Now that the truck has been reincarnated with the new head gaskets, I have been showering it with gifts. She does drive so much nicer now and gets better mileage, too!
I replaced the set of Interstate batteries the day before our temps fell to -7 degrees here, last week. When you own something so long you lose track of time. Turns out that the two batteries lasted 7-1/2 years and were only rated for 6 years. They definitely make a difference on a diesel, where you have to have two batteries due to the 20 to 1 compression ratio. she sure spins over fast and starts on the first crank, now.
I also upgraded to the 1997-2000 "K47" High Capacity air box which uses the giant tubular filter instead of the flat panel model air box on the earlier models. Since a diesel operates on an unmetered air supply, it needs all the air possible at all times. Only the fuel is metered. They also require cold air from the front end of the truck via the inner fender ducting, and no hot under-hood air.
Here is the original, restrictive, flat panel filter box found on the 1993-96 6.5 diesels:
I was able to find the correct K47 air box set up from a 1998 6.5 Diesel GMC 3500 dump truck in a local junkyard. The diesel K47 set up is a unique component and nothing interchanges with air boxes on the gas-engine trucks of that era. It cost me $40 which was a bargain since the air boxes normally trade in the $150 range.
Here is what it looks like:
The crazy looking 2" tubing is just a noise reduction tube.
The big problem I ran into was that the unique piece of ABS plastic tubing that inserts into the air filter and mounts into the turbo rubber bellows was mangled beyond repair. It seems that whoever bought the turbo off that 1998 dump truck removed it with an axe instead of simply unscrewing the hose clamp that retained it. [img]<<GRAEMLIN_URL>>/mad.gif[/img]
I did have to order the air box mounting bracket from GM. That piece cost me around $60. It is a rather unique piece and has two studs attached to it that lock into the two grommets that are in the bottom of the air box base (which BTW are discontinued from GM so I found two perfect replacement grommets for $2 in the hardware aisle at Lowes).
Got the air box installed today. I had to improvise a bit and it actually worked out better than finding the correct GM duct piece. I went to the plumping aisle at my local Lowes and bought a 90 degree, 3" inner diameter, PVC elbow for $4. One end fit perfectly in the new air filter element. As for the turbo bellows end, in order to keep the positive battery cable bolt from rubbing on the "new" duct, I mounted one end of the elbow in a vice and used my heat gun to heat up. I was able to then squeeze one end into an oval to match the bellows and also clear the battery bolt. I imagine it also flows a helluva lot better than the original piece that necks down from a round 3" intake to an oval 2" wide exit.
Here is the final result:
