Goodwrench 5.7 GM Diesel engine

[winterset]

I know the late 1970's and early 1980's GM 350 diesels had lots of issues - that can be mechanically tied basically to bolts that were notlong enough, but most importantly - being the engines were new, no one understood the technology.

Diesels require:

clean fuel (no water to corrode the fuel delivery system)

regular maintenance of the fuel filter

2500 mi oil changes

Diesel motor oil like rotella

head gasket bolts should never be reused (because of stretching)

with the ~1984 re-design of the 5.7 and manufactured by Goodwrench and now with an understanding of proper maintenance of a GM diesel, I would like to see if anyone else believes this engine is worthwile?

seems the cosensus is this engine can run forever if properly maintained, and it gets super mileage.

[scott y]

What is your application if you don't mind me asking?

[winterset]

What is your application if you don't mind me asking?

I have been keeping my eye out for a 1976-1979 Seville. I recently came across one with 15k mi that had a Goodwrench diesel in it.

seems the ones that weren't torched for insurance fraud - survived, and GM eventually offered a gas or diesel replacement. a few of the Diesels are still around, usually with less mileage than gas.

[Texas Jim]

I had two of the diesels....way back then.

I had a 1981 Seville Diesel. (Darling Wife called it her Humpback Cadillac)

I also had a 1980 Oldsmobile 88.

I was one of the lucky ones.

I never had any trouble with either one.

To make then run decent, they need a true dual exhaust system...that helps them a "LOT"

I also had the pump turned up om them.

They would then run (performance wise) with the gas engines of the day and get almost twice the mileage of the gas engines.

[Ranger]

I too had an '81. It was a bigger dog than the 4.1. After the Roosamaster injection pump went, it blew a head gasket. That's when I dumped it. Don't know what if anything was changed so I can't speak for the later ones, but I wouldn't have one.

[hjb981]

What is a Goodwrench engine? Does it mean that it has been remanufactured by GM? I am also curious: what kind of mileage do those cars (with the 5.7 L diesel engines) get?

[Texas Jim]

What is a Goodwrench engine? Does it mean that it has been remanufactured by GM?

I am also curious: what kind of mileage do those cars (with the 5.7 L diesel engines) get?

I had two of them.

A 1981 Seville and a 1980 fullsize Olds 88.

The two that I had would get 25+ in town if driven normally.

They would get close to 35 on the highway driven at the interstate speed limits.

This was at a time that fullsize cars only got about 10 or 12 in town and 15 on the highway.

That means that the diesel cars got about "TWICE" the mileage that the gas powered cars got..

Also at that time...diesel was quite a bit cheaper than gasoline.

We put a lot of miles on the 2 cars...never did have any trouble out of either one.

I know they were problematic for a lot of people... I reckon I was one of the lucky ones.

[KHE]

By 1982 or 1983, the 5.7 Diesel was pretty much a bullet proof engine but its reputation was so tarnished, the public wanted nothing to do with them. If the car you're looking at has a recent Goodwrench diesel engine it will be fine.

The early ones had injector pump issues as well as the owners using 10W-40 oil in them which would sieze the piston rings resulting in no compression. Not to mention some owners using starting fluid or WD-40 to start them instead of plugging them in during the cold nights.

A friend of mine was in sales and had an '82 Caprice Classic with the 5.7 diesel - never any problems. Very nice, full size car and 35 - 38 mpg to boot. It lacked power but that was about the only negative.

[firefoot0315]

A friend of mine was in sales and had an '82 Caprice Classic with the 5.7 diesel - never any problems. Very nice, full size car and 35 - 38 mpg to boot. It lacked power but that was about the only negative.

Well it's not like the HT4100 was a powerhouse either. All else being equal, diesel sounds like a good choice.

[winterset]

THANKS all.

you helped me:

- verify the mileage. Yes, I have read several places of mileage being in the 30's on a heavy 1978 seville.

- Find the first place I can't use WD-40 (the injector pump)

- To keep my eyes open for another find. The one I was looking at got away!!

Perception is everything isn't it? Yep - as KHE said, Goodwrench Identified all the problems, and in My Opinion bulletprofed the engine.

[Ranger]

My 4.1 got better mileage than the diesel and while no powerhouse by any stretch of the imagination, it was WAY faster than the diesel.

[scottmudd]

Hi all,

I just purchased, and am having shipped to me in Arizona, a 1979 Cadillac Seville with a GM Goodwrench replacement 5.7 diesel engine. What should I be on the lookout for? The dealer that I bought the car from in Florida states that the injector was just recently replaced. Vehicle looks like it has 76xxx miles and that the GM Goodwrench diesel crate engine was installed at 50xxx miles. The only other diesel I have owned was a 1974 Mercedes Benz european 220D back in the '80's. Your help, input, and advice will be greatly appreciated.

