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Discussion Starter #1
I've been lurking for a few weeks now and have learned a lot. I'm now at the point where I want to take the plunge, so to speak, into diesel.

I'm looking at a '90 suburban with 164k miles. It has a perfectly straight body with absolutely no rust. It is a state owned vehicle, I've seen the maintenance records and no major problems have surfaced. Until it reached 105K, only scheduled maintenance was performed. Since that time it got a new EGR valve (2000), new pinion bearings (2001), an ABS brake module (2002), rear axle seals and crankshaft pulley (2003), lift pump (2004) and most recently a glow plug controller (2005). Considering the age and mileage wouldn't these be considered pretty much maintenance items. From what I've read here, it's probably at the point of needing a new/rebuilt IP and new injectors soon.

Should I consider this thing a ticking time bomb or to be one of the good ones? Comments please. Thanks

Peyton
 

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2 major things that might pop up before too long. 1 is the injection pump. you can get a rebuilt unit on ebay for cheap and not too difficult to replace. 2. the auto tranny, depending on if the truck is a 1/2 ton or a 3/4 ton. the 1/2 ton will have the 700r4 (4 speed OD). the 3/4 ton will have the th400. th400 is much stronger/more reliable than the 700r4, but depends mostly on how the vehicle was used. see if you can test drive the suburban. if you notice any tranny slippage, expect to rebuild/replace it before too long. look at the tranny fluid. if its dark or smells burnt, again expect a rebuild before too long.

glow plugs might need replacement (standard wear item, pretty much like replacing spark plugs in a gasser), check the rear window motor if the suburban has the tailgate style rear door. if it has barn doors, nothing to worry about. the rear fan (up on the ceiling at the very back of the cab) is a very common problem, but again its not hard to replace. if you turn the rear fan on, and it makes alot of noise (you can hear it up in the drivers seat) then replacement is needed, unless you dont care about rear air.

these are very solid, simple, and reliable vehicles. not to mention extremely safe in a wreck (i had an 89 suburban in high school, VERY solid vehicles). if you need to replace the tranny you could drop in a manual without much trouble at all. 164k miles is not much on a diesel, or an old suburban for that matter. my 89 with a 350 gasser had 330k miles on it when i sold it, still ran great. many members on this board have well over 200k miles on their 6.2L vehicles, regular maintainance is the key. overall by the sounds of it this suburban should be a reliable vehicle.
 

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peyton;1565219; said:
I've been lurking for a few weeks now and have learned a lot. I'm now at the point where I want to take the plunge, so to speak, into diesel.

I'm looking at a '90 suburban with 164k miles. It has a perfectly straight body with absolutely no rust. It is a state owned vehicle, I've seen the maintenance records and no major problems have surfaced. Until it reached 105K, only scheduled maintenance was performed. Since that time it got a new EGR valve (2000), new pinion bearings (2001), an ABS brake module (2002), rear axle seals and crankshaft pulley (2003), lift pump (2004) and most recently a glow plug controller (2005). Considering the age and mileage wouldn't these be considered pretty much maintenance items. From what I've read here, it's probably at the point of needing a new/rebuilt IP and new injectors soon.

Should I consider this thing a ticking time bomb or to be one of the good ones? Comments please. Thanks

Peyton
It depends on how much you like it, how much you are paying for it, and how much work you can do yourself. At that mileage level, with no previous major repairs - you can expect to be rebuilding the trans. soon, it certainly ought to have new injection nozzles (they are beyond their normal useful life), along with routine items like brakes, front-end parts, etc. The injection pump is probably getting worn in the timing-advance - but it's not the sort of thing that's going to fail and leave you dead on the road.

I just bought a 91 V10 4WD 6.2 diesel Suburban from a local school. It has some rust - but not much. It has 149,000 miles, an it too has had no major repairs except rear pinion bearings, brakes, and front ball-joints. I paid $225 for it on sealed bid. I don't plan on doing any long trips with it until I change the injectors, pull the pan on the 700R4 trans. and check for signs of wears, put a good exhaust system on it, etc. I also am going to check the fuel-timing advance on the injection pump, and if sluggish - I'll probably pull the pump off and repair it.
 

