Chevy/GMC 6.2L and 6.5L Discussion of Chevy and GMC Trucks with 6.2L and 6.5L Diesel Engines

I want to buy this truck what should I watch out for?

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Old 10-08-2012, 12:51 PM
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Default I want to buy this truck what should I watch out for?

I found a 93 k3500 for a good deal <2k, I want to buy it. What, if anything should I look out for? this car isn't listed anywhere so don't even think about trying to ****** it from me.
here is some history,
owner knows nothing, got it as a lein because of work that didn't get payment, turned out the guy dropped it off and skipped town and the darn thing don't run. the intake manifold, and injection pump had been removed by a friend of his because he was going to "fix" it and just put them in the cab and left it as is and never got around to "fixing it"
I have a good motor that runs, from a 96' 2500, it has about 160k on it. If all else fails I can just pull the other one, and drop this one in. I plan to get all new seals/gaskets and bearings "main and rod" replaced/plastiguaged. new, better water pump, rad cap, thermostats, belt, tensioner, harmonic balancer, glow plugs, EGR delete, I'm wrapping the headers, and pipes to prevent excess heat transfer, anything else? basically I am using my motor as a good donor, I got everything wiring harness cpu, pmd pump, radiator, reservoir, air box.... everything. save the transmission and such, shoot, I even have the lift pump. The other truck "the one I want to buy" has about 200k on it, 4X4 ext cab. Am I missing anything? what all could go bad on this thing that I haven't listed? also is it a bad idea to use poly motor mounts or will that rattle the fillings out of my choppers? I plan to pull my 33ft 5th wheel with it across country, from cali to va.

---AutoMerged DoublePost---

I just remembered, the fellah, says he has no idea if it is mechanical or electronic, I would like to avoid electronic if at all possible, I thoght the 94's and up had the pmd, I read here and there and it seems no one has their facts straight on this one. I want to be sure so I don't end up having to buy a new/rebuilt 700+ dollar pump.
thanks

---AutoMerged DoublePost---

ok, so I called the guy back and talked to his "mechanic" friend, he knows squat, says the engine is toast, won't even turn over, supposed to be sending me the vin, nevermind, just got it
1GTHK39F3PE516470
I'll see what I can find out if it is a mech pump or electric

---AutoMerged DoublePost---

needs a 4911 mech pump, sourced it out and they are 700+ new"reman" new head and rotor ****, half the price of the truck.
 

Last edited by NintendoKD; 10-08-2012 at 12:51 PM. Reason: Automerged Doublepost
  #2  
Old 10-08-2012, 05:30 PM
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93 should be mechanical IP, also mech WG control. At one time Pensacol Fuel Injection had some reasonably priced reman IPs not sure of their inventory these days.

Several things could have it locked up including a stuck starter pinion or hydrolock, 96 block would work if worst case scenario is real, I would not wrap the headers, been my experience since Diesels don't get as hot as gassers header wrap tends to draw moisture.

Some thoughts on new buys from the Tech Ref Library at thetruckstop.us site from a long time 6.5 gear head Robyn aka Missy Good Wrench; since you are getting into a "semi-exposed" engine with mechanical some of it will not apply here:

Evaluating A Potential Addition To Your Stable of Diesel Rides by MGW

Here is how I evaluate one of these beasts.

First (After hood is open)
Check coolant level, oil level etc.
Look under the rig for signs of major leaks of oil coolant fuel etc.

Spin the engine without allowing the glow plugs to heat. The starter sound should be even with an even za za za za za za za za za sound

An uneven sound of za za za z za za za is an indicator of a low hole.

Once you have heard this sound you wull never forget it.

If you wonder what it sounds like, remove one glow plug from your diesel (H Front is easy )

Unhook the power to the OP or unplug the PMD and then spin the engine. aside from the swoosh of air from the glow plug you will right quick notice the different sound that things make.

OK

If the thing spins evenly, go for a glow cycle and see how it starts.

Good clean crisp start with no great amount of smoke is a good indicator that things are good in the injection system (compression too)

Some missing and white to bluish smoke that clears reasonably quick could indicate some glow plugs not working.

A longer time with missing and smoke can indicate that the injectors are tired and in need of replacement.

Once the engine has run for about 30 seconds there should not be any smoke at all.
Smoke at this point is indicative of issues with injectors or several other things.

A smooth running engine that still exhibits smoke at idle likely needs a set of injectors.

OK
Its running and seems smooth enough and has no smoke.

Look at the oil pressure.

45 or so is normal for a factory setup 6.2/6.5 and will drop off some when things warm up.

