Opinions on 6.2 diesel
 

I'm looking at a squarebody truck with a 6.2 diesel. My wife wants a truck of her own and found one that she really likes.

It's a 6.2 diesel non turbo. I know these don't have a lot of power but I do want something that can be freeway driven and that my wife will enjoy.

Are there any known issues I should look for? Or should these just be avoided all together.

I would appreciate any information or help, thanks.

Re: Opinions on 6.2 diesel
 

Some of the parts such as the vacuum pump are not very common. Find out what the rear end gears are. The 6.2 doesn't like high RPMs. IIRC the happy place is 2000-2400 and they are limited to about 3600. With the proper rear gears or overdrive transmission, should make a good highway cruiser.

Make sure the starter has the front end support. Often missing and a missing one can lead to broken starter bolts or engine casting at the starter pads.

Re: Opinions on 6.2 diesel
 

Never owned one, but I've never heard much good about them either

Re: Opinions on 6.2 diesel
 

The achilles heel of them is the harmonic balancer. I’ve got an 84 that has been turbocharged since day one, and have had no issues. Maintenance is the key to their longevity. My K1500 is 6.2/sm465/3.42 with 33s and consistently gets 22-24 mpg. With the 9lbs of boost, if a gas burner isn’t careful, he will get a run for his money. I’ve also had them (both 1/2 and 3/4 tons) without a turbo. The boost makes it a totally different vehicle.

Re: Opinions on 6.2 diesel
 

I had a couple of them back in the day, my favorite was an 82 GMC Suburban 4x4.
Power was low. but it had the 40 Gallon tank option and I could go 700 miles between fill-up. Mine went thru transmissions, 700R4 was weak sauce behind the diesel. Also avoid the 8.5" rear end, they are weak as well. Luckily mine had the 12 bolt and was trouble free. Engine never failed, I think I had to put a glow plug controller of some sort on it, otherwise good.
Good luck.

Re: Opinions on 6.2 diesel
 

Thanks for all of the feedback. I'm hoping to go look at it on Friday.

Re: Opinions on 6.2 diesel
 

Hope you’re taking the boss (wife) with you.
I’ll betcha she won’t like the racket that diesel will make whilst cruising.

Re: Opinions on 6.2 diesel
 

I've had several, all military versions though. I've sold off all of the M1009 Blazers but will stick with my '93 military van as long as I'm around which has a non-turbo 6.2 and a 4L80 which is a great combo. They aren't as slow as everyone thinks and get great gas mileage. I love 6.2's.

They do make a ton of racket with the mechanical injector pump though so that's something you'll have to consider. I've never driven a civilian model and those had better sound deadening. My dad's '97 cummins truck is just as loud if not louder FWIW. I like the noise in something I'm not driving daily.

Check under the injector pump (top front of engine) if at all possible for signs of fuel leaks. The seals go bad and once they're leaking it's typically rebuild time. There's a shop in MI that is pretty good once you have it out of the vehicle which can be fun. Putting it back in and bleeding the lines is fun too.

Also listen for an erratic idle as this can be a sign of a bad injector pump.

When starting it, the 6.2 should start fairly quickly even in cold weather. Cycle glow plugs, pump throttle once, turn key at 1/8 throttle and it should fire right off. Missing and white smoke at start up are a sign of some glow plugs not working too well but not overly concerning as long as it cleans out and is running on all 8 within 5-10 seconds. When cold it should run on high idle for a couple minutes then automatically kick down to low idle.

They are a low RPM engine. Rev it too much and bad things might happen. Definitely sounds like they will at high RPM anyways.

Looks like I was changing a headlight when I took this pic. I use the van for hauling dirt bikes and parts to swap meets.

Re: Opinions on 6.2 diesel
 

Have an 86 K30 Dump with the 6.2 for over 10 years now and no problems. Many many CUCVs and my semi daily driver is an 86 M1028a1 I've had for 15 years now. Noisy and not so fast but dependable. Probably not a vehicle for someone that wants a quiet ride though.

Re: Opinions on 6.2 diesel
 

We've bought a gazillion cucv trucks over the years and although not a newer Cummins they are a pretty good engine...the lantern ring in the injection pump would fail due to sitting a long time and as mentioned above make damn sure the starter brace is present.otherwise a pretty efficient setup

Re: Opinions on 6.2 diesel
 

Well even though I'm considering swapping my 6.2 out, I don't have much bad to say about it. I drive 60-100 miles a day. City/highway loaded and/or pulling a heavy dump trailer. Mine has a slow takeoff, but otherwise hangs with traffic fine. I stay around 65, but can do 70 if needed.

Only issue I've had is a weak (original) starter.

