazer new in 94 and ran the heck out of it!
I put on 373K miles with very little problem with the engine.
Had to replace the IP at about 150K with the new version IP that had more diesel resistant components than the original.
The rear diff wore out at 250K and I had it rebuilt.
The transfer case was replaced with a used one at over 300K.

When I sold it 3 years ago to a local contractor in town it looked almost new and still ran strong. He has run it up to about 425K and it is still going strong. I should add that the contractor had to replace the high torque starter motor at around 410K miles which I believe he said cost him $375.

I ordered it with the 3.42 rear end in it instead of the 3.78 because I did no towing and tried to stretch the MPG. Plenty of power! It got consistant
21 to 22 mpg on the highway which was not bad for that big heavy box of a vehicle. The comparable gas engine option (+7ltr) at the time with the same torque rating would have been lucky to get 14-16 mpg.

I miss that vehicle!

sixto · #13 05-26-2009, 11:10 PM

I'm by no means a GM fan but we have a 97 'burb 6.5 TD (no JimmyL, there's no TD badge on the barn doors

) with 164K miles and no problems. An Excursion might be a more reliable ride but they cost 3x what you can get a 'burb for. It wasn't cost vs benefit for us but afford vs can't afford.

To put my view in perspective, I had a 93 300SD and I continue to look for another one.

[edit] I forgot the plug for thedieselplace.com

Sixto
87 300D

#14 05-27-2009, 04:08 AM

Quote:

Originally Posted by shotwell

Most of the military versions of the 6.5 I've looked at had no turbo. The Detroit 6.2 and 6.5 will run close to forever without the turbo. Problem is GM added the turbo system the the 6.5 for public consumption, to compete with the Cummins and then upcoming Power Stroke turbo trucks. That engine was never made to be turbocharged, thus the cracked blocks, broken crankshafts, etc.

The 6.2 wasn't, but the 6.5 was designed from the start to have a turbo.

My grandparents had a 1995 Chevy extended cab 3500 with a 6.5TD. They used it to haul an 8,000lb gooseneck trailer all across the state to distribute the Sunday newspaper. The back seat wasn't the most comfortable place in the world but it never broke down in 3 years of doing that every week. They sold the truck when my grandma's health wouldn't let her go along on the trips anymore.

Bajaman · #15 05-27-2009, 07:41 AM

Well, this is pretty much what I expected to read. Like Sixto said, the Excursions are about 2-3x the money and that simply isn't an option. I've never had a car payment, and I'm not about to start now. The one I'm looking at today is a 95. It's got 160k, rebuilt tranny and IP last year. They are the second owner (9yrs) and used it to pull a large airstream (30ft?). If it hasn't failed yet, its likely one of the 'good' ones. They want $3500. This seems like a good deal to me. I can easily upgrade the cooling system to the newer format. I don't plan on doing much towing, there just isn't much else out there with a diesel that will hold 6+ people.