Need opinions on 6.5L GM TurboDiesel

[Ncostello]

Once again my volunteer fire department is on the prowl to find a decent used rescue truck. The latest find is a 1994 C-3500HD (15,000 GVWR) that has the 6. 5L TD with a 4L80E transmission. The truck has 58,000 miles (original miles). The cab, chassis, and body is everything we desire. However I'm not a huge fan of the 6. 5L Turbo Diesels.



I want to try and look at this without bias towards my favorite diesel truck... the Dodge Cummins. I'm usually the one the department looks to when deciding on a truck. But... I'm not too familiar with the 6. 5's and really cant say anything about them.



Can they provide years of troublefree service? Will we be looking at installing a new engine at 100K? We only average about 4 or 5 thousand miles a year. So it wont get driven into the ground. We have very high maintenance standards on our trucks so that won't be an issue. I just wanna feel good knowing I didn't get us into a big mechanical mess.



We spent our money on two pumpers (One new, one used) and this will be our last purchase for a while. The truck is $34,000 (also negotiable) which is very reasonable for what it is... . assuming the engine is good. I have no fears about the rest of the truck. Its just that once this amount is spent were done. We cant afford $100,000 for a new truck just like it.

 

[Ncostello]

This is the truck for sale.

 

[MD500E]

I don't have a lot of experience with the 6. 5 but I do have a 95 hummer with 6. 5 non turbo. The engine had to be replaced when it was only 6 years old with only 40,000 miles. It seems that the anti-freeze was never changed and the cylinder liners formed corrosion that eventually ate through the liners. I strongly recommend checking and changing the coolant.

Aside from that, If the truck is in good shape I would go for it. The 6. 5 isn't on the top of my list of favorite diesel engines, mostly because it does not take to being modified like the cummins, however as far as stock reliability, I would place it slightly ahead of the early powerstrokes. That is just my personal experience with friends as well as co-workers trucks.



PS: I work with a older gentlemen who drives an older 6. 2 with with over 240,000 miles on it. He is tired of fixing glow plugs so in the winter he starts it with a splash of gasoline in the intake!!!!

The motor runs away for a few seconds and it sounds like it goes to 6,000 RPM!!. I have no idea what keeps that thing running.

Good luck!



Kevin

 

[24vcummins]

That's a cool looking truck.



I had a 94 3500 w/ the 6. 5L turbo and auto trans. When I traded it in on my Dodge, it had 215,000 miles (had 190,000 when I bought it). The engine itself was fine, but I did have to replace the injector pump, transmission, and wiring under the dash. From what I understand, that was the 3rd injector pump that had been installed. Just my experience.



Best of luck to you and your fire department whatever you decide.

 

[CNichols]

The only thing that I dont like about having diesel emergency equip is that, everyone always jumps in them fires them up and most of the time is pull out of the station and its WOT. Even thou some emergency trucks have less miles on them I could see them having more ware. I have to say its a good looking truck.

 

[Ncostello]

Our guys like it cause it light years ahead as far as the body compartmentation goes. Our 1982 F-350 351W 4spd just has a utility bed body and its way, way over stuffed and over loaded. But it has served faithfully and never failed. Easy to maintain and will do 100MPH if needed. Buts she's startin to use a little oil...

 

[Will24]

You probably will never see a need to swap a complete engine, but head gaskets and injector pumps are definitely known problems with the 6. 5...

 

[Rebel_Horseman]

I can say you won't see triple digits in that truck. With good maintenance and no bombs the 6. 5 is a fairly reliable motor. My uncle had a '93 (first year for the turbo on the 6. 5) and he had about 250k on it when he sold it. The truck was abused mostly. For example, me and my cousin would take it and cruise, we spent the night in it (it ran all night while we slept on the way home from a rodeo in AL), they let it run all the time in the winter, and it regularly pulled a 30' stock trailer. the injector pump is the major weak point in the link, but aside from that it's pretty tough. Just don't buy a Dmax, unless maybe a new one. They are crap. . or maybe it was just the one i had. Anyway, if it's what ya'll want and are going to maintain it well I say go fer it!



Reb [><]

 

[MHubbard]

Go for the bottom price and buy it. Check out the 6. 2/6. 5 diesel web site. They will help you all they can. Also on that site they will tell you how to change over to a better injector pump then the one used. Because of the 6. 5 you will be able to get a good price. keep the filters up to date. zero all fluids when you get it. Make sure you check the glow plugs at least monthly. Use it.

