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Pros & Cons of 6.5 Turbo Diesel?

This is a discussion on Pros & Cons of 6.5 Turbo Diesel? within the Duramax Forum forums, part of the General Discussion category; Im seriously looking into getting a 6.5l turbo diesel 1500 and i was wonder what some of the pros and ...

  1. #1
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    Pros & Cons of 6.5 Turbo Diesel?


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    Im seriously looking into getting a 6.5l turbo diesel 1500 and i was wonder what some of the pros and cons of this would be.

    I did some figureing on fuel prices over what I have now and what the diesel would be and I would actually spendless ondiesel than I would on gas. So theres 1 pro already lol.
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    Re: Pros & Cons of 6.5 Turbo Diesel?

    PROS:

    -Great Mileage (15-20MPG easily achievable)
    -Good solid torque
    -Readily Available parts and a burgeoning aftermarket (private businesses)
    -Will tow better than any 1/2 ton gas engine

    Cons:

    -Slow, so don't expect to be running with modded cummins,p-strokes or dmaxes.
    -PMD failure (for electrical injected engines 94+) which can be fixed in various ways
    -Takes lots of money to eclipse 250HP (at that point you should have nearly 450TQ anyway)
    -The more power you make, the more heat to deal with, so overheating and EGT's are something to worry about.

    Overall, a new fan clutch and a dmax fan should keep a good cooling system working optimally. Relocate the PMD to somewhere outside of the engine compartment on a heatsink. This along with a good set of glow plugs should give you a solid, reliable engine that can work harder than the half ton chassis can handle.


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    Re: Pros & Cons of 6.5 Turbo Diesel?

    Thanks koots, thats a pretty nice explination of things.

    How different are the diesel 1/2 tons from the gas 1/2 tons as far as chassis go? Or are they basically the same?
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    Re: Pros & Cons of 6.5 Turbo Diesel?

    They are the same, it's just the 1/2 ton diesel (S-code) isn't much far off from the HD 6.5TD (F-code). It's just the diesel is a strong engine for a half ton chassis even if the power numbers don't show how strong it is. My K5 Blazer w/6.2L diesel (non turbo)-700R4 and 3.42 gears with 31's used to get an easy 17-25MPG but now i've got a lift and 35's i get 15-20MPG on average. Even with the stock gears and 35's, the diesel has enough torque that it didn't cause a huge power loss. I felt more of a power loss going from 31's to 32's in my 98 K1500. That was with 3.73 gears and a 200HP/260TQ 4.3L.

    The half ton engines are gonna be lowest on power, but a quick F-code manifold swap (which deletes EGR as well) you should be close to f-code power.


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    Re: Pros & Cons of 6.5 Turbo Diesel?

    Definite pro as mentioned is the fuel. The extra money spent to get the diesel will pay itself off fairly quickly. If you want as trouble free as possible, go to a 1992/1993 with the DB2. If you want more power, it's easy to turn the pump up.

    If your looking for more power, and it is fairly easy to find, free flowing exhaust and boost and pyro gauges are rather important. pre-turbo max egt of 1250F. after that things start melting.

    Water injection really helped out with running my 6.5 cooler. That and opening up the hood so that air was being dumped onto the engine. But that is a fair bit of modding.

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    Re: Pros & Cons of 6.5 Turbo Diesel?

    Is your truck paid off though? Would strictly the better money savings of the better MPG's really save you that much after buying a 6.5 1/2 ton, selling your current truck, and then pouring more into the 6.5 to eliminate a few things to eliminate any doubts of reliability?

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    Re: Pros & Cons of 6.5 Turbo Diesel?

    yo sig, too big
    Hello, My name is Garrett.


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    Re: Pros & Cons of 6.5 Turbo Diesel?

    Quote Originally Posted by TheJavelin View Post
    Is your truck paid off though? Would strictly the better money savings of the better MPG's really save you that much after buying a 6.5 1/2 ton, selling your current truck, and then pouring more into the 6.5 to eliminate a few things to eliminate any doubts of reliability?
    Diesels don't have small maintenance items to cause small little issues like on a gas engine, so the parts may be well past their replacement point but the engine idles and runs as it should, but may be underpowered/underfueled. Not like a gas engine which would have required a cap/rotor, plugs, wires, 4 O2 sensors (the newer 6.5TD may have those though), 1 or 2 knock sensors, a fuel pump ($350-700). You could probably get away with not replacing any of those things either, but you'd be better off knowing the condition of these things before you consider a "new to you" vehicle purchase as a reliable vehicle. A 6.5TD would require an OPS, PMD, Injectors ($250-500), glow plugs ($80-120 for a quality set) and maybe a new or pro rebuilt IP (250-500 for DB2 and 500-750 for DS4).

