Hi all,

I've found a 1982 GMC Sierra Classic 1/2 ton 4x4 equipped with the 6.2L diesel and am considering buying it. I have just a couple questions that I'd like to get answered and I'm hoping this will be the place to do it.

First of all, the truck is in great shape in terms of body, drivetrain, chassis, suspension, steering, etc. I'm not a mechanic but know enough to tell when a truck has been taken care of. Put it this way, most of the original undercoating is in tact and there is NO RUST on the frame or any other part of the undercariage or body. The diesel is mated to the 700R4 transmission with a 205 transfer case (I think) and a GM 10 bolt rear diff. Not sure of the front diff but maybe a Dana44(any ideas)? The engine itself was replaced circa 1992 with a GM Goodwrench 6.2 liter crate engine and the transmission/t-case was rebuilt heavy duty at this time. This was done immediately prior to the current owner purchasing the truck from a friend so he doesn't have reciepts but I believe him for three reasons: 1) I spent over an hour with him going over/under every inch of the truck and he was brutally honest about every deficit the truck has (mostly cosmetic flaws), 2) the engine is obviously a Goodwrench replacement since the valve-covers are black and say GM Goodwrench, 3) the transmission shifts like its brand new (or better), I mean you can barely feel it shift and overdrive works well, no leaks, etc. The truck has ~175K miles miles with the replacement engine/trans in place for the last ~85K. The owner consistently adds a little ATF to his fuel (about 1/4 cup per 20 gal tankful) and he had complete records of service since he's owned it including: oil changes every 2500-3300 miles, transmission fluid drain/fill every ~50K miles, along with rebuilding the steering linkages (heavy duty tie rod with new ends, spindle seal kit, etc), and even records of regularly changing the diff fluid. It drove great albeit a bit of a dog.

So the problem is that I don't know much about diesels beyond a theoretical understanding of the cycle, let alone the 6.2 inparticular. Here are my questions:

1) What can you tell me about the replacement engine. Sounds like this is a significant upgrade compared to the pre-86 models from what I've read but why is this? This would explain the short life of the original 1982 engine. How do I find out which style engine this is (G, C, K, J)? Which is best and why?

2) One of the things wrong with it is that the fast idle solenoid doesn't work correctly. He corrects for this by gently touching the gas when starting the engine when cold. This seemed to work fine and the engine started easily but if this is my daily driver I'd want to fix it...could this be due to something more complex than the fast-idle switch itself. I've read about an inhibitor swich and glow plug controller. How expensive could this fix be assuming I do the work myself?

3) The owner claims 24 mpg unloaded at 60-62 mph. Is this realistic?

4) If I decided that I wanted to turbocharge it (Banks Sidewinder) would there be any detriment to durability/reliability/economy?

5) Anything else I should look for when I go back for a second look?

The best part is that it's only $1500 so I don't think I can loose, but I'm just a little scared since this would be my first diesel.

Thanks!

1. '92 Goodwrench, if it runs/starts good, not consuming oil, its a good one. Difference in the actual engine from different vin codes is basically nada, no real advantage in going with one over another, except a HD you won't have to worry about disabling the EGR, which over time does reduce the life expectancy and performance of the engine.


2. Fast idle solenoid makes 0 difference in startability, the solenoid simply engages to keep the L.I. position of the throttle lever a little higher to raise cold idle speed. Check for operation, it could simply be out of adjustment. Make sure he's not talking about the Cold Advance solenoid, which does help startability in cold weather.


3. 24 MPG, absolutely reasonable with his 700r4 and 3.42 gears, my old one regualarly logged 24-26.


4. Turbocharging, for one is expensive, and could possibly shorten life expectancy of the engine considerably, depending on its current condition and how the turbo job is done. Reliability, no change, Durability, fair chance of blowing head gaskets/cracking heads. Economy, I wouldn't expect to see much improvement unless you trailer a lot, you would probably see more improvement in driveability and economy.


5. 1500 sounds like a good price, if the truck is in good shape, its still and '82, 20+ year old trucks tend to break things that don't usually go out on newer trucks, expect to spend a little to get her up to snuff before you drive it everyday.

neutrino,


$1500 for that if in good shape sounds like a good deal, word of advise; if towing power is what you are after, bone stock 6.2 isn't the machine you need, it can be turned into a respectable one with some properly thought out work, and some smart junkyard diving it can be done for a relatively low price.