Can anyone explain the changes in the 6.5 from year to year?

[dka99burb]

Today: I am particularly looking at the differences between a 1996 C2500 pickup 6.5 engine and controls vs. my 1999 K2500 Suburban's. I think there was a cooling upgrade but did that effect anything else? Was the block or heads changed? Was there any other changes?

 

[ak diesel driver]

96 had a few mid year changes cooling being one of them. It can be either single stat or dual stat with the dual stat having the HO waterpump. Also they went to a 9 blade fan in 97 or 98. also a couple of options in blocks

 

[Missy Good Wench]

Cooling changes as mentioned.

The blocks saw some minor revisions in the oil squirter nozzle size (holes in the block smaller)
The outer main bolts on the center 3 went to a 10mm, from the 12mm

Pretty much the same game overall
There seemed to be a more noticeable issue with the later blocks to crack the number 8 cylinder than in previous years.

There may also have been some running changes in the injector pumps from 96 to 99

Both of these rigs have OBD2 controls.

Missy

 

[WarWagon]

Other than the above it will be small things like different seals in the oil filter adapter. Offhand without confirming it: Air filter being a K47 vs. a flat panel is a possibility. Controls are electronic and identical except for minor revisions. Turbo's may be slightly different unless 96 used a GM8.

 

[dka99burb]

Thanks for feedback. I just want to know if I pick up a parts vehicle what to look for.

 

[WarWagon]

You will want the same year. Makes things easier. There is still a production run change or two amounting to a lockwasher and radio wire. Never did figure out why the GMC had the extra radio single wire connector over the Chevy 1993. Transmissions have differences in some years. Wiring can be way different. The AC compressor swapped sides so the compressor, lines, belt tensioner, and alternator are all different depending on the model year they changed this. R-12 was an issue for the early years.

Interiors changed...

 

[Missy Good Wench]

R 12 was used up through the 93 models, then everything got 134A

Converting a 12 system to 134 is a bad plan. If you have an R 12 system, install envirosafe refrigerant into it and it will work reat and you will not have to update anything.

The 134 system is actually quite a bit different than a 12 in so far as the sizes o0f the evaporators inner core and the condenser too.

The pump uses different seals as the 134 is a totally different chemical and uses a different oil. The 134 will attack the seals in a 12 system and cause a whole handfull of problems that you simply dont need.

The sad part is that even if you do a proper conversion the system will never cool as good as the 12 system did originally.

Missy

 

[JMJNet]

Thanks for feedback. I just want to know if I pick up a parts vehicle what to look for.

If this is your question. When we buy parts, the part usually have part no. If the part is the same, then part no is the same, if not, then not.
If you ever in doubt, RockAuto have a very good part searching capability where you can match part no from different years.

Some exception is if you need to change the Lift Pump, you can use a 93 Lift Pump with slightly better flow rate and pressure rate.
The LP is plug and play to any model year.

Other distinguishing break is the OBD-I (94-95) and OBD-II (96+).
Although 96 is probably a little more weird since some part is the same as 95 while most are the same with the later year.

 

[dka99burb]

Cool... All very helpful. I was just considering picking up a 96 model truck cheap and driving till dead and keeping for parts.. Just due to the price.
I have decided I don't need another problem. Having enough fun figuring out my TCC issue on the burb.
Just a a thought though. There are a lot of great stickys on here. Maybe a listing the changes could be helpful when picking up worn out trucks for parts???
I don't know how difficult it would be for a pro?
Thanks Again.

 

[JMJNet]

Problem is the part that you need for the non-worn out truck may already be worn-out by the worn-out truck!!! LOL!!!

The 96's part is in worst condition than your 99 from the beginning.

The other unfortunate thing is that a lot of part now is china made, so that may not even be better than the original it replaced.

 

[dka99burb]

JMJNet,
I agree with everything you just said. Specially the China comment. I am on my 3rd clutch in less than 10k miles in my Dakota due to Chinese crap! How long is it going to take for the companies to wake up? I hope it is not too late!!