hmmm Cadillac Seville Diesel - Page 3 - PeachParts Mercedes-Benz Forum

vstech · #31 03-20-2008, 09:08 AM

ok, my .02...
we bought the 79 when in came out, and after replacing 4 sets of head bolts, along with different matching head gaskets (they had to match thickness to get the CR right... ), having cracks fixed, replacing heads etc... the transmission reverse went out... something about High gear sharing reverse or some such... Junk tranny, anyway, we traded it for a prototype small wheelbase van in 83... don't get me started on that POS... anyway, we really liked the GM 5.7, but it was a demo vehicle we got from a dealership that was going out of business, and I guess it was not treated as well as it should have been. all in all it was a great vehicle that had major problems with longevity.
in 86 or so, we found an identical to our old caprice, and bought it for fun. we had learned a lot about the cars by then, so we took a chance on a 500.00 car. first thing we did was drop the tank and remove the fuel sock... (large sock like structure that serves as a tank screen, but gets clogged up really easy) then we put in a large seperator in the fuel line and replaced the GM filter. that thing MOOOOOVED! it had soo much more power than the 79 we owned! (it was an 81 I think...) anyway, the car never gave us any problems, untill it was rear ended when I was driving some kids home... the wagon sure did have a weak rear sheetmetal body... back door never did close right again, and I parked it until the city made me crush it.
that car is what made me get into MB diesels... I will never look back.
I say get the car, have fun in it, but don't expect it to come close to your SD...
let us know how you like it.

jcciem · #32 03-20-2008, 09:12 AM

NADA wholesale valueguides at that time, for all GM diesels, said "Deduct 50%of total value if equipped with diesel engine"

asnowsquall · #33 03-20-2008, 09:37 AM

Hey maybe you found a "bargain" and like most of us enthusiest can get it and keep it running. Depends how motivated you stay. Myself, I can loose interest quick, especially if it turn into a POS. But then again, maybe you can flip it on Ebay. Best of luck with whatever you decide.

The car is assless.
Another thing to consider is that all those gizmos that Caddy puts in turn to crap and get expensive with age. I had a rich uncle that gave caddy's to my grandparents and they were beautiful in their own way, but they get junky with age IMO. If you really want to make an offer go lower than $500 in my book. Hey, look at the price of diesel. Its got a big V-8. Thats just me.

cjlipps · #34 03-20-2008, 10:00 AM

This was in 1982 or so. It was doggy but didn't give me any trouble and got 24 mpg on the highway. Try that with dual 20 gallon tanks! They had a horrible reputation and I actually had to change engines to sell it. It had the TH400 tranny which is always a plus.
I say buy it for less than $500 (maybe way less) but don't ever expect to be able to re-sell it. Offer the guy $300 and give him your phone number. Judging from my limited experience and the opinions in this thread, you should have very few if any people competing for the purchase of this car. Of course if it's too low an offer for him he might just keep the car and thrash it. A guy could easily have $300 worth of fun with that car and crush it the next week.

ARINUTS · #35 03-20-2008, 11:13 AM

Speaking from personal experience, the diesel in the early 80's caddys were totally junk. I had a 81 ElDorado diesel. it was a regular 305 V8 converted to run on diesel. It wasn't a designed diesel. it was designed gas. stay away. GM did some strange things back then ( like the 4,6,8 )

#36 03-20-2008, 11:15 AM

Quote:

Originally Posted by ARINUTS

.... it was a regular 305 V8 converted to run on diesel. It wasn't a designed diesel. it was designed gas. stay away.

The urban legend that just won't die.

vstech · #37 03-20-2008, 11:23 AM

Quote:

Originally Posted by ARINUTS

Speaking from personal experience, the diesel in the early 80's caddys were totally junk. I had a 81 ElDorado diesel. it was a regular 305 V8 converted to run on diesel. It wasn't a designed diesel. it was designed gas. stay away. GM did some strange things back then ( like the 4,6,8 )

the 305 is a chevrolet motor
the 5.7L diesel is a Detroit Diesel made to dimensionally fit into an olds frame vehicle.
the ONLY thing that is similar to a gasser is the bolt pattern and motor mounts...
learn, don't spout.

DeliveryValve · #38 03-20-2008, 12:10 PM

Quote:

Originally Posted by ForcedInduction

Not so, the 5.7L diesel was PURE DIESEL. It only shared cosmetic parts with the g@s engines.

That was popular because of the Diesel's 4 bolt main, strong block and crank.

I'll say it again, they were NOT converted g@ssers!

Actually they only came in a 2 bolt main set up. But there was enough meat in the webbing to add in four bolt main caps.

Bajaman · #39 03-20-2008, 12:13 PM

Quote:

Originally Posted by ARINUTS

GM did some strange things back then ( like the 4,6,8 )

Too bad Chrysler is copying them

Dee8go · #40 03-20-2008, 12:17 PM

Style-wise not one of Cadillac's best incarnations of the Seville IMO. The first Seville was the best, I think.

Those GM diesels were just converted gas engines, weren't they?

Jim B. · #41 03-20-2008, 12:38 PM

Quote:

Originally Posted by Craig

The urban legend that just won't die.

That was no urban legend.

It is absolutely true.