    So what may seem like large purchases are not quite as large or unnecessary as it seems in perspective. The DB2 mechanical pump 6.5 and 6.2 diesels are even simpler and require less. Overall they will be cheaper, but aren't quite as precise in fuel metering as the DS4 but is only a handicap at extreme power levels. I doubt they will live as long of a life but i'm sure it's gonna last you a long while.


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    Re: Pros & Cons of 6.5 Turbo Diesel?

    Is this a 1500 with the 6.5TD already factory installed? Or you looking to swap.

    I'd highly advise against swapping in a 6.5TD in place of a gas engine.
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    Re: Pros & Cons of 6.5 Turbo Diesel?

    Yea my sig is a little big Ill get on fixing that soon.

    My truck has been paid for since the day I left the guys driveway. If I ever do find a good one for a decent price I could pretty much break even or better with what Id get for my current truck not to mention my wheels and tires would swap over nicely.

    I think it would be a pretty nice investment for myself not only for the mpg but for finally ending my desire of owning a turbo diesel lol.

    No Im not looking to do a 5.0 to 6.5l swap lol.

    Thanks for all of the replys
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    Re: Pros & Cons of 6.5 Turbo Diesel?

    good luck with that choice. :)

    on a side note, my buddy had a sweet little truck. 1995 ec/sb. five bolt 2wd, stock 6.5TD with 4L80 and 3.42's. we swapped an auburn posi into that truck and did a 3' straight pipe. the truck would get back 24-25MPG highway.

    lots of good pickup and decent towing. hard to find these trucks.

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    Re: Pros & Cons of 6.5 Turbo Diesel?

    Quote Originally Posted by 6.5 Detroit TD View Post
    good luck with that choice. :)

    on a side note, my buddy had a sweet little truck. 1995 ec/sb. five bolt 2wd, stock 6.5TD with 4L80 and 3.42's. we swapped an auburn posi into that truck and did a 3' straight pipe. the truck would get back 24-25MPG highway.

    lots of good pickup and decent towing. hard to find these trucks.
    I'd love to cram one of the 6.2's or 6.5TD w/early c-code precups into an S-10 (my brother has an ECSB 97 S10 2WD with no engine or front clip, which would be easy to mock up stuff in ) or a Camaro. Not for the speed or power, but for the economy. I think even the average 6.2 would be a fun engine for a smaller car. Even better with power added to it
    Last edited by Koots; 08-04-2011 at 01:29 AM.


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    Re: Pros & Cons of 6.5 Turbo Diesel?

    I was looking at a 40mpg jeep cherokee with a 4bt cummins bafore I got my chevy. Would have been nice if the owner took care of it.
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    Re: Pros & Cons of 6.5 Turbo Diesel?

    Working for the D.O.T. I would see a lot of these V8 GM diesels,the biggest thing was the glow plugs,seemed to be replacing those quite often,of course when You are working with a fleet that has about twenty of thse diesels everything seems to be regularly.glow plugs is easily enough replaced except for the right rear one or two on the newer model pickumups cause the turbo is in the way.Had to crawl under for those.
    Some of the engines,with well over 250,000 miles and I think there was one pump that needed rebuilding,I think that one was a sort of a factory fluke.
    Another thing tht needs checked on a regular basis is the waste gate linkage on the turboes,they seem to get rustickated on the swivel pins and will cease to work which makes um run quite gutelessely.Had one that the vacuum switch would fail,used two vacuum guages and got that one figured out.
    they did`nt seem to have a lot of power but alll of these engines were in one ton dualleys with a dump box and a headache rack which increased the wind resistance tremendousely.
    I too think that,in the 1500 series that these engines would be a real good puller and in a S10 a lot of fun.LOL
    There was a 1500 at the chevy dealer a while back but the money they wanted for that pickup seemed to be quite a lot and with using My 93 1500 with 240.000 miles,even with excellent body and interior,I just could not see giving what they were asking in the difference,of course i`m juz a po boy so anything difference would be toooooo much.LOL
    Last edited by MrMarty51; 08-04-2011 at 07:14 AM.

