Hello my name is Nick V, this is my first post to this form. I'm fixing up my parents 1998 Chevy 2500 6.5 long box regular cab, it has 156,000 miles. We bought this truck new. I currently have the box off and am painting the frame with por 15 I have redone most of the brake lines and calipers and replaced the trans at 120,000 miles and installed new glow plugs. What I was wounding is what on this engine I should replace that is prone to fail this is going to be my first ride and I rather fix issues when I have the fenders and grille for paint, rather than when they are on. I was thinking of replacing the harmonic balancer and maybe the injectors What are your thoughts off things that should be replaced on this 17 yr old truck. Also the tops of the windshield leaks is there any fixes for this? I will post some pics this weekend. It's amazing the memory's I have in this truck with my dad from my early childhood and I would like to preserve this thing as long as possible. They just don't make diesels the same and this has not been a nightmare like my moms 2002 duramax

 

If it's not broke don't fix it, you will want to do a PMD relocate and I may be wrong but I believe you have OPS mod from the factory and only use AC/DELCO when you do have to fix it, parts house brands suck in a 6.5 and would not be worth it if they where free.

Welcome

 

Thanks for your reply I already relocated the PMD do to it going bad previously. Also do you now how prone these engines are to cracked heads and cracked webs?

 

The 6.5s are prone to overheating which leads to cylinder block and cylinder heads cracking..

The 6.5TD doesnt take kindly to misuse, abuse, or neglect and I agree.. If it aint broke, dont fix it.. Replacement parts are NOT what they used to be.

If necessary for a peace of mind, pull and test the injectors to determine there condition before replacing them just for the hell of it.. If necessary, have them rebuilt if at all possible.
Although they reccommend replacing injectors every 100,000 miles, IMO as long as you avoid contaminated and/or alternative fuels, theres reports of 6.5 injectors easily doubling there "schelduled" or intended service life with no ill-effects.

Same with the Harmonic Balancers. Yes, there are TWO.. Remove the crank pulley and inspect both pcs thoroughly.. The primary HB is what most are familiar with, but the 6.5s lower crank pulley is a secondary HB..
Fliudamper primary HB are nice, and very expensive. For the cost of one Fluidamper HB, you could likely buy 5 OEM replacements.. IIRC they are no Fluidamper option or package deal that ncludes the 2ndary HB which based on my own experiece is the one that most frequently fails..
Unless you planning to bump up the power significantly and go WOT racing with it, I would stick with OEM and maybe consider the Fluidamper option when many years from now the OEM primary HB is found defective during any one of the schelduled inspections.

Windshield leaking or a defective cab running lamp or a torn/damaged door seal?
If its the windshield, you'll likely need to remove and reseal it for best results.


Beit paper or digital, purchase a set of factory authorized GMCorp Service Manauals for your application... helminc(dot)com may still be reproducing them..
DO NOT BOTHER BUYING HAYNES, CHILTON, or any other unauthorized publications pertaining to the 6.5.. I would go one step further and instruct you to avoid so much as reading them, full of inaccuracies. Ive determined those pubs are good for making quick misdiagnosis, emergency toilet paper and starting fires. Nothing more..


Good Luck

 

Thanks for the advice, The windshield is in deed leaking from the Tom seal is that a hard job to take out the windshield and reveal? Also I ordered paint and will begin painting the frame and underside of the bed and frame next week.

 

Heat is an issue so you can get a 180F thermostat from Napa etc. SSDiesel also carries them but for alot more. SSDiesels waterpump is a good upgrade that helps with the heat.

You can grab the military manual for the 6.2 and 6.5 its highly indepth with all the specs on the engine.

Some will say that the DB4 and all its electronics is a great fuel delivery system I would highly disagree. By converting to manual DB2 IP you will eliminate all the electrical issues as well as be able to run multi-fuel like the military. Also unless you set the fuel wrong you will see a huge mpg increase. Bobbie Martin wrote a great manual that is now free. The DB2 Conversion Guide | The Truck Stop

Personally if your running an auto transmission I would reccomend converting to a NV4500. A NV3500 would hold up and was put in the 1500 and the 2500 but the NV4500 is better in my opinion. An the cost of replacing a clutch vs rebuilding the 4l80e is huge. Buying a used NV4500 and all the other parts for the conversion was still $1000 less than a rebuilt 4l80e.

Also if you might look at rebuilt or new turbo.

The 6.5 is a great engine it just needs a few tweaks to make it the best it can be. Done right you can have good power and get 30mpg+ outta it.