40 PSI runnin at speed and Idle at 20 or so.

While the beast is warming up feel the upper radiator hose, it should remain flacid (Soft and squishy) while the engine warms up.

A quick pressurizing of the cooling system followed by coolant puking over the overflow is an idicator of a blown head gasket, cracked head, cracked cylinder wall or ??? that allows compression into the cooling system.

OK
Engine warming up nicely and no issues. Take the rig for a romp and bring the engine to full operating temperature.

The top Radiator hose should have some pressure but not HARD and no coolant puking from the tank vent.

Engine should idle smooth and even with a nice even diesel cackle to it.

Take note of oil pressure, it should be steady and not below 20 PSI at Hot idle.

Shut down and let sit a couple minutes. Yank the dip stick and look at the oil, it will likely be black. Notice the level on the stick as well as the texture of the oil.

We are looking for signs of Glycol in the coolant.

A diesel will not always show a milky sludge if it is contaminated. The black soot will cover this up very good at times.

If we are dealing with a turboed engine, remove the air inlet to the turbo and inspect the inlet to the turbo.

Some oil pullover is normal as these engines get lots of miles on them. The turbo can even have a fair amount of sloppy residue just as long as its not dripping and totally juicey with oil.

While theair inlet is off, (Engine shut down) spin the turbo impeller, it should spin freely and not show signs of having been rubbing the housing.

Some slight radial play is normal but the shaft should not move in and out that you can feel much.

Look for signs of oil leakage from the turbo cartridge (center section) that is leaking down on the outside.

Some seepage is normal on any engine with a Buttload of miles.

Now lets look under the rig.

Any large drips that emanate from the bellhousing drain hole or around the filter area.

Again some seepage is very normal with miles and time.

Now

How is the tail pipe when your running down the road, smoking any at cruise speed. A little puff of black under full pedal is normal and depending on how the Pump is set up (DB2) or chipped (DS4) the smoke can be more or less.

The engine should run down the road with plenty of power (tain't no top fueler though)
The engine noise should be a nice even cackle that deminishes some with full throttle and gets a bit sharper under light throttle cruise.

With engine hot, shut down and let sit and heat soak for 15-20 minutes.
Try a restart without allowing the glow cycle to finish. The engine should start right up with very little cranking.

A long crank time hot can indicate a worn out injection pump (Was seen on some late DB2 pumps with high miles)


So now lets look at the accessories up top. Is there any undo noise, rattles or other obnoxious noises coming from the water pump, vacuum pump (later 6.5 stuff)

Take note of the belt drive, the isolator pulley (Serp drive systems)

This about takes care of as much as you can inspect without digging into the sucker.

If it passes muster this is about all you can do to tell what shape its in.

Now I will say this.
I have done the previously described protocols and drove a rig home only to have a head gasket blow a month later.

There is no way to tell absolutely what shape the thing is in.
To give an example

Bought a High mile Suburban off ebay.
The rig was in SanDiego Cal
Flew to Socal, met the seller, we look the rig over, he starts it up and its running fine.
(1995 2500 Burb 4x4)

Chating for few minutes and getting ready to hand him the check for the ballance owed.
All of a sudden the Burb starts missing, smoking like crazy (smells of diesel fuel and antifreeze) puking coolant out the overflow top hose hard as a rock.


Hmmmmm decided to blow a gasket right there. had this happend 20 minutes later I would have been out on one of SOCALS myriad freeways on my way back to Oregon.


OMG what a mess that would have been.

Cost me a flight to SanDiego then home again. Got all my Money back though for the deposit on the rig.

Not to try and scare but simply to point out that these things with a Buttload of miles can give up even though they seem fine.

Anything over 200K miles should be treated with the idea that it will need something in the way of work.

Hope this helps to scope out and purchase a used diesel.


best

MGW
 

Last edited by Turbine Doc; 10-08-2012 at 05:33 PM.
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  #3  
Old 10-09-2012, 12:29 AM
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A great big thank you is in order, This info is well received, and will be used to great effect.