 

[TPCDrafting]

Dad has a '94 1500 with the 6. 5. He has about 150k on it and likes it quite a bit. It's always losing a glow plug at least once a year. He also had a big problem with a computer module that mounts in between the heads go figure, it says right on the module to not get it hot!! He found somebody on the gm-diesel site that sells a relocation mount cheaper than the one GM sells. With a new module relocated so it won't get hot, it runs fine. The module was black and about the size of a deck of cards. It pulls better than my previous '91 chev 1500 with a 350, but it can't pull nearly like my CTD does. When I was a vol. FF we had 4-door GMC 4x4 dually's with 454's. They ran flawlessly other than we went through a set of brakes about every 3000 miles cuz we were up in the mountains and you know it was overloaded.

 

[DWest]

6.5

92 and 93 6. 5's had mechanical pumps and were very dependable motors. They are a light duty diesel with very high compression that run at 5 to 7lbs boost from the factory. They don't take well to high horepower increases as the lower ends are weeker and the two back cylinders tend to get the worst of it. The 94 and up suffer from the pump mounted driver, the little black box on the pump that runs the electronic function of the pump. They sit in the v of the motor under the intake mounted to the pump, theory being that the fuel running through the pump will cool them, bad idea. A remote mount for them is a quick fix and also makes it easier to relace if it does fail later. Most mechanics would replace the pump when only the PMD had failed. This motor also tends to run hot when pulling large loads as GM had undersized the radiator and the water pump. Easy to work on and simple. DW

 

[Fueler]

i had a 95 and it sucked. two weeks after i bought it the injection pump was replaced under a factory extended warrenty, then a week after i got it back the bottom end left the building. a new crate motor went in and i continued to have injection pump problems. i sold the new crate motor and dropped a GM 502 in its place.



i would rather have a 350 gasser than another 6. 5TD.



But i would rather have a CTD over just about anything else anyway

 

[Ncostello]

Thanks for all the good opinions. I'm sure I could fix anything it would ever need including injection pumps etc. But I guess I just hope I dont have to do that. When the trucks are down I'm the one who has to take days off of work to fix them... and the job I have now is harder to do that with than my old job. Our rescue can't wait till I can get to it... . which is how I do my own stuff . Guess I'm kinda trying to look out for the dept as well as myself.



Fortunately our newest pumper is large enough to handle the rescue duties also if need be. Back in the days prior to our new pumper, guys would donate their own pickups for use to haul rescue gear if our squad was down (which was rare). Thats kinda why we went with a large "rescue" body fire engine.



Anyway... I tried the 6. 2/6. 5 site and cant read the 6. 5 forums cause I'm not a member. It'll cost me 20 to do that. If we get the truck, sure I'll pay it. But to just read a little bit seems kinda high. How is anyone supposed to get new membership if you cant see what its all about?

 

[bmoeller]

Re: 6.5

Originally posted by DWest

92 and 93 6. 5's had mechanical pumps and were very dependable motors. They are a light duty diesel with very high compression that run at 5 to 7lbs boost from the factory. They don't take well to high horepower increases as the lower ends are weeker and the two back cylinders tend to get the worst of it. The 95 and up suffer from the pump mounted driver, the little black box on the pump that runs the electronic function of the pump. They sit in the v of the motor under the intake mounted to the pump, theory being that the fuel running through the pump will cool them, bad idea. A remote mount for them is a quick fix and also makes it easier to relace if it does fail later. Most mechanics would replace the pump when only the PMD had failed. This motor also tends to run hot when pulling large loads as GM had undersized the radiator and the water pump. Easy to work on and simple. DW

What he said.

 

[desert_thunder]

GM 6.5

Stay away from the GM 6. 5. They make GREAT boat anchors!!! But other than a boat anchor they are 100% worthless! They run hot and blow the head gaskets or destroy the block. They even have 2 thermostats. I blew 2 of them in less than 20,000 miles!



I purchased a Dodge prior to selling mine, and took a beating!.















97 DODGE

97, 2500, 4x4, SLT, 3. 54, 12v, X Cab, Bully Dog 60 HP injectors, TST # 4 plate, PDR 4k Gov. Sp, AFe Magnum Force, BD torque converter. BD valve body, BD ex brake, Mag-pan, Mag-diff cover, KDP Replaced, Banks Gauges (EGT, Boost, & Trans Temp), 4” Jardine exhaust, ATS manifold.

 

[Vaughn MacKenzie]

GM Diesel Website

Ncostello, there's a new GM diesel website that sprang up recently, probably because the Diesel Page started charging (I was a member 'til they booted me out for not paying).



