Should I buy this Suburban?

[gymcarm]

After a quick search, I have a few questions. I am looking at a 96 K2500 Suburban, 6.5 TD and 4.10 (or so) gears. I did not hear the turbo at all during a test drive of about 35-40 miles. It smokes pretty good when I get on it too. Otherwise, it seems to run good. It has good get-up-and-go, but that may be the gears. It is an LT with all the options. It is very quiet in the cabin unless it is idling and then it resonates. I think I can hear the turbo thru the exhaust at idle. It seems to whistle while idling.

I am also wondering about fuel mileage with the 4.10 gears.

My only other diesel experience has been a worn out 6.2L and I currently have a Ford Super Duty diesel. No mistaking the turbo whine on that one!

I am concerned about the turbo and the smoke. We are supposed to go look at the truck again today and possibly make an offer. Any help is greatly appreciated.

Jim

[rjschoolcraft]

How many miles are on it?

You will hear very little turbo whistle in stock form. My 95 smoked under heavy acceleration and load when I first bought it. Replacement of the injection pump under warranty cured that problem. Applying the listed mods has brought the truck to life. Now I hear the turbo all the time and have much better performance. There is more in this engine that will eventually be tapped.

Hope this helps. ;)

[gymcarm]

It has 99,800 or so miles. I believe it to be stock. It sounds like you think it may be OK. Is there a definite way to check?

Any ideas on fuel mileage with 4.10 gears?

Thanks for the info and quick response.
Jim

[Don H]

I have a 96 2500 with 4.10s, I also have
33-12.50-16.5 tires on mine. The speedometer has been adjusted for the tires and I curently get about 15 mpg. It has 240,000 and still going strong,

[rjschoolcraft]

The pump is still under GM's warranty. If you buy the truck, the first thing to do is take it to a dealer for injection pump diagnosis. You will likely get a brand new pump under warranty.

My Suburban with 4.10 gears gets just under 16.0 mpg highway solo and averages 8.0 mpg towing my travel trailer. It would probably do better if I slowed down. Seems I'm always in a hurry.

As I said previously, mine smoked heavily at power. The new pump cured the problem.

[tanker]

Any history on this truck? Are you buying private, used car dealer, or a new car dealer? Any warranty, IE: 90 days etc?
I have 3:73 gears and get about 14mpg around, back & forth to work. Best was 18mpg solo. Towing I get 9 to 13 depending on terrain. Engine rpms are the main factor on MPG's If I run 60 mph I get great mpg, but I run with everyone else on I-95, 75+mph and that takes me down to 14 or so solo. I don't tow at those speeds.
If you are going to tow a heavy trailer 4:10's are great, but running solo at high speed will cut into your mpg's. I would guess the differance between 3:73 & 4:10 is about 1 mpg. You could put bigger tires on when its time to replace them, and that would increase your mpg.
Did you look at what the Kelley Blue book lists this vehicle. In one way Diesel suburbans are in demand in some parts of the country, and others won't buy them because of all the injector pump problems people have had. But you are in luck with the new factory injection pump warranty.
Wish you well on this truck. ;)

[gymcarm]

Thanks again for all the input. Went back to look at the truck and bought it. The turbo works fine. Had to have the windows down to hear it. The smoke is there, but not as thick as I remembered. Definitely not what I would call excessive. I am getting it from a used car dealer with no warranty except the remaining factory. It is in the shop at a Chevy dealer now getting the ABS light repaired and a couple of other small things.

As far as value, I am sold on diesels and am willing to pay a little extra for a good one. I think this is a good one.

Thanks again and I will keep up on the injector pump.

[gymcarm]

Tanker,

I would guess that the "break point" for mileage comes around 2000 RPM? What do you think? This truck tachs about 2400 at 70 MPH.

[MikeC]

gymcarm,

My 96 Burban wityh 3:73 gears is at about 2400 at 70 MPH if I remember correctly. To be sure about your gears go to the main page of this BB and there is a link for RPO codes. The codes should be on a sticker on your glovebox.

I bought mine in June of '01 and have modded it out. There is an article about the selection and mods in the reader's rigs section. If you need ???'s answered about the burb or the oddball parts we seem to have, feel free to contact me.

Good luck, hope you like it as well as we like ours.

Mike

[WAPATI]

While my 96 is a C2500 HO the the engine and drive train is the same.

My truck is a VIN F which is the high out put version.

It has a GM 5 turbo and I very seldum hear the turbor but, the boost gauge shows the turbo is working.

I put the 3.5" exhaust system on my truck and when it is ideling and I am at the back of the truck I can hear the turbo sound that is a low whistle.

From watching the guages and seeing a light black cloud when I'm pulling hard I have come to believe the computer is set up to increase the fuel to cool the pistons and other parts.

As soon as the truck levels out the black cloud goes away and the boost drops off.

Hope this helps.