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jdemaris;1565305; said:
I just bought a 91 V10 4WD 6.2 diesel Suburban from a local school. It has some rust - but not much. It has 149,000 miles, an it too has had no major repairs except rear pinion bearings, brakes, and front ball-joints. I paid $225 for it on sealed bid.
do you have any idea how cheap you can get older vehicles up where you are compared to here in texas? that same suburban that you just bought, with minor rust, would run about 2-3k, privatly sold. before i bought this 81 gmc pickup i looked at a few old suburbans, i found 2 in my area.
1. 83 chevy suburban with a 350 1/2 ton. interior was torn to shreds, roof was rusted, rebuilt tranny, and good running motor. price-2200.
2. 89 chevy suburban with 350, 1/2 ton 4x4. tranny rebuilt, good paint, good interior (a few minor stains), 3rd row seat missing, no mechanical problems. price-4500 was the lowest they would go, it sold.

your very lucky jdemaris on the price of used vehicles. i know you have rust to worry about, but i cant even get a wrecked vehicle at a junk yard for that price out here.
 

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Discussion Starter #5
jdemaris;1565305; said:
It depends on how much you like it, how much you are paying for it, and how much work you can do yourself. At that mileage level, with no previous major repairs - you can expect to be rebuilding the trans. soon, it certainly ought to have new injection nozzles (they are beyond their normal useful life), along with routine items like brakes, front-end parts, etc. The injection pump is probably getting worn in the timing-advance - but it's not the sort of thing that's going to fail and leave you dead on the road.

I just bought a 91 V10 4WD 6.2 diesel Suburban from a local school. It has some rust - but not much. It has 149,000 miles, an it too has had no major repairs except rear pinion bearings, brakes, and front ball-joints. I paid $225 for it on sealed bid. I don't plan on doing any long trips with it until I change the injectors, pull the pan on the 700R4 trans. and check for signs of wears, put a good exhaust system on it, etc. I also am going to check the fuel-timing advance on the injection pump, and if sluggish - I'll probably pull the pump off and repair it.
We certainly don't get them at that price around here. I assume you are in snow country where 4wd diesels of this vintage are much more common.

I didn't mention it in the first post but this is a 1/2 ton 2WD vehicle. According to the maintenance mgr, the complete brake system was rebuilt in oct of 2003. I'll be doing as much of the work as possible. I've worked on cars for much of my life but never on a diesel. How difficult is repairing an IP? Does it require special tools? Thanks

Peyton
 

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Repairing an IP isn't really a DIY job unless you have a lot of diesel experience. Most Diesel mechanics don't even do it themselves. Almost all of that kind of work is sent out to specialty injection shops.
 

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red suburban;1565333; said:
do you have any idea how cheap you can get older vehicles up where you are compared to here in texas?
your very lucky jdemaris on the price of used vehicles. i know you have rust to worry about, but i cant even get a wrecked vehicle at a junk yard for that price out here.
Funny thing is, the "grass is always greener on the other side of the fence." I often see vehicles I'd love to buy in your area - but cannot afford the trucking.

In regard to pricing around here - there's a big difference between private sales and "sealed bids" and auction vehicles. It would not be unusual for a private seller with a 91 diesel Suburban 4WD - if in nice shape to be asking a couple of thousand dollars. On the other hand, if it sat at the repair shop with a huge estimate to fix it, it might be bought for next to nothing. There's guy down the road from me right now with a rust-free 1994 Ford F250 7.3 turbodiesel 4WD ex. cab and 331,000 miles on it. He's asking $6000 but will probably have trouble even getting $4000. I bought a similar truck last year for $3300 and much less miles. 1994 ex-cab, 4WD, 7.3 turbo diesel, 8' bed, cap, and gooseneck hitch. It is a spotless Colorado truck. The guy was here visiting his parents - but an emergency came up and he had to fly home, quick. Later, he asked his parents to sell the truck - and I got lucky and bought it.
I usually only buy from auctions or "sealed bids" from various governments. The bid-thing can sometimes get you ticked off since there is no incremental bidding. Last year, a town nearby had a real nice K5 diesel Blazer with 60K miles on it. I put in a bid of $1200 and got it. But . . . I found out the next lowest bid from mine, was $300. I had no way of knowing, but if I had bid $400 - I would of gotten it.
 

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peyton;1565354; said:
How difficult is repairing an IP? Does it require special tools? Thanks
Peyton
When I first went to work as a diesel mechanic, many repair shops did their own injection pump work. First shop I worked at, we did our alternators, generators, magnetos, starters, cylinderheads, injection pumps, piston rebuilding, rod resizing, flywheel resurfacing, etc. Very little was sent out. We had our own injection pump test stand but rarely had to use it.