---AutoMerged DoublePost---

Quote " I would not wrap the headers, been my experience since Diesels don't get as hot as gassers header wrap tends to draw moisture."
There is a reason for this, I'll explain. I want to mitigate as much heat as I can inside the engine bay as possible, I am doing an egr delete that would make any diesel enthusiast cream his pants, and I have a small wrx intercooler that I am mounting with custom hood louver to induce cool air. I don't plan to run any more than stock boost, but if that happens then it happens. I plan on using a very unique setup that is somewhat experimental, I want to keep it to myself for now, but it involves cooling and heating the fuel in stages, to allow for maximum vaporization and pressurization. I am also using a protective coating of high temp paint to reduce rust due to condensation on the pipes during cooling. I have been doing some reading on many various diesels, and how egr effects performance and economy, "hint hint" I think that there is a sweet spot that diesel needs to be at and that we haven't really been paying attention to. Everyone concentrates on how to maximize airflow, boost etc. but no one really looks at the fueling beyond just bigger better injectors/pump. To maximize ones fuel is the "kings chalice" so to speak. The diesel easily outperforms the gassers hands down due to simple volumetric and thermal efficiency, but we are still throwing away perfectly good unused thermal energy. I plan to use a fuel cooler, some special lines, and hot engine coolant returning to the radiator, as well as hot engine oil, with a combination of some very unusual/ functional plumbing. To fully maximize, I need to install all of this with the engine out, and stay away from things like computer driven modules. The pyrometer comes from aircraftspruce.com. I have very different ideas on how an IDI should run. To give an example, the 1.6 vw IDI's "yes I realize that it is laughably small and tiny" can run @ 7k + rpm's all day long, and at that point the only limitation is not air, or engine destruction, but fuel, the bosch fuel pumps just can't keep up. I am not planning to beat bill heath on the salt flats land speed records by any means, just want to see if I can get a little more economy and reliability.
 

Last edited by NintendoKD; 10-09-2012 at 12:29 AM. Reason: Automerged Doublepost
  #4  
Old 10-09-2012, 02:06 AM
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Originally Posted by NintendoKD
A great big thank you is in order, This info is well received, and will be used to great effect.

---AutoMerged DoublePost---

Quote " I would not wrap the headers, been my experience since Diesels don't get as hot as gassers header wrap tends to draw moisture."
There is a reason for this, I'll explain.

I want to mitigate as much heat as I can inside the engine bay as possible, I am doing an egr delete that would make any diesel enthusiast cream his pants, Just get a upper & lower F non EGR intake & be done with it, ceramic coat it and heat won't be an issue, you want your induction air cool so get a good cold air kit like Bill sells

and I have a small wrx intercooler that I am mounting with custom hood louver to induce cool air Don't get too small of an intercooler as it will be a choke point for you.

I don't plan to run any more than stock boost, but if that happens then it happens. I run the ATT turbo keeps boost well within design parameters of GM engine design does not stress engine, I'm capable of 100mph with mine with just 10 psi boost, my GM-8 turbo for same speed had to be pumping a hard 14psi, the ATTs bigger wheel and compressor give more mass flow which is what you want not so much psi

I plan on using a very unique setup that is somewhat experimental, I want to keep it to myself for now, but it involves cooling and heating the fuel in stages, to allow for maximum vaporization and pressurization.

I am also using a protective coating of high temp paint to reduce rust due to condensation on the pipes during cooling. Tried that myself with my 1st crossover (which is the 1st major heat loss point, painted the pipe-wrapped it, painted the wrap after installed thinking it was saturated/sealed via high temp paint and it still rotted but I wish you luck there, my unwrapped mandrel bent x over on it now has been there aluminized & rust free for 5 years now vs the 2 years the wrapped x over was on there

I have been doing some reading on many various diesels, and how egr effects performance and economy, "hint hint" I think that there is a sweet spot that diesel needs to be at and that we haven't really been paying attention to. possibly you have been at the wrong 6.5 Diesel site TTS is my normal haunt we discuss a LOT of alternatives for making power in the 6.5 performance section there

Everyone concentrates on how to maximize airflow, boost etc. but no one really looks at the fueling beyond just bigger better injectors/pump. You are not wrong there you need a reflash to get the PCM to request more fuel, timing adjust to make better use of the burn of the fuel, mods like my FTB Feed the Beast to keep voulme to the IP up at all load demands, take a look at precup sizes in the head some experimentation & gains happening in that area as well

To maximize ones fuel is the "kings chalice" so to speak. The diesel easily outperforms the gassers hands down due to simple volumetric and thermal efficiency, but we are still throwing away perfectly good unused thermal energy.

