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Discussion Starter · #1 ·
Just recently got a 1980 GMC with a 350 diesel in it. The truck has been parked for about 6 or 7 years. The reason it was parked was due to some injector problems. The truck is in pretty good condition . I was wondering what these engines were like?? My plan is to see if I can get it running and use it as a DD .If any one has any information I would appreciate any help I can get to get running.

Thanks
 

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Did you try to start it?
 

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A Country Boy Can Survive...
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do not use ether or starting fluid to start it. ether and diesel's don't mix well. if you must use any "drugs" to start the motor make double sure your glow plugs are disabled and give it a whiff of WD-40, not ether. other than that if maintained i don't think these motors were as bad as people say they were. remember people spoke bad about the 6.2 and the 6.5 as well. GM's track record wasn't the best before the dmax came out it seems. word of bad experiences with the older GM diesel seems to travel faster than good experiences.

talk to dieselolds. he'll be able to tell you anything you'll ever need to know about the 5.7 diesel.
 
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5.7 was never a real good engine. Most took them out when they let go and replaced them with the 350 Oldsmobile gas motor.

DD > daily driver, if it ever ran good they were very fuel efficent but never a load hauler.
Quite low hp.
 

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the 5.7 was an option in a pickup?? when did they do that?
 

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The 5.7 diesel was introduced in cars and light trucks (1/2 ton) in 1978. It was installed in cars until 1985, and in trucks until the introduction of the 6.2 in ~1982. In 1980 or so it was redesigned... The original '78-'79 model was famous for durability issues, mainly centering around main bearings, and there was a relatively large lawsuit against GM about it. The redesigned engine was introduced and was significantly better than the previous one... Not a HD engine, but it didn't blow up at 50K miles like the first one. The early model 350 diesel was bad enough that it gave the diesel engine a reputation in the U.S. from which it has not fully recovered though.

But none of that really matters... Just run it.

It's very similar to an early 6.2 from a "get it running" standpoint. You need to get clean fuel to it, and crank it fast enough, and it should start...
 

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talk to dieselolds. he'll be able to tell you anything you'll ever need to know about the 5.7 diesel.
Dave,

Thanks for the good word.Much appreciated.In my opinion,they are pretty decent.I've had excellent success with those 5.7 diesels.Even the so called bad D blocks from the late 70's served me quite well.Those were supposedly the bad versions but i've used two D blocks that had a ton of miles on it.I kept the oil changed along with filter changes and basically I had driven each one sensibly.Never had a problem.

Maintain them well and it'll go the distance everytime.
 

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The original '78-'79 model was famous for durability issues, mainly centering around main bearings, and there was a relatively large lawsuit against GM about it.
They really did'nt have main bearing problems,at least not from the engines i've gone through.Just normal wear and tear on the bearings as any other engine would experience.

Some crankshafts did break,while others did not so it was more than likely a quality control issue.I've had '78 and '80 crankshafts go the distance without a single problem.Oil pressure held up great from start to finish.
 

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Discussion Starter · #9 ·
Thanks for all the replies, I will be asking questions once i get it home and start working on it. Are there still parts available for this engine through aftermart or jobbers suppliers??
 

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For the most part,many of the parts are still available.Although the injectors are pretty rare,they can still be reconditioned at a diesel shop.
 

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I had the 1980 GMC Sierra Classic 1500 6.2 Diesel. Best work truck I ever owned. The original engine was a gas engine converted to a diesel engine and that went out on me a little over 100,000 miles but when I had the new diesel engine that was the true diesel engine I had over 300,000 miles on that engine and it was still running strong like it was new still. Excellent fuel millage it was 21 miles to a gallon on average. I would load down the bed and haul a trailer loaded full and it had no problem, that truck hauled horses, ponies, and everything else for me. Miner repairs that if fixed every now and then. Mainly starter motor was the one thing that I had to replace every few years. The transmission was the problem with the year and model I had and GMC never made a different one for that year and model on mine and so around every 89,000 miles I had to have a new one put in but that truck was more than worth that on how great of a work truck and everything for me, so a $1,000 for a new transmission every 3-5 years was a lot cheaper than buying another truck. I wish I never got rid of that truck. If you need help just ask. I would buy the old shop manuals for that truck if I was you because they are detailed on everything step by step with excellent trouble shooting step by step. I owned mine for over 20yrs.
They hate to start up in cold weather so wait for glow plug relay system to go through the first three times goes on and off try but don't crack it over more than 30 seconds at a time.
Make sure there is over a 1/4 tank of fuel in your tanks at all times or the truck might start stalling when you go to stop do to how the fuel pumps are in them, so air gets in the fuel line and causes those truck to stall.
You run out of fuel the easiest way to get truck started back up after that is to keep filling up the fuel filter with fuel until it gets the fuel all the way running through with no air in the line. Glow plugs will last 5yrs and more and all you have to do is make sure when you test each one that each one is within a certain reading on the meter and only change the ones that read out of that range.
 

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I had 2 brothers (Customers) that were diesel technology instructors at rural Junior College.
They said if the 5.7L diesel had the heads pulled, and head stud kit put in that they would go a very long time.
one even put one in his 1983 Ford E-150 Van, he was on like 200K miles on that motor.

Then one of the brothers left the college & opened up a diesel repair shop for just cars & pick-ups, they did a lot of GM & VW diesel stuff in the 1980's, those old VW diesel Rabbits would get 50MPG's!
 
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I had 2 brothers (Customers) that were diesel technology instructors at rural Junior College.
They said if the 5.7L diesel had the heads pulled, and head stud kit put in that they would go a very long time.
one even put one in his 1983 Ford E-150 Van, he was on like 200K miles on that motor.

Then one of the brothers left the college & opened up a diesel repair shop for just cars & pick-ups, they did a lot of GM & VW diesel stuff in the 1980's, those old VW diesel Rabbits would get 50MPG's!
Yes those 5.7 diesels were decent I have to say.Some guys hated them like there was no tomorrow but I ran several of them without any issue.Just the common head gasket failure but that was remedied once I used victor reinz head gaskets and the arp head bolt kit.I used to torque the bolts in 3 steps going from 50,100 and finally 140 ft/lbs.

I was also inside many injection pumps on those because of failed flex rings which only lasted several years but stanadyne came up with a fix in 1985 that eliminated the flex ring altogether.
 
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