Jim B. · #42 03-20-2008, 12:39 PM

Quote:

Originally Posted by Dee8go

Those GM diesels were just converted gas engines, weren't they?

Basically, yes.

That was why they didn't work, and soured the US public on Diesel engines.

Shawn D. · #43 03-20-2008, 12:56 PM

http://en.wikipedia.org/wiki/List_of_GM_engines#Diesel

http://en.wikipedia.org/wiki/Oldsmobile_V8_engine#LF9_350N_Diesel

Quote:

In the face of the 1970s 'gas crisis', GM turned to Diesel power for economic benefit, directing the Oldsmobile division to develop a V6 and two V8 engines, to be shared with all divisions.

These Diesel engines were designed to fit into the engine bays of gasoline powered automobiles, but despite popular belief, they were not "converted" gasoline engines. Oldsmobile's diesel engines, the 5.7 L LF9 and 4.3 L LF7 V8s and 4.3 L LT6/LT7/LS2 V6, were notoriously unreliable, particularly in the earliest versions, though reliability had improved by the early 1980s with the advent of the DX block, along with better fuel filtering and water separators. By the early 80's,the 5.7L diesel was a fairly reliable engine with the introduction of the rollerized camshaft/roller lifter combination and had many improved enhancements that the late 70's 5.7L diesel engines did not have. Many of the reliability issues these engines developed were a combination of faults not just related to design. Many of these engines suffered major malfunctions from poor quality fuel, mechanics not properly trained in diesel repair, and even improper owner service and maintenance. Although over one million were sold between 1978 and 1985, the failure rate of GM's engines ruined the reputation of Diesel engines not just built by GM, but overall in the United States market. Eventually, a class action lawsuit resulted in an arbitration system under the supervision of the Federal Trade Commission where consumers could claim 80% of the original cost of the engine in the event of a failure.

The Oldsmobile 5.7 liter engines experienced a wide gamut of malfunctions. One of the common failures was with crankshaft bearings. This was frequently attributed to owners and maintainers running the engines on SG rated oil (intended for gasoline engines), versus CD oil (intended for Diesel engines). This prompted GM to introduce the DX block which then allowed extended oil change intervals to 5,000 miles (8,000 km). D block engines required frequent oil change intervals because of the friction created between the typical flat tappet camshaft and hydraulic lifters. When the oil change interval was ignored,excessive wear was placed upon the camshaft and lifters. In 1981 when the DX block was introduced, the rollerized camshaft and roller lifters did away with any possibility of worn camshaft lobes because of reduced friction. These engines also suffered from blown head gaskets, warped heads, bad injector pumps, and bad injectors. The beginnings of these problems can be attributed to poor quality diesel fuel that may have contained water or other contaminants. These materials would damage the inside of the injector pump, and then eventually clog injectors. If water was injected into the engine, it could cause a "hydrolock" which would blow head gaskets and bend valves because water is virtually incompressible. This was the reason GM equipped later cars with water detectors and double filtration systems on their vehicles.

When a hapless owner took the vehicle in for repair, the mechanic would resurface the head, making it thinner, install a new head gasket, and then reuse the old, stretched-out fasteners. It would not be but a few thousand miles, and the vehicle was in the shop again for head gasket failure or a warped head. Nowadays high performance head bolt kits are available to do away with the problems the 5.7L diesel engines had such as the blown head gasket fiasco. Performance bolt fasteners when used within the 5.7L diesel will then make it a bulletproof, reliable design. The frustrated owner would frequently just get the shop to convert the engine to gasoline after a few repeated failures like this. As a side note, these diesel engine blocks were frequently sought by hot-rodders to build high-performance gasoline engines because of their extra heavy duty components which would withstand extreme horsepower.

Now, I guess I should expect to see the usual anti-Wikipedia rants, saying something like "Don't believe everything on Wikipedia" or "Wikipedia has lots of stuff wrong." Don't bother to dispute the articles unless you can prove their references are incorrect.

AdvisorGuy · #44 03-20-2008, 12:56 PM

Quote:

Originally Posted by Jim B.

That was no urban legend.

It is absolutely true.

Exactly... If it's on the internet, it must be true...

SwampYankee · #45 03-20-2008, 01:02 PM

Quote:

Originally Posted by thesst

Does anyone here have much experience with the old GM diesels?

I'm looking at buying an 84 Cadillac Seville diesel (with NO leaks

) that needs a new oil pump (about an $80 part). Body and interior are in beautiful condition.

So what do you guys think? Is it worth the $700? Or should I try to talk him down? I was thinking just getting a non-leaky running GM V8 diesel might be worth almost that much...

thoughts, comments, etc?

If it's minty fresh, wth offer him $400-500 and see what he says. If nothing else for the novelty. Be sure to put a good aftermarket water separator, replace the filters on it and drive on. There were some engineering concessions, but poor fuel quality back then and inadequate filtering/separation caused many of the problems. Diesel + water + compression (there were also some coolant leaking issues that did the same thing), with water not combusting only increasing pressure, caused stretching of the head bolts until the heads lifted causing failure. If it's still running chances are it's going to continue to do so with some care and due diligence. I've always kept an eye open for a nice example just for the novelty aspect, just haven't come across one yet that I'd jump on.