I plan to use a fuel cooler, some special lines, and hot engine coolant returning to the radiator, as well as hot engine oil, with a combination of some very unusual/ functional plumbing. To fully maximize, I need to install all of this with the engine out, and stay away from things like computer driven modules. The pyrometer comes from aircraftspruce.com. I have very different ideas on how an IDI should run. To give an example, the 1.6 vw IDI's "yes I realize that it is laughably small and tiny" can run @ 7k + rpm's all day long, and at that point the only limitation is not air, or engine destruction, but fuel, the bosch fuel pumps just can't keep up. I am not planning to beat bill heath on the salt flats land speed records by any means, just want to see if I can get a little more economy and reliability.
Good ideas, FYI it is rumored for economy best IAT is 150F or so the 6.5 handles 5000 rpm well, I'm in middle of project performance build going on 4 years in making now balanced blueprinted looking at 4000+ redline, I'm @ 3800 now, but you need stiffer springs for it to prevent valve float at the higher rpms, you might want to check into the performance area @ TTS site some prety good Diesel gearheads hanging out there with a LOT of 6.5 knowhow I've been dabbling with 6.5s since I bought my 1st one in 2000 when it was just a 36Kmi 2 y/o baby .

My current engine internally is bone stock quite capable of handling 25K# of towed loads, lots of external mods, built for towing with enhanced cooling, had an IC r(12x9x24") removed it when I went to ATT turbo wasn't necessary, have WMI just never installed it yet bought 3 years ago.

ATT netted me 3 mpg gain when I keep my foot out of it, one thing you did not mention in your quest for power/mpg is the high flow restriction of the GM series turbos at higher boost; and high in the GM turbo is 7+ psi in where the turbo efficiency really starts to drop off.

The GM turbo I've measured 50 psi backpresure in my old GM-8 @ 20 psi boost which also give you high EGT/high IAT/and higher coolant temps, ideally you want as close to 1:1 drive to compressor discharge pressure ain't gonna happen with a variable speed/load Diesel, you could try a VNT variant, some guys going the old Holset HX & HY turbos I happen to really like the ATT a good friend of mine owns the business and has the only virtually bolt on aftermarket turbo kit worth a flip.

Bill Heath runs twins on the LSR I'm a distant participant in the LSR team always seem to have to be out of town when he's running the thing, Bill & I chat often about this & that sometimes we wind up agreeing to disagree but hey what (2) gearheads don't do that all in the fun of "wrenching".
 

Last edited by Turbine Doc; 10-09-2012 at 02:21 AM.
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Old 10-10-2012, 12:26 AM
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I have talked to Bill on the phone, he seemed like he had better things to do, but entertained "some" questions. The thing he harped the most about, it seemed was the transmission and the locking torque converter. does this thing have that? Also, a longtime friend of mine was an oldschool mech that worked on hmmwv's all the way up till here recently. he gave me some very useful documents, and is going to help me with the pump, as his 25+ years of experience with these motors he has rebuilt from roosa master on up till stanadyne.
good stuff though, thanks a bunch

Kevin
 
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Old 10-12-2012, 12:38 AM
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So I guess the best 6.5 heads are the 96+ and the best blocks non-military are from 92,93, so I am thinking take the heads from my good motor, the bottom end from the bad one, and combine. Make it mechanical injection "db2", with ARP studs, and upgraded cooling, along with an intercooler "it is small, and routs inline with the turbo" and a fuel cooler, post tank, and a fuel water seperator. Mechanical wastegate control, and new seals, and bearings, plus an egr delete. I think that should cover all my bases. anything else I'm forgetting??? I heard something about a pin in the rear ends of these things being notoriously weak.
I already hav the "newer" motor paid 900 for it. the truck is about 1200, but I may be able to talk him down. new seals good, exhaust gaskets, I need a source for some, autozone is clueless, but I do already have a couple. new glow plugs check, I need the new bearings, but I need to plastiguage first. need to source the arp studs, I can get a db2 pump no prob, have a source for cheap. already have the new intercooler, my friend upgraded his wrx. I also have a fuel cooler, an all aluminum from a detroit diesel. I have aluminum stock to make the egr delete plate, and am going to delete the intake port for egr as well "weld the port on the intake mani shut" so I don't need to use the egr donut, and bolt a plate over the old egr hole. still need to get that "new" water pump with the dual thermostats. how do those work are they both standard, or do I use a low temp, or do I mix and match with those? I still have some nickel and dime stuff, but I'm looking at under 3500 total for the whole shebang, not bad, I think.

---AutoMerged DoublePost---

This setup is meant for haulin and daily driving. I guess I need the non dual t-stat, just the higher flow water pump combined with hoigging out the port to the gasket size, plus a bigger fan, since I do not like the price ol bill is asking for his big fan, I think I'll try to find it and outsource it. I was also thinking about going the route of adding an electric cooling fan, on the front side of the radiator, specifically for the A/C and heavy loads, I'll wire it up so that under A/C it will activate to cool the condenser, via a relay, and it will also be wired to a switch, for uphill towing use.
 

Last edited by NintendoKD; 10-12-2012 at 12:38 AM. Reason: Automerged Doublepost
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