I've been looking for a diesel truck and I found two 6.5 TD's at a good price.



1994 Chevy 6.5 TD 5 speed with 159k miles - $5000



1996 GMC 6.5 TD Automatic with 242k miles - $5000



Between the two, which would be the better choice? What should I
look for when I test drive them? What's the deal with the
injection pumps and lift pumps? Are they really that unreliable?



Any input is appreciated. http://www.dieselplace.com/forum/smileys/smiley1.gif

the 6.5 is not unreliable when you gain a good appreciation for its operation. the lift pump may well be the most important peice of equipment on the truck. the lift pump is run off a relay that is oil pressure sensitive. this relay often fails, causing the lift pump to be non-operational. this puts added drag on the injection pump to be the only fuel supply. this high pressure pump will cause cavitation in the fuel if not properly primed, resulting in a loss of power. when the system is working properly, the truck runs strong. it will never be a duramax, but the trucks you are looking at cost less than the duramax option in the new trucks. the pmd or fsd is the other problem source on the 6.5. its an electronic module that controls fuel delivery. it fails due to heat. remotely mounted the pmd module on a heatsink/exchanger has cured this problem as well.


the things to watch our for on a 6.5 in my opinion are as follows. if the lift pump is operational, and it still misses under load, you have an injection pump problem more than likely. this is expense to fix, roughly 1000-1500 bucks. if the truck belches ungodly amounts of black smoke, there may be a turbo/wastegate issue that needs to be dealt with. this could potentially be expensive. generally, if the truck runs well, most problems can be dealt with. if the 6.5 you are looking at is a dog, then its best to steer well away from. these motors have been prone to cracked heads as well as countless other problems.





to sum things up, if it runs strong when you look at it, and there are no major tell tales immediately, it probably a safe buy...the small stuff you can troubleshoot yourself.





as a personal note, a truck with 242 and an automatic is not something i would be willing to buy, too many miles on all the running gear, the motor might take that, but the driveline will eventually fatigue. id look at the lower mileage strait drive truck

While the price looks attractive, for a little more you can buy a newer truck with more life in it, if it were my $$$ I'd look for 97 & up, 97 had major cooling mods, the earlier trucks are prone to overheat.

It's hard to say without hearing the rest of the trucks description and not knowing what had been recently rebuilt on them.

It's hard to say without hearing the rest of
the trucks description and not knowing what had been recently rebuilt
on them.



Both trucks are extended cab, 8' beds, and fully loaded. Looking
at the pics both are in good condition inside and out. No idea
about the maintenance history yet. I found them online and both
trucks are at the same dealership. Hopefully I can get up there
tomorrow and take a look at both of them in person.



Thanks for the tip on the 97 & up. I'll keep my eye out for one.

if the truck does blow black smoke, it really doesnt have to be that expensive. its only $90 for a turbomaster that will last the life of the truck.

if the truck does blow black smoke, it really doesnt have to be that expensive. its only $90 for a turbomaster that will last the life of the truck.


Or you can make your own for less than $10.

When first checking the truck out, start it up - does it start easily, or is there a Glow Plug circuit problem with white exhaust smoke for a little bit? Not all that bad to repair.


After it starts, check the upper radiator hose while cold. As the truck warms up, the upper hose SHOULD NOT get hard. If it does, it means that combustion gases are getting into the cooling system - RUN AWAY!


Remove the oil fill plug and check for blow-by. If it's bad - RUN AWAY!


Look at the rod for the Wastegate (connected to the Turbo). At idle it should be sucked in (towards the front of the truck) with so much force that you can't move it. If it's not, it might cost you upwards of $150 to repair the vacuum problems - Vacuum Pump, Wastegate Solinoid, Vacuum Lines, & Wastegate Actuator are the only parts involved (on an "F" code engine - no EGR).


Then just apply whatever you normally would check on a used vehicle - does it pull when you brake; are there any vibrations at speed; etc.

Texas TDI,<?:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><O:P></O:P>


Everyone has given you some really great advice, but I feel compelled to give you my .02 cents. Search through this forum, and you will see the horror story I have had with my '95 Burb. Fortunately, this story has a happy ending. With that in mind, spend a few extra bucks and find a rig with fewer than 100k if possible. Follow everyone’s advice here, and look for smoke, see if the motor skips while taking it on a test drive, check for excessive blow by, etc. Better yet bring along a mechanic who is familiar with these rigs. A general rule of thumb with these rigs is it starts and runs great when cold or hot, and then you are probably OK.<O:P></O:P>


Now for a couple words of caution. These are very short-lived diesels. Average life expectancy is 200k plus miles. So in other word the rig you were looking at with 242k is definitely in its twilight years. <O:P></O:P>


Secondly, if all else seems to be working well, check and double check for signs of head and/or head gasket issues. Is the truck consuming anti-freeze? Is the upper radiator hose hard after the truck warms up? Finally, do you see bubbles in the coolant tank when the rig is running, indicating pressure in the coolant system?





Also, check for excessive blow by coming from the oil dip-stick and/or steam coming from the dip stick tube. Both are bad signs, and may mean a new long block is in your very near future. Good luck!





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I would be inclined to go with the 1994 if it checks out. The 94's can be checked for DTC's with a paper clip, and it has much lower miles. I love the Auto in mine but you should get a bit better milage with the 5 speed. the 96 may or may not have the upgraded cooling as they added that mid year but with 83,000 miles more thats 4 years of driving at 20,000 per year.

1994 has Mechanical Injection?

If it's a dealer then they should know when the IP's where switched out and other typical service history.


With over 100,000 miles those trucks should have had at least one IP each if not two and the injectors serviced.


1994 chevy was first with an EFI turbo diesel.


My '94 has 314,000 on the orignal auto tranny, it's been worked to death towing and I'm antisipating a rebuild in the near future.Edited by: quantum mechanic

if the truck does blow black smoke, it really doesnt have to be that expensive. its only $90 for a turbomaster that will last the life of the truck.


Or you can make your own for less than $10. OK huisman, how much to make me one or just send me some good detailed pictures?

Take the VIN's to a GM dealer, they can run them and tell you any work done at dealership, date in service, commerical ownership or not, TSB work done, plus a ton of other stuff. Service department or Parts department should be able to do this. What city are the trucks located in? I have seen these motors go for many more mile than earlier indicated here but it requires TLC, don't over heat them, thats the big killer to these motors, As menitioned the 96.5 has better cooling BUT the older ones can be mod'd for bout 300.00 and be just as good in that department too.

I honestly only spent about $4.50 or so. I'll post a pic later just to show ya. http://www.dieselplace.com/forum/smileys/smiley2.gif

What city are the trucks located in?



Both are at a Dodge dealership in Greenville, TX. According to
CarFax the 94 is a one owner truck from Texas, the 96 is a two
owner. First owner was in Oklahoma, second owner was in TX.

http://www.dieselplace.com/forum/uploads/whuisman/2004-10-19_184751_PICT0016abc.JPG


http://www.dieselplace.com/forum/uploads/whuisman/2004-10-19_184813_PICT0018abc.JPG


I cut the wastegate plunger off its mounting bracket and reused the bracket. I bought a little piece of 1/4" threaded rod and a spring, and hooked it together with a little weld, a couple nuts, and a washer. Works like a charm.


Spent the money I saved on a boost gage.Edited by: w_huisman

I'll look in to this need to pick up another "bad" wastegate actutor to use