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Need 6.2L advice - might buy 1990 diesel Suburban

rich

1/2 ton status
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Apr 12, 2000
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Location
central NC
I have found a 1990 1/2-ton 4x4 Suburban with the 6.2L diesel, 700R4 auto, NP241. Only 99,000 miles. It is a Scottsdale, so vinyl seats, no carpet, no power windows or locks. But it does have A/C. Has been re-painted, looks good, no dents, no rust, interior is in perfect condition. The asking price is $3995.

I am really tempted to buy this rig for hauling stuff and towing my car trailer. (My current rig for this is a 1990 K5 with 200k miles, which is going to get the 1-ton axle, big tire treatment soon.) I know how to inspect this vehicle EXCEPT for the diesel engine. Are there common things I should look for when checking it out? I guess I should take it to a diesel mechanic too?

Thanks!
Richard

P.S. If I decide I need to just save my money instead of buying another rig, is anyone here who might be interested in this Sub? I can get you the contact number...
 
A 6.2L that has good compression will start very quickly - less than 2-3 sec. Look for smoke on startup and cold idle. Listen to how smoothly it runs, and make sure you don't hear any odd clacking aside from the ignition. Those are the tell tale signs of a diesel's health. Just sit and listen to it idle for about 5-10 minutes, then take it for a spin while watching for the same symptoms. After that, haggle or walk away. /forums/images/graemlins/thumb.gif
 
Thanks!!!

What do you guys think about the asking price of $4000? Kelley Blue Book and Edmunds say only around $2400 "private party" value for this vehicle in good condition. I think that's low. I priced my 1990 K5 on there and came up with about the same price, and I know that's low for my K5. Of course, if I could get this Sub for that cheap, I would! /forums/images/graemlins/smile.gif

Just found out that the trans was rebuilt at 88K. Guy said he had it done at AAMCO - got the best rebuild they would do, and it cost $2500??? It is a 4-speed auto, so 700R4, right?

I may test drive it tonite...

Thanks!
Richard
 
Yeah, it would be the 700R4- pretty much the only auto tranny around at that time, though certain rumors had it that certain models may have come with the 4L80e's.
 
1990 model year 1/2 tons would have the 700r4, 3/4 tons would have the TH400. 1991 was the first model year of the 4l80e. Which did get put into 1/2 tons with the 6.5TD and of course all 3/4 and 1 ton automatics
 
[ QUOTE ]
Thanks!!!

What do you guys think about the asking price of $4000? Kelley Blue Book and Edmunds say only around $2400 "private party" value for this vehicle in good condition. I think that's low. I priced my 1990 K5 on there and came up with about the same price, and I know that's low for my K5. Of course, if I could get this Sub for that cheap, I would! /forums/images/graemlins/smile.gif

Just found out that the trans was rebuilt at 88K. Guy said he had it done at AAMCO - got the best rebuild they would do, and it cost $2500??? It is a 4-speed auto, so 700R4, right?

I may test drive it tonite...

Thanks!
Richard

[/ QUOTE ]

Well it depends on your market but there is one right here, it's a diesel 1/2ton 86 4x4 for $1450 and it's a dealer so you know it's marked up.
It's all about offer and demand, I bought mine with a turbo but a tired engine, very clean silverado package 3/4ton for $1300 /forums/images/graemlins/whistling.gif

If you feel it's high priced keep looking, I waited 3 years to find mine.
/forums/images/graemlins/thumb.gif
 
Thanks for all the info! I bought it this morning for $3500.

Although it is not perfect, this Sub is very clean and I just couldn't pass it up. The 6.2 starts immediately when the key is turned (after glow plugs warm up, of course), and does not smoke at startup or idle. Rebuilt trans shifts firmly and feels good. My only real complaint is that it has 3.42 gears - I have some 33's I want to put on it, but I guess I'll stick with 31s for now. I need to add a trans cooler too.

One thing I have to change immediately - the harmonic balancer rubber is starting to look deformed. Will be replacing this week. Thanks for the info about this on this board - I never would have known to check that out. Also, it seems to run around or a little above 200 degrees on the highway. I'm going to drop a new 4-core radiator in place of the stock 3-core. And change the thermostat to 180-degree - I bet it is 195 stock, right?

Thanks again!
Richard
 
It should already have the largest 4 core rad available in our trucks...that's what comes stock.

check the clutch fan if it's running a little warm, they often stop working and most people don't notice.

Rene
 
From looking at it yesterday, I would SWEAR this thing has a 3-core, but I'll pull the fan shroud today and verify. I swapped a 4-core into my 1990 K5, so I can compare directly just to make sure. /forums/images/graemlins/smile.gif I'll let you know...

Good call on the clutch fan. You are right - I have had it go bad on other cars in the past, but I didn't even thing about it this time. I'll check that too today...

Thanks!
Richard
 
[ QUOTE ]
It should already have the largest 4 core rad available in our trucks...that's what comes stock.

[/ QUOTE ]

Actually the stock radiator on the light duty 6.2L is a 3 core. 4 core is on heavy dutys. The 3 cores are known for springing leaks because they flex so much...too thin to hold together well between the two large tanks.

I had a 3 core laying around that I was going to give to another board member who needed one badly to get back on the road. I took it to the rad shop to have it checked it out before I shipped it. They pumped it up with air and dunked it in the tank, and that think leaked from every possible joint! I ended up just tossing it. Not worth much to anyone anyway.

Upgrading from the 3 to a 4 core is a good move. FYI, you can also intsall a custom 5 row core, but that's probably overkill.

Casey
 
My old K5 had a 4 core stock. No HD cooling or towing package either.
 
I'm not entirely sure how GM decided to install which radiators into which trucks, but I do know that the standard 6.2L radiator in the 1/2 tons was 3 core. My '86 C/10 Suburban had a 3 core.

Casey
 
[ QUOTE ]
[ QUOTE ]
It should already have the largest 4 core rad available in our trucks...that's what comes stock.

[/ QUOTE ]

Actually the stock radiator on the light duty 6.2L is a 3 core. 4 core is on heavy dutys. The 3 cores are known for springing leaks because they flex so much...too thin to hold together well between the two large tanks.

I had a 3 core laying around that I was going to give to another board member who needed one badly to get back on the road. I took it to the rad shop to have it checked it out before I shipped it. They pumped it up with air and dunked it in the tank, and that think leaked from every possible joint! I ended up just tossing it. Not worth much to anyone anyway.

Upgrading from the 3 to a 4 core is a good move. FYI, you can also intsall a custom 5 row core, but that's probably overkill.

Casey

[/ QUOTE ]

Were the tanks good?
You could recore it to 4 core.
I never toss good tanks. /forums/images/graemlins/thumb.gif
 
I've only ever seen the 4 core diesel rads...and LMC only lists one rad for the diesels which is the big 4 core. /forums/images/graemlins/dunno.gif

Rene
 
[ QUOTE ]


Were the tanks good?
You could recore it to 4 core.
I never toss good tanks. /forums/images/graemlins/thumb.gif

[/ QUOTE ]

Yeah, I think the tanks were fine. Didn't think about that. I've already got a ton of stuff laying around, that I figured I'd never need a spare set of tanks. If my current radiator ever gives out, I figured I'd just install a 5 core at that time.

Casey
 
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