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    Re: Pros & Cons of 6.5 Turbo Diesel?

    The best glow plugs are the ACDelco 60G's or the Bosch Duratherm's or whatever they are called. They are self limiting so they won't overheat and swell or crack like others. Only issue is that they are slower to heat so it requires more glow plug activation time. I have mine hooked up to a push button starter switch and hold it for 7-10 seconds and she fires up within seconds almost everytime.


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    Re: Pros & Cons of 6.5 Turbo Diesel?

    Wow Ill have apretty nice thread to look back on if I ever do find the right truck.

    What would be your test drive checklist on a 6.5l if you were buying one today?
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    Re: Pros & Cons of 6.5 Turbo Diesel?

    Quote Originally Posted by Koots View Post
    The best glow plugs are the ACDelco 60G's or the Bosch Duratherm's or whatever they are called. They are self limiting so they won't overheat and swell or crack like others. Only issue is that they are slower to heat so it requires more glow plug activation time. I have mine hooked up to a push button starter switch and hold it for 7-10 seconds and she fires up within seconds almost everytime.
    The older glow plugs were I thinking around a six volt and the newer glow plugs are closer to twelve,I may be wrong in these nummerz so do correct Me if I am.
    The older glow plugs failed quicker due to the lower voltage rating and they would burn out.Very easily detectible wit the nekkid eye just upon a glance.They can also be checked with an ohm meter whilst still installed in the vehicle.I also tooo do`nt rememer the numbers but they should be listed in any good service manual,GM original manuals is the best.
    You are so correct.The A/C Delco Glow Plugs,Original equipment is always the best rather it be sparking plugs,heater motors or whatever.I have found here lately that the GM parts is about the same in pricing as what the parts house sells the aftermarket stuff for,I always specify to the GM parts people that this is for "Draper Repair" and they gives a somewhat of a discount so think of Yourself as a Shop at home and get um discount.

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    Re: Pros & Cons of 6.5 Turbo Diesel?

    Quote Originally Posted by Koots View Post
    I'd love to cram one of the 6.2's or 6.5TD w/early c-code precups into an S-10 (my brother has an ECSB 97 S10 2WD with no engine or front clip, which would be easy to mock up stuff in ) or a Camaro. Not for the speed or power, but for the economy. I think even the average 6.2 would be a fun engine for a smaller car. Even better with power added to it
    i have seen it done with a 6.5TD. would love to do it myself and yea, i would definitely use the 6.2 precups. a truck that small, you don't need a lot of power to make it move.

    also talked with a guy that stuffed a 6.5TD into a 4th gen camaro. really messes with your mind to hear it idling. :O

    also another local diesel performance shop in town is stuffing a benz five cylinder diesel making 300hp into a 95 s-10. going to be sick.

    there is a lot of stuff you can do. finding a truck like my buddy's thats stock with the 6.5 is hard. i know another guy who i apparently cant name on here who has the exact same truck. twin turbo setup built by garret, stock bottom end, over 250,000 miles on it. he can rev to 5500 and it put down 652rwhp and over 1000 rwtq on the dyno.

    to me the best part of the 6.5 is that they have a bad name in general, but if you know what to change, they can be bought for much cheaper then a cummins and still return a lot of good use.

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    Re: Pros & Cons of 6.5 Turbo Diesel?

    OP- if you find a 94 and up,

    check that the PMD has been moved off the IP and away from the engine.
    see how it starts. does it blow smoke on startup? a little bit of black smoke is fine. white/gray smoke usually equals IP problems. blue smoke, well im sure you know what that means.
    let it warm up and see if the coolant hose to the thermostat gets rock hard after it reachs operating temperature. if it does, possible head gasket job is needed.
    check the wastegate system to make sure the vacuum pump is working correctly. should take some effort to pull the wastegate against the running engine.

    92/92 is pretty much the same, except you don't have to worry about the PMD or the vacuum system. ;)

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    Re: Pros & Cons of 6.5 Turbo Diesel?

    bump.

    I guess I got the gist of owning a 6.5 a little. Anything else I should know or look for?
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