Here: http://www.gm-diesel.com/diesel/vbull/index.php

I haven't checked into it yet so don't know how good it is.



Vaughn

 

[24VChev]

6.5

My truck (1994) was a 6. 5 for 100,000 miles and it never let me down... completely. It had about five injection pumps installed and two lift pumps, the two piece flywheel fell apart also. It would run hot going up hills towing 220+ and the egt (stock) were 1000* post turbo. The last 50,000 miles were "bombed" if I can use that term for the 6. 5. It's final demise was four seized pistons but that was my fault (drug induced).



Most of the injection pumps were changed because the dealer did not know how to diagnose it properly.



Stock the 6. 5 is alright but is no power house, thats what the Cummins is for! If I were going to buy it I would do:





1) Check the history at GM to see how many pumps have been installed

2) Check lift pump pressure.

3) Get the oil checked for antifreeze

4) Get a compression test

5) Have codes read



The 1994+ 6. 5 has pump mounted driver (PMD) that fails due to heat in the valley.



It also suffers from a poor cooling system.



If I bought it I would



1) Relocated the PMD to the fire wall or on top of the intake. I would just buy a new PMD and heat sink and leave the old one on the side of the pump, it is a real pain to remove.



Cost about $300. 00 usd



2) Update the cooling system to 1996+ parts which include 130GPM pump and dual thermostat. Get a cooling fan clutch from Kennedy Diesel that comes on at 200* instead of 220*



Cost about $400. 00 usd



3) Gages pyro, boost and fuel psi.



4) Ditch the side mount terminal batteries and get post mount.





The good thing about the 1994 is it does not have piston cooling jets as the 96 and up engines. The 1996+ blocks and cranks have very high failure rate due to cracking in the jet area. Make sure that the block is original.





GM released a 11 year or 111,000 mile (I think) wty on the injection pump and the electronics attached to the pump.



www.gm-diesel.com is a good site also

www.kennedydiesel.com sells the above stuff





Hope that helps. .







Malcolm

 

[DWest]

6.5

One problem with the GM diesel was that it was a half hearted effort by GM to add a diesel to its line of trucks. They only really wanted the light duty market where all the profit is and rather abandend the heavy duty sector. Thus any GM dealer lacked experience with diesel motors do to low volume. Sticking a turbo on the 6. 5 got them up front on the HP race but we all know thats not what moves trucks. So when the electronic diesels came out in 94 and the problems with the pump drivers showed up they didn't know what to look for and with a 100,000 mile warrenty in effect it was easy to just put on a new pump to fix any problem. So with a new unproven diesel and lack of expierience it was easy to choose the Dodge for my next truk, but GM has come far and my local GM dealer who always took care of me is now selling a ton of DM's and gaining a lot of respect for the diesel market. DW

 

[Ncostello]

Ya... I did alot of research on the internet so far. Looks like the PMD drivers is a big problem down there under the intake. And it sounds like you need some special tools to reset the timing once you rotate the pump to get the PMD off. The best solution was to leave the pump alone, get a wiring extension, and mount a new PMD elsewhere.



I did find out that the injection pump was replaced. Otherwise I'm told it runs fine... which of course tells me nothing. Its located in Midland Michigan... used to be owned by the Midland Fire Department. They do 3000 calls per year and most of them were medical/rescue related. They would probably know more than the dealer who sold them the new rescue. The dealer now has it as a trade in and he has it for sale. He's in Midland also.



There is no way in heck my department would let me install upgrades from later model years. They would not like spending $35,000 for something I'd have to invest another $1000 in plus the time involved in getting it into service. I'm not scared of the upgrades it would need... I just know they wouldn't like it too much.



I'd have a little trouble driving 7 hours then getting all that stuff done to check out the engine. I have no idea where I'd get all the stuff done in Midland in one day. But at least I know what I should have done if it does come down the pipe.

 

[78repowerwagon]

Re: GM 6.5

Originally posted by desert_thunder

Stay away from the GM 6. 5. They make GREAT boat anchors!!! But other than a boat anchor they are 100% worthless! They run hot and blow the head gaskets or destroy the block. They even have 2 thermostats. I blew 2 of them in less than 20,000 miles!



That reminds me I have a boat anchor for sale cheap!!PM me.



I know of 4 around here all have had the motor replaced.

3 went around 120k

the one holding down the concrete outside my shop has 180k and a busted bottom end.