What numbers should I be looking for for the engine once I receive the vehicle? Besides the Cadillac dealerships here in Phoenix, is there any other recommended plkaces i might take this car to for service and check ups?

Should I be concerned about the new low sulfer diesel gas for this vehicle?

[Texas Jim]

Keep the oil changed regularly... use Diesel rated oil ONLY.

Change the fuel filters every once in a while.

I am not telling "YOU" to do this... it is just food for thought.

I always did two things to any of the GM Diesel cars I had.

Put TRUE DUAL EXHAUST alll the way from the manifolds to the rear bumper and include and "X" pipe in the exhaust, up close to the transmission.

If you look at the factory exhaust, it is similar to the exhaust found on the gasoline engine.

In my humble opinion, the exhaust system chokes the engine and doesn't let it breathe.

The other thing I did was find a "GOOD" diesel mechanic that knows what he is doing, and have the pump "TURNED UP".

If he don't know what you mean when you say that... find another mechanic.

Both of those mods... done together... seemed to "INCREASE" both horsepower and fuel mileage, while DECREASING the amount of smoke the diesel would put out on heavy acceleration.

[KHE]

The Goodwrench replacement engine should be very durable. Most of the points have been covered. Use the correct oil in it, keep it changed regularly and it should last a long time.

I think the low sulfur diesel is bad for the injector pump as the sulfur is what lubricated the pump. You might want to ask Goodwrench what to do regarding the use of the low sulfur fuel.

[winterset]

I never did get my Diesel. One thing I did read is that when you drive an old American car, and pull up to a diesel pump, you are going to have a hard time convincing the gas attendant to fill it up with diesel. At the self serve, you are going to have people running to stop you from dispensing diesel. There are only a few American diesels on the roads.

[KHE]

I never did get my Diesel. One thing I did read is that when you drive an old American car, and pull up to a diesel pump, you are going to have a hard time convincing the gas attendant to fill it up with diesel. At the self serve, you are going to have people running to stop you from dispensing diesel. There are only a few American diesels on the roads.

Where is there a full service gas station these days? I think it has been 20 years (maybe 30 years) or more since I saw a full service gas station.

[winterset]

Full service gas stations can be found anywhere in NJ - It's illegal to dispense your own gas in NJ. Also NY city has full service. I think you can dispense your own, but there is usually an attendant

[KHE]

Full service gas stations can be found anywhere in NJ - It's illegal to dispense your own gas in NJ. Also NY city has full service. I think you can dispense your own, but there is usually an attendant

Interesting. I wonder why the politicians passed a law making it illegal to dispense your own gas in NJ?

[joeb]

Coworker had a cutlass v6 diesel and a full size blazer diesel. I swear they started the car in gear and moved. Maybe 2 sec warmup period. 1985? Gas was around $1/gal and diesel was 50 cents?

[Texas Jim]

Coworker had a cutlass v6 diesel and a full size blazer diesel. I swear they started the car in gear and moved. Maybe 2 sec warmup period. 1985? Gas was around $1/gal and diesel was 50 cents?

I never did do a "WARM UP" on any of the ones I owned either.

Start the engine.. put it in gear.. drive it.

[KHE]

The starting procedure was to turn the ignition to ON and the WAIT light would illuminate indicating the glow plugs were heating up. Once the WAIT light went off, the engine could be started and immediately driven.

[Texas Jim]

The starting procedure was to turn the ignition to ON and the WAIT light would illuminate indicating the glow plugs were heating up. Once the WAIT light went off, the engine could be started and immediately driven.

Correct..

I had forgot about the wait light till you mentioned it.

Summer in Texas it was usually just 3 or 4 seconds... winter would take a few seconds longer.

If you had recently driven it... the WAIT light might not even come on.

[KHE]

I forgot to mention that if it was recently driven, the WAIT light might not come on. There was also a WATER IN FUEL light that would come on as a bulb check and then go out. If it stayed on, the fuel system needed to be cleared of water.

[PAUL T]

My father-in-law has one in a Olds 98. It got 35 mpg on trips. He did not have any trouble with the engine, he just had to replace a couple of torque converters if I remember right.

[joeb]

friend had small shop and had many cars. he had early 90's chevy truck with a non-turbo diesel? or maybe it had a turbo but no intercooler? than a month later it was gone and he got a newer version with a nice shiny aftermarket intercooler. if customer did not want to fix vehicle, they sometimes sold them to friend for little to nothing. he had a 94 sts with a blown headgasket. for 1 month. used to bug me about my sts. his was $50 or something like that.