1984 GMC 6.2L Turbo Diesel

[BigMike]

A friend of mine is looking at buying an 84 GMC 6. 2L Turbo Diesel PU. Has 160,000 miles, AT. It apparently is in great shape and has been used to tow a fifth wheel. Would appreciate any advice/opinions anyone might have on the quality of that engine.

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1999, 2500,4X4,QC,5spd, KN Filter,VA Box,4" Exhaust, Piller Mount Pyro & Boost Guages, BD Exhaust Brake, Bugshield w/eyebrows. Bedliner, Diamond Plated Rail Protectors, Better Built tool box, Rear Flaps.
Pull a 2000 30. 5' Terry Manor 5er.

 

[jt1]

I owned a 89 4dr dually with the 6. 2 & 4spd in my const. bus. It was weak compared to the cummins, and noisy, but we put over 300K miles on it, with some pretty rough treatment. Bought it new, replaced the injection pump @ 160K, and starter @ 200K. Glow plugs can be a problem, if you crank it with the "wait to start" light on you will have very short glow plug life. The 6. 2's have small oil capacity compared to the cummins and it is important to change the oil every 2500 miles or the oil will break down and shorten engine life considerably. Overall a good, tough old truck, wasn't disappointed.

 

[Ross]

I had a 82 3/4 ton with the auto for 6 years. Put 217,000 miles on it. Replaced injectors at 90K, Pump overhaul at 150K, and rebuilt transmission at 180K. The engine was reliable, but had no real power to speak of. Back then, with 55 mph speed limits, it was just barely acceptable. For a daily run-about, I'd own another one, provided it was very cheap to get into. I would never tow with one, now that I've seen the light and bought a cummins.

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98 QC 3500 4X2 ISB 5-speed; 10-level Competition PowerMax; DD Stage II's; 4" exhaust turbo to tip; Luk ProGold; K&N; Amsoiled; Pillar Mounted Boost & Pyro; etc. , etc. ,

 

[danandamy]

6. 2 litre TURBO diesel? Stock these weren't turbo. Does it have an aftermarket kit on it? If so, they didn't hold up to well with aftermarket turbo set ups on them. I personally like the 6. 2 in full size Blazers and Suburbans. Great fuel milage, though gutless. They are gutless enough as to be completely worthless in a truck that's going to tow anything, though.

Daniel

 

[maint.man]

Mike, A good friend of mine has a 3/4 ton suburban /w/ a 6. 2 /w/ a Banks turbo and 135,000 It actually runs pretty good (not a Cummins , but what is) and he seems to like it .

 

[Lil' Dog]

A friends dad had a crew cab 2wd with the ATS turbo on it. Great power (compared to the original 140 Hp) but used oil like crazy if the boost was too high (above 5-7 Psi). See, the crankcase ventilator goes right into the intake, as soon as he got to a hill he was dual fuel!!!... . Diesel and 10W30. The truck needed a day-tank to keep the crankcase full of oil. Replaced her with a 454 and never looked back.

J-eh



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Jason Hoffman
Lil' Mack - 89 D250LE 5 Spd 3. 54 LSD Reg Cab. K&N,"tweaked pump", BD Injectors, Banks Pyro/Boost, 3. 5" Exst tail section straight. E&M Custom seats. Bosch H4, PIAA 80W/80W HdLites. 100W Drv,55W Fogs.
237,500 miles (380,000 Kms) 7850 Hrs. Cummins Power Booster member.
The Original Turbo Diesel

Lil' Mack Pics/March 2001

 

[Davison]

Check my post on Illflem's '200K on a 6. 2:... " about mine.

I didn't have a turbo, but even with one, I'd save up, or make more payments and get a "real diesel".

Sign me: Burned

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2001. 5 2500 SLT+, QC/LB 4x4, ETH, 6spd, 3:54 LSD, camper/tow equip. , NV241HD, Bright Silver, Snug Top, Ispro w/3 pod pillar w/tweeter, Pyro, Boost & Mag Hytec cover w/temp gauge, "de-badged", Snug Top Sportman's Option, EIDE Electic Boat Roof Rack, and Trans Flow 74 gal Aux fuel tank, dragging a '98, 28' Holiday Rambler TT.

 

[rickhans]

I still have my '83 1/2T 6. 2L Suburban 4wd, now with 4:11's, and around 230k miles. The first thing you need to know (if it is a 1/2T), is that the 700r4 Automatic, at least in '82 & '83, was a real dog. GM got sued over the quality and they ended up extending warranties. Mine was rebuilt the first time at 55,000 miles. The dealer wanted to charge me and they argued with the district service rep whose boss said fix it, no charge. Since then, it has been re-built 3 or 4 times, by 3 different shops. It is now sitting again with the transmission out after an oil change shop put slick50 in during a fluid change and caused the clutches to slip. I am waiting for a 400 transmission to come along to replace the 700R4. All 3/4 and 1Ton 6. 2L Chevys had the 400 Auto.

Some people have had good luck with that transmission, but I would not have one again, especially behind the diesel. It has a different torque converter and valve body. One from a gas engine Chevy won't work. Mods for the gas version can't be done to the diesel version (according to the shops that worked on mine). I also had a '94 K5 Blazer with the same transmission but gas engine. It lasted to about 110,000 before first re-build.

Other than that, the 6. 2 runs good and tows fine until you hit a hill. That's why I changed to 4:11's. I towed around 6 to 7,000 pounds and got 13 mpg at 65mph, and could maintain that on mild grades, but have slowed down to as slow as 35 on steep hills in Texas.

They fixed the injector pump problem on those around 1985 or 1986. I never had a pump problem after that.

One other item. I met an RV'r who towed a pretty good size camper, probably a 20 or 25' behind his mid-80's Suburban with the same engine and transmission. He installed a Banks turbo-charger and 4:11 gears, but said it did not improve performance much on the hills.

Personally, I can't imagine why anyone would want to buy an old Chevy with a 6. 2 unless it is to replace the engine with a Cummins. I don't plan to ever sell mine, but hope someday to do something wild with it since it is a 4WD. My wife says I'll probably be buried in it, but will keep the Ram for the kids to drive.



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98. 5 24V QC 4x4 SB 3:54 5sp

 

[Power Wagon]

Originally posted by BigMike:
A friend of mine is looking at buying an 84 GMC 6. 2L Turbo Diesel PU. Has 160,000 miles, AT. It apparently is in great shape and has been used to tow a fifth wheel. Would appreciate any advice/opinions anyone might have on the quality of that engine.

160K miles is a lot, especially on a turbo engine. The secret to keeping these things together is to change the oil a LOT and to use the RIGHT oil, as well. Also, on the turbo engine, it's essential that you have the pump set up for a turbo and someone with a lot of experience time it, as well. To much advance and/or too much boost and it'll blow head gaskets.

One of the ways to check the health of the engine is to run it with the crankcase ventilation open to atmosphere. If it you get more than a little trail of blow-by, I'd skip on it. We've seen trucks that seem to run nice with a turbo, but when you open the crankcase, they stream a solid column of smoke out, and even more when you work it. SOME blowby is normal, however, just to keep this in perspective.

The turbo is great for adding another 20 - 30 horsepower and keeping the smoke down and EGT down while doing it. Just don't expect any fantastic performance. And don't expect to make a 700R4 hang together towing a big 5er.