Is This the Least Reliable / Durable Chevrolet Pickup? 1978-81 C10 with the 5.7L 350ci Diesel

Learn about what's arguably the least reliable/durable Chevrolet pickup truck ever produced, the 1978-81 C10 2wd pickups with the Oldsmobile 5.7L 350ci diesel engine.

[michaelsullivan]

I had an M1009 (Military Blazer) with the 6.2L Detroit, and found it to be a great vehicle.

The diesel was backed up by a TH400 and 308 gears. Since it was emissions exempt, it was rated at 155hp & 240lbft of torque.

It would return 22mpg no matter what I was doing with it: 50mph, 70mph, loaded, light, towing. . . It didn’t matter, always 22mpg!

Great truck!

[maxhenry]

Love the styling on the ‘73 to ‘80 chevy pickups.

[shazbot]

I loved my 77 with the 250 and 3 on the tree. That thing was indestructible

[DSP]

"Pray to more than one diety." A priceless comment about these trucks, Adam -- I love it! I knew (and know) many people who have driven pickups since before these diesel-powered versions were introduced. They were not popular at all when new, and my guess is that they are rare indeed today. A great overview.

[mickeythompson]

Bad and Good memories. My Dad bought a 78 C-10 short bed Scottsdale trim with the diesel. It croaked at 40, 000 miles with heads cracked, cam lobes bad and it had at least three torque convertors go out. I was 17 years old in 1981 when he told me if I fixed it I could have it. I'm sure I contributed to its demise. I remember the governor limited it to 98 mph. I turned the breather lid over and man that thing would roar like the biggest 4-barrel you ever heard but wouldn't spin a tire. I pulled the Olds diesel out and put a 455 Olds gas hog in it place with a Holley 750 carb. All the accessory brackets were Oldsmobile, so you couldn't just drop in a Chevy. Now I had a truck, just needed a bigger fuel tank. I lived out in the country so when I went to town I had to gas up before I went home or I wouldn't have enough to get back to town!

[stacyshirley]

best truck i have ever kms when i sold it and bought a have kept it

[andoletube]

It amazes me that this channel doesn't have more subscribers. It's one of the most interesting car channels around.

[michaelcoonce]

I actually had an 81 diesel and it did me well. I wish I still had it

[chrisreynolds]

I actually found the diesel 350 easy to convert to gasoline keeping the same short block if it was an injection pump, injector or head gasket failure. Mondello Olds sold an inexpensive kit that had several plugs and caps in it. You yanked off the diesel top end, grabbed a set of reman 403 heads, SBO gas intake, GM Q-Jet and Olds HEI. Fitted the plugs and caps into place which could be done without even removing the short block. The diesel cam was a roller cam as well. You ended up with a flat top piston 350 gas engine with a roller cam that had big block mains and all the extra cast iron that got left out of the blocks of the 307s, later 350s and 403s. No windowed mains on the diesel blocks and the main webbing was 2x as thick as a gas block. The diesel pistons and rods were a bit heavy but the diesel cam was done at 4, 500 rpm but had a boat load more power running on gas. I did 5 of these conversions nearly 20 years ago. 3 trucks, an immaculate Cadillac and a Buick.

[labpuppyu]

Correction. The 6.2 diesel that came out in 1982 was designed and built by Chevrolet. Not a completely clean sheet of paper either - it shared a lot of design with the Big Block - Mark IV - gas engine. First year had head gasket problems too ... I fixed quite a number of them. The leak occurred at either the right front or left rear of the engine from a cooling passage that sat OUTSIDE of the head bolt circle. Gaskets sourced from Fel-Pro was the fix.
I put a lot of shoes on my kids' feet thanks to the Oldsmobubble 5.7. I got pretty good at fixing their quirks.