[ANXIOUS-SUBMAN]

I have a '99 that I bought in Feb of 2001. With 4:10s at 70 I run about 2500 rpm and get about 17mpg. If I go 75 it drops to about 15.5mpg and thats loaded with people and gear while driving thru the smokies. Not many mods on mine yet. Love the truck.

Have fun!

[gymcarm]

O.K. I did some more reading about this engine. I stumbled across the crankshaft dampener articles and such. This Sub is knocking at the front of the engine. The knock is not horrible, but is noticeable. There is a verrry annoying resonance inside the cabin at idle. The resonance goes away if you increase the engine speed just 100 RPM. The truck has 99,800 miles. We have not taken delivery yet as it is in the shop getting the ABS repaired. General consensus is that the dampener goes out around 100K miles. Seems to me that I should be OK if I go ahead and replace the dampener and press on. What do you folks think, should I still get this truck? The last thing I need is a busted crank next week while the wife and kids are out somewhere.

[MikeC]

Vacuum pumps are also known to make noise and they are located, at least on my 96, just below the alternator. Just an idea.

Mike

[rjschoolcraft]

It's probably not the damper itself, but the crank pulley that drives the accessory belt. This is common on these engines. The description that you gave matches the occurrence on my 95 last year. The vacuum pump has also failed on my truck causing a loud knock...however, it did not go away with increases in speed...it got louder. On my truck when the pulley failed, the A/C compressor caused it to get worse when the clutch engaged. It is an easy fix, but cost nearly $200 for the pulley IIRC.

[gymcarm]

Thanks for all the info. My concern is that I don't know how long this part has been bad.

RonnieJoe, how long did you drive your truck with a bad pulley? Does anyone think it may have a damaged crank? Would oil analysis show anything if the crank is damaged?

Also, I read in another post that NAPA has the pulleys for about $70. I need to check into that.

Thanks again. I am trying to decide if I should get this particular truck or let it go. The dealer said he had people lined up to buy it. I would rather settle for a gasser than have the engine in this one go while on my watch.

[mhagie]

gymcarb,There is no way to accurately predict the demise of the suburban.
IMO a new balancer would be a wise investment,but in the long run its just like buying any used vehicle gas or diesel you can get a lemon.
A conversation with previous owner can be helpful if possible to contact.
A 2500 series suburban diesel is one of the best all round vehicles ever made you can have your cake and eat it to,they are a car,a truck,a excellent tow vehicle.
Bottom line is to buy the sub at a price where you have a cushion, if you will, in case you have to spend a little on it.
Take it out on a test drive and flog it a little if nothing happens good chance crank OK.
what ever way you go good luck in your venture. :D

[gymcarm]

mhagie,

Sounds like good advice. We drove it for about 45 minutes on 2 occasions. I also think it will be OK. Just wanted to know if the failure begins immediately or not. When some things begin to resonate, the failure comes VERY quickly. Since there is no one saying this happens with these cranks, I will buy the truck and find out where the noise is coming from. Then, repair as necessary.

Thanks for the advice.

[rjschoolcraft]

I drove mine for about six months before I figured out what was wrong with it. The actual mileage accrued was 17,530 miles from failure of pulley to replacement. I thought it was the power steering pump...I put two on it thinking that I had received a bad replacement. I finally noticed that the rim of the pulley had slipped relative to the hub. The slippage occurred when the alternator bearing locked up...that stopped the belt and all the accessories. The crank pulley burned through the belt because the belt was slipping against it. The sudden stoppage caused the rim to slip on the hub. I believe the rubber in the pulley was nearing the end of its life anyway and this just finished it off. The noise was present from that point on (after replacement of alternator and belt).

I personally don't believe that this can cause a crank failure. I know that others have said it can, but I believe in those instances the pulley failure was secondary to the crank failure. I now have over 42,000 more miles on the truck since replacement of the pulley with no apparent ill effects.

[gymcarm]

Thanks ronniejoe. That puts my mind at ease. Just knowing it takes a while...if it does indeed cause crank failure.

[mhagie]

With the thought in mind that crank failure might not occur right away if at all,it would probably be wise to schedule its replacement ASAP for if nothing else but peace of mind.
Also does not the serpentine belt have a torsional damper? My 6.5 has v-belts so I'm not 100% sure on the newer ones but I believe they do, that would be something else to check,they are just a mini balancer.
A close inspection of both might be in order. smile.gif

[rjschoolcraft]

The crank pulley is the damper for the belt. The crankshaft torsional damper is behind the pulley (the pulley actually mounts to it). When the pulley is removed, inspect the damper. If the thin rubber material is extruding from between the steel hub and steel inertia ring...replace it immediately. My crank damper didn't need to be replaced.

The pulley is most likely the cause of the noise. When the rim slips relative to the hub, there are "second chance" drive dogs on the spokes of the rim that contact the sides of pockets in the hub. They make a clattering noise when they contact.