I think IP and GP rebuilds are coming. And a snail. I guess I'm not quite ready to give up on this old diesel.

Re: Opinions on 6.2 diesel
 

My 82 K2500 originally came with one. It didn't have enough power for driving up and down the mountain that I live on, so I swapped it out for a 350 with a factory TBI setup and haven't looked back. I also didn't see the fuel economy everyone says they get in theirs. I was getting 13mpg, but that was with 4.10s and no OD, with a mixture of driving up and down the mountains in my area, as a well as some highway miles.

That being said, I personally wouldn't avoid another one, but I wouldn't put any serious money into fixing it either.

If you get it, I would setup the glow plugs for manual control which will make cold starts a lot easier. There are plenty of threads on how to do that. Be sure to get Acdelco 60g glow plugs if you do that though.

As others have said, make sure it has the front support bracket on the starter, otherwise you will likely break the starter pad off the block.

Re: Opinions on 6.2 diesel
 

I have an M1009 (Blazer, th400, 3.08 gears) and it gets 23mpg, and I love driving it. Get yourself a spin on fuel filter, and an electric fuel pump from a 6.5 turbo and ditch the mechanical fuel pump.

On the other hand parts are getting harder to find and diesel parts are just plain expensive to begin with.

If the injection pump were to die or something else expensive I'll be yanking it out for an LS.

Re: Opinions on 6.2 diesel
 

Someone put one in my 1972 GMC (build thread below).

Obviously it is not in the platform it was intended for, but I have to say that I like it. People accustomed to gas engines will note that it is not as explosive off of the line or when pulling out to pass someone, but really it takes off just fine at the lights and I cruise at 70-75 mph all the time: you just let it creep up to that speed and don't hammer on it.

A 6.2 is not for pulling as one might suppose, it is strictly a fuel economy engine. Many say it is like a 305, I would agree, but I would rather have a 6.2 than a 305.

And theoretically they should last as long without a rebuild as any other diesel - when cared for - which is to say 2-3 times longer than a gas engine.

Post pics: I just think diesels are cool and that's enough for me.

Re: Opinions on 6.2 diesel
 

Keep us "posted" on this. Would be cool to know how it goes.

Re: Opinions on 6.2 diesel
 

I really appreciate all of the feedback. Unfortunately the truck sold, time to start looking again.

Re: Opinions on 6.2 diesel
 

Bummer! Don’t shy away from owning a 6.2 or 6.5 in the future. As mentioned above, maintenance is key and just remember not to make them do more than they were meant to do: which is just cruise around and get good mpg’s. Great little engines if you enjoy good economy in a classic truck. And they are not any louder going down the highway than a gas engine if all the sound-deadoning mat is still present. You’ll really only notice how loud they are at idle. Unless someone has advanced the injection pump, then they get loud.

Re: Opinions on 6.2 diesel
 

I like a 6.2 Diesel. I daily drive one now and have had a few military 6.2s in the past.

Re: Opinions on 6.2 diesel
 

Typical day for my 6.2 powered truck. Quite a few city miles and a very steep and long grade to the dumpsite.

Re: Opinions on 6.2 diesel
 

I just purchased this 1982 Chevy with the 6.2 Liter Diesel . Picked it up for $700.00 . 6.2 , 4 spd overdrive , 3.42 gears , a/c , p/s , p/b , cruise control , etc . So far love driving the truck and its been great .. Gas mileage has been 19-22 on the road , it depends which way you are driving up the gorge ... lol

My thoughts are that I wish I had gotten one sooner .. Maintance is key , but a great new learning experiance .. Good Luck !!

Re: Opinions on 6.2 diesel
 

What a STEAL!! Congrats sir!

Re: Opinions on 6.2 diesel
 

My mother bought an almost identical truck in 82, only it was a Silverado and chrome rear bumper. Color was same, options almost exactly the same.

Re: Opinions on 6.2 diesel
 

What a great grab. That's a really nice looking truck. Pull the rack out of the back and you'd probably see the mileage tick up even a little more. Definitely take good care of that transmission since not very many 700r4s survived from the early 80s. Little bit of attention and I'll bet you that paint would come back really nicely too. Let us know if you want any thoughts or ideas on paint or maintenance. Would be cool to have you update any changes you make here.

Re: Opinions on 6.2 diesel
 

Thank you for the info . Yes trying to get rid of the rack now .. Always open to any help .. New to the diesel world , but enjoying it ..

Re: Opinions on 6.2 diesel
 

I just bought a 88 k30 with a fresh 6.2 and a 4 speed in it, it's getting a turbo and an nv4500, I'm not sure what gears are in it yet, the spid just denotes "standard gearing"