I've been looking at the 6.5td motor for a purchase for a truck because they are alot cheaper than dodge and ford. I am just wondering what are good years to look for as its been known that some of these engines can be problematic at times. Also are the trannies on these trucks relatively strong. when looking at these trucks what are some things to look out for.

1. compression
2. PMD sensor/relocate it
3. glow plugs, (old ones will mushroom and be a pain to get out)
4. turbo condition (they suck)
5. fuel pump, filters ect
6. cooling system, get a d-max fan/clutch and clean or replace the radiator and check the head gasket for leaks

as for the tranny, the 4L80E is more than tough enough to handle the most built up 6.5L.


my whole truck is for sale in the market place ;)

The big thing to look at is the pump mounted driver (PMD), also called a fuel solenoid driver (FSD) found on the side of the injection pump on '94+ trucks. Most of the 6.5's trouble came from this. If it has not been remote mounted outside the engine bay, i would strongly suggest doing that. If it's still on the pump, and not one of the lucky few, it will fail. The other thing is, if it shows signs of low compression/excessive blow-by, test those repectively.

Other, less minor things to look at are the vac system on '94+ trucks. The vac pump, lines, or solenoid fail, resulting in no vacuume to hold the wastegate closed to build boost. Most people opt to replace vac system with a turbomaster mechanical wg actuator. Upon start-up, check upper radiator hose for stiffness. If it's stiff on cold start up, pass on it. Also look for odd smoke.


4L80-E auto and NV4500 manual are great trannies. Some of the best available in that era.

Best years, I'd say '92-'95 with '92-'93 being the best of those. However, they all are about the same, just '95 and older are OBD-I and '92-'93 are mechanical injection.

For more complete 6.5TD buying guides, check the FAQ's.

Not a bad start; let's see if I can clarify some of it. Remember, anybody who comes on here and tells us they don't know what to look for isn't going to know what all the parts are called, either, so be clear and non-technical with responses.


1. compression

Yeah, but that's a pain in the butt to test... you need adapters, you have to pull all the glow plugs one at a time, ... if you aren't sure of what you're doing, checking compression is over your head. How about we start the truck, pull off the oil cap from the filler tube, and see if there is a lot of blow-by (evidenced by clouds of vapour coming out... a little is fine, LOTS isn't.)

2. PMD sensor/relocate it

Same thing. If you know what a PMD is, then it's easy to look for a relocate. However, not all relocates are equal, either... if the thing is running, good. If you need to change/relocate the PMD later, there's lots of info around here and lots of guys will help you do the job.

3. glow plugs, (old ones will mushroom and be a pain to get out)

Yeah, if they're ACDelco 9Gs or equivalent. If they've already been changed to 11gs, or if the truck is newer than 1996, it isn't an issue.

4. turbo condition (they suck)[/quote]

OK, not sure what to clarify for you here... remember, the guy is a rookie; what are you trying to tell him to look for? End shaft play, vane wear, oil pass-thru, wastegate operation...?

5. fuel pump, filters ect

Yeah.. look for service records, regular changes of fuel filter, turn on key and listen for lift pump 'purring' under driver's door (that's no guarantee it works, but it's better making noise than not making noise....)

6. cooling system, get a d-max fan/clutch and clean or replace the radiator and check the head gasket for leaks

Boy, I agree with the 'clean the rad' thing... you can tell if it's ever been pulled and cleaned just by looking at the bolts and hose clamps... if it hasn't been, you will probably get to do it.

As far as the DMax clutch/fan combo, let's wait on that until you tell us what year of truck you're looking at. The 99/2000 trucks had a 9-blade steel fan on them already, in most cases, and the factory FD clutch will likely still be good unless it's old or high miles.

Cooling system, 97+ had the dual Tstats factory, so again, let's see what he looks at before we start changing his parts.

As was mentioned, start the truck and squeeze the upper rad hose... if it stifens up, shut the truck off and leave... it has head gasket, or cracked head/block issues.


as for the tranny, the 4L80E is more than tough enough to handle the most built up 6.5L.

Yep, as long as it's been kept cool, fluid has been changed regularly, and hasn't been over-towed with big weights and the TCC unlocked.

Plus general abuse, like brakestands, geardrops and hard manual shifting under load, etc. Tough or not, trannies do get broke. Look for slippage, fluid that smells or tastes burnt, in fact make sure all the fluid levels are up.

Open up the coolant reservoir and check to make sure there isn't a film of oil lying on top of the coolant.

Crawl under the truck and look for leaks in the oil cooler lines, front and rear seal, tail of tranny. Check the front crankshaft balancer while you're under there for movement/clunking when you grab it and wiggle.

Every year has its own peculiarities... post up what you're looking at, and aside from these general guidelines, the guys around here can give you stuff to look for. Spend some time reading in the FAQ section, too... it's better to spend time now than money later, don't you think?

In my oppinion, as long as you know the beast, and educate yourself about the engine and truck, you'll have very few problems.

As far as which years being best, I don't see that being an issue as far as "what year truck to buy" all had perks and problems to watch for, OBD2 trucks had more power and better cooling, while the older trucks are better for "less shit to go wrong" such as piston cooling oil sprayer's in the 97+ blocks.

Now if you wanted to mix and match to build yourself the best of the best 6.5, that's a different story, some look for 94ish blocks, 97+ heads, cooling system, and GM-8 turbo.

Read through the FAQs and use the search button, and educate yourself as to what you think will better suit you.

I rebuilt the engine in my truck when I bought it (Engine was already out of truck before I bought it) did some internal upgrades, replaced injectors, glowplugs, filters, etc that was a year ago, and I've yet to have a problem engine wise. That's not bad for a 10 year old truck that I've only had to fix a U joint, replace the rear brakes and find an electrical gremlin on.

But I know a thing or two and this isn't my 1st 6.5 though ;)

1. compression
2. PMD sensor/relocate it
3. glow plugs, (old ones will mushroom and be a pain to get out)
4. turbo condition (they suck)
5. fuel pump, filters ect
6. cooling system, get a d-max fan/clutch and clean or replace the radiator and check the head gasket for leaks

as for the tranny, the 4L80E is more than tough enough to handle the most built up 6.5L.


my whole truck is for sale in the market place ;)


first off. the glow plugs won't swell unless they are 9G's. the 11G's won't swell they'll just burn out from extended glow times. the older SSdiesel instant heats would swell and burn out as well, the new ones seem to be fine. the 60G's and the Bosch duratherms are the best ones out there. they are self-regulating so they don't burn out from extended glow times.

second. theres nothing wrong with the GM-X series turbos. the wastegate system isn't the best set up. sure the bearing wear out in these turbos but they wear out in any turbo. remember they spin very fast. the best GM-X turbo is the GM-8.

third. for the cooling system the d-max fan isn't a absolute necessity unless your towing heavy. my truck has the stock fan from what i can tell and it cools just fine. the upgraded cooling system is a good idea however. the HO waterpump and the dual t-stat housing is a good upgrade. if the non-HO waterpump is on the truck with the single t-stat setup only an AC-delco or robert shaw thermostat can be used, and theres no exceptions on that.

fourth. the PMD is not a sensor. all the PMD does is take the signal from the ECM and boost it for the injection pump. the resistor in the PMD plug also fine tunes the fuel rate. resistors come in a #1 to #9 rating. Heath diesel uses the #7 resistor. heath's PMD relocation kit also comes with a 7 year warranty which is the best in the business.

someone needs more time in the stickies (http://www.dieselplace.com/forum/showthread.php?t=53309)