[marthasmadman]

Most people back then swapped in a 350 gas engine and at least those from the factory with gas engines were very reliable

[misterhipster]

Have a collection of 5.7 powered vehicles, two Olds full size, Caddy Seville, Eldo and the rare one, a 85 Fleetwood d' Elegance, half year model went to front drive 85 1/2. Has a unique injection pump, 85 only. 80 C-10 w/72k miles, barn find and guess what, blown head gasket. Replaced the short block w/a 81 DX, valve job, fresh injection pump she runs like a top and is actually pretty quick, on parr w/a 305 gas. 78/79/80 had pencil injectors hp was as stated 120. Late 80 on dropped the hp to 105/ two stage injectors, quieter operation and less smoke. The answer is ARP studs or bolts to secure the heads, however in the case of the C-10 I chose to use the late model GM head bolts, just to see how it would go, so it's going. Have a couple of 6.2 square pickups too, turbo'd them both, run pretty well that way. All that being said, first experience w/a 5.7 was a 81 Pontiac Bonneville Broughm bought in 82 for my wife, had it 10 years, lost an intake valve @ 52k, fixed it and ran it to 100k, it had a 200C transmission, needed a torque converter, due to decell check valve failure that caused a converter clutch shutter, other than that it was a reliable car, wife favorite, less trouble than the 91 Olds Touring sedan that followed, or the 98 Buick Regal GS sourced new that stopped on the freeway due to fuel pump relay failure that was an issue w/the super charged models. It's sad that the engines weren't treated to better head bolts and proper fuel filtering, they are good economical engines if properly applied. Prior to the Pontiac diesel we had a Pontiac Grand Am sedan, 10 mpg on the wifes commute, the diesel: 21.

[snowman]

I had a 1978 chevy pickup with a 5.7 diesel and I loved it it run great and yes they did some head issues and some bottom end problems but they got great fuel milage and by 1981 they had those engines figured out the 20/20 and the 60 minutes reports basically killed the engine. Yes they weren't designed for heavy pulling or hauling but we would pull a 26ft fifth wheel with ours you had to run it in second gear but it was geared high enough to do so and that way you could keep the ram's up at operating level and have no issues. The two biggest problems was GM didn't do enough R&D on the engine before it was brought out and the other problem was to many people buying them that had no business owning a diesel. And to the gentleman how said chevy designed and built the 6.2 he's incorrect Detroit diesel designed and built both the 6.2 & the 6.5 for General motors.

[alexinnewwest]

I had a 85 4wd suburban with the 6.2. It was a good engine. Never had any real problems. Just keep on top of maintenance, I’d say power felt like it was between a 305 and 350 but that 7000 lbs slug got 25mpg!!

GM designed these engines for MPG
The diesel power wars wouldn’t show up till the mid 90s

[ddellwo]

Those early square bodies were absolutely horrible for rust! Back home in Minnesota, after about five years of driving on salt-strewn roads, it was common to see the sheet metal on mid-70’s versions of this vehicle completely missing about 12” - 18” up from the rockers……😮

This “feature” gradually improved over the long production run of the square body trucks……🛻

[deedgrabber]

Your videos are soooo great. Love the lack of BS

[ppeller]

Wow Adam....you switched gears on us here. Tapping into the truck market is brilliant. The demand for trucks is huge today. So why not add them to your menu of automotive delectable tales of the past.
👍🏻

[annettesurfer]

I bought an Oldsmobile Delta 88 diesel at an abandoned vehicle police auction and discovered the torque converter sheared off all the welded fastening points. After replacing that, I found it smoked under acceleration, which stopped after the injector pump was rebuilt. It ran great but I soon tired of the drooping headliner and the smell of diesel so I sold it. I’m glad I didn’t experience any of the head issues they’re known for.

[rsn]

I’d like to see a feature on International Harvester trucks, Scout, and Travelall…

[seejayfrujay]

I remember vent panes that worked about 10 times, then the latch sprung. After that, it whistled at highway speeds. You had to slam the doors really really hard.