Today, things have really changed. Kind of like the medical profession. Go to a general MD, and if he thinks you've got something serious - he sends you "out" to a specialist.

With the Stanadyne injection pump - it's not very complicated and parts are easy to get. But - a few problems.
First of all, Stanadyne keeps most repair info secret - and won't release it to you unless you are a registered Stanadyne repair-guy. There are other sources, though.
Second problem - is the pump as it sits in a 6.2. When these type pumps are used in industrial equipment, it's pretty easy to make fuel-advance timing observations and adjustments - on the pump as the engine is running. Not so with the 6.2 since the pump is buried in the middle of the engine. To avoid a lot of trial and error, you really benefit from having a pump test stand to mount the pump on, run it, and test it, before sticking it back onto a 6.2. With many pump shops - a large part of the cost of the pump is the stand setup work.

Many pumps that need work only need $50 - $75 in parts to fix, and a pump can be completely taken apart, checked over, and put back together in two hours.
 

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Discussion Starter #9
red suburban;1565297; said:
2 major things that might pop up before too long. 1 is the injection pump. you can get a rebuilt unit on ebay for cheap and not too difficult to replace. 2. the auto tranny, depending on if the truck is a 1/2 ton or a 3/4 ton. the 1/2 ton will have the 700r4 (4 speed OD). the 3/4 ton will have the th400. th400 is much stronger/more reliable than the 700r4, but depends mostly on how the vehicle was used. see if you can test drive the suburban. if you notice any tranny slippage, expect to rebuild/replace it before too long. look at the tranny fluid. if its dark or smells burnt, again expect a rebuild before too long.

glow plugs might need replacement (standard wear item, pretty much like replacing spark plugs in a gasser), check the rear window motor if the suburban has the tailgate style rear door. if it has barn doors, nothing to worry about. the rear fan (up on the ceiling at the very back of the cab) is a very common problem, but again its not hard to replace. if you turn the rear fan on, and it makes alot of noise (you can hear it up in the drivers seat) then replacement is needed, unless you dont care about rear air.

these are very solid, simple, and reliable vehicles. not to mention extremely safe in a wreck (i had an 89 suburban in high school, VERY solid vehicles). if you need to replace the tranny you could drop in a manual without much trouble at all. 164k miles is not much on a diesel, or an old suburban for that matter. my 89 with a 350 gasser had 330k miles on it when i sold it, still ran great. many members on this board have well over 200k miles on their 6.2L vehicles, regular maintainance is the key. overall by the sounds of it this suburban should be a reliable vehicle.
It is a 1/2 ton with 2WD and has the overdrive tranny. I got the feeling that it was mostly a supervisory vehicle so I doubt if it was used much for towing anything ... I'll check on that. I got to drive it around the parking lot but since it is no longer licensed they didn't want me to take it out on the road. I didn't notice any slippage in that short test.

The ac system was rebuilt (new compressor, etc) and converted to 134a in 2001. The rear works and is quiet.

I don't plan to do much, if any, towing. Just trips of 400 to 1500 miles on fairly level ground. I hope the 6.2 will pull a decent speed in OD on the freeway.

Peyton
 

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peyton;1565391; said:
I hope the 6.2 will pull a decent speed in OD on the freeway.
Peyton
If it has the 3.42 axle ratio and the standard tires it will cruise at 75 MPH no problem. If it has the 3.08 axle ratio, it will be bit underpowered on uphill highway grades and shift in an out of OD a bit - but otherwise will be okay.

My 87 4WD 3/4 ton 6.2 Suburban with 3.73 gears, and no overdrive cruised nicely at 65 MPH but at 75 MPH it sounded like it was going to blow up. It eventually did, but it made it to 520,000 miles.
 

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Discussion Starter #11
jdemaris;1565366; said:
In regard to pricing around here - there's a big difference between private sales and "sealed bids" and auction vehicles. It would not be unusual for a private seller with a 91 diesel Suburban 4WD - if in nice shape to be asking a couple of thousand dollars. On the other hand, if it sat at the repair shop with a huge estimate to fix it, it might be bought for next to nothing.
.....snip......
I usually only buy from auctions or "sealed bids" from various governments. The bid-thing can sometimes get you ticked off since there is no incremental bidding. Last year, a town nearby had a real nice K5 diesel Blazer with 60K miles on it. I put in a bid of $1200 and got it. But . . . I found out the next lowest bid from mine, was $300. I had no way of knowing, but if I had bid $400 - I would of gotten it.
Even at auction here prices are much higher than you have. I haven't sat in on enough auctions yet to say whether it's only 1 or 2 buyers/dealers that drive the prices up or whether there is actually a fair amount of interest.

There don't seem to be that many diesel blazers/suburbans for sale privately here either. Or maybe I just don't know where to look.

And yeah, those sealed bid sales can really get your knickers in a twist.

Peyton
 

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there is almost no older diesels in my area either.

good about the ac and rear air, very good that it wasnt the tow vehicle as well.

how easily did the truck fire up? i know here in texas it doesnt get that cold (i'm originally from houston, harris county). water in the fuel can be a problem with the amount of humidity in houston, but if you dont let fuel sit in the tank for long periods of time (months) then it shouldnt be a problem. did you look at the rear doors/tailgate? if it had barn doors you dont have anything to worry about back there, but if it had a tailgate did you mess around with the rear window?

from what you've posted here i'd say go for it. staying at 70mph on the houston freeway wont be a problem, you dont live anywhere even near mountains so thats no problem.
 

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Discussion Starter #13
jdemaris;1565387; said:
When I first went to work as a diesel mechanic, many repair shops did their own injection pump work. First shop I worked at, we did our alternators, generators, magnetos, starters, cylinderheads, injection pumps, piston rebuilding, rod resizing, flywheel resurfacing, etc. Very little was sent out. We had our own injection pump test stand but rarely had to use it.

Today, things have really changed. Kind of like the medical profession. Go to a general MD, and if he thinks you've got something serious - he sends you "out" to a specialist.

With the Stanadyne injection pump - it's not very complicated and parts are easy to get. But - a few problems.
First of all, Stanadyne keeps most repair info secret - and won't release it to you unless you are a registered Stanadyne repair-guy. There are other sources, though.
Second problem - is the pump as it sits in a 6.2. When these type pumps are used in industrial equipment, it's pretty easy to make fuel-advance timing observations and adjustments - on the pump as the engine is running. Not so with the 6.2 since the pump is buried in the middle of the engine. To avoid a lot of trial and error, you really benefit from having a pump test stand to mount the pump on, run it, and test it, before sticking it back onto a 6.2. With many pump shops - a large part of the cost of the pump is the stand setup work.

Many pumps that need work only need $50 - $75 in parts to fix, and a pump can be completely taken apart, checked over, and put back together in two hours.
Thanks for your very informative reply. That's one less project to worry about! Here in industial Houston there are bound to be some good pump shops. Just a matter of finding them.

Peyton
 

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Discussion Starter #14
red suburban;1565457; said:
there is almost no older diesels in my area either.

good about the ac and rear air, very good that it wasnt the tow vehicle as well.

how easily did the truck fire up? i know here in texas it doesnt get that cold (i'm originally from houston, harris county). water in the fuel can be a problem with the amount of humidity in houston, but if you dont let fuel sit in the tank for long periods of time (months) then it shouldnt be a problem. did you look at the rear doors/tailgate? if it had barn doors you dont have anything to worry about back there, but if it had a tailgate did you mess around with the rear window?

from what you've posted here i'd say go for it. staying at 70mph on the houston freeway wont be a problem, you dont live anywhere even near mountains so thats no problem.
I was very impressed with the way it started. According to the maintenance mgr, it had been sitting for a month without starting. After the glow plug light went out, it started on the 1st turn and idled smoothly, if not quietly. I let it idle for a couple of minutes before driving it and it was smooth. It has the barn doors.

For whatever reason, either there aren't many older chevy diesels here or people just don't sell them. I really appreciate the info and support.

Peyton
 

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good, sounds like it should be a basic/reliable vehicle then.
these motors are loud, just a characteristic of old diesels.

old diesels in texas, not many were bought here, and those that were their owners dont want to give em up.
 

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That sounds like a very well maintained vehicle. Sounds like a very good choice to me.

The 700R4 is the weak link... Make sure it's working good. Make sure it shifts firm and predictably. Make sure it downshifts if you step on the gas.

The injection pump will probably last for a while yet. The injectors are technically towards the end of their useful life without service, but many of them will go for 300,000 without repair.

Prices on trucks around here really vary depending on the condition of the body... There's a million of them for four or five hundred bucks, but most of them are nothing more than transportation (rusty)... To get something decent you've got to spend like $1200. Of course, there are always incredible deals if you are in the right place at the right time...
 
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