1981 Oldsmobile 98 Regency 5.7 diesel
A great, smooth, unusual car, kind of lost in the modern world, but still survives
The car is 31 years old and has truly been a great car. Very few cars even last 31 years.
A few power windows over that past 31 years.
Transmission leak at the front seal.
Engine rebuilt in 2000 (the car was 19 years old) at 75,000-miles. Not unusual for this new "Diesel" technology that GM rushed to market in the late 70's (oil leaks - low compression, coolant leaks, getting harder to start), but the engine never actually gave out.
Rebuilt engine has head studs, solid copper head gaskets, and a beefed up mains. I added a water separator as well.
Injection pump rebuilt in 2000 also. Was leaking a small amount of diesel fuel due to old seals.
Glow plug system converted to push button activation with all new glow plugs several times over 31 years.
2 alternators in 31 years.
4 or 5 water pumps in 31 years.
1 fuel pump - I converted it to electric in 2000.
I drove this car to work for 20 years. Just down the road. It always started (no matter how cold) and never had to be towed once.
The car has been great. It can get up to 33 MPG on the highway at 55mph if driven like a Granny.
In town with the A/C on - it will get 17 MPG or more. By the way, the A/C is still 100% original with a minor leak - 1 pound of Freon per summer.
The old car drives so smooth and the cloth pillow top seats are amazingly comfortable. The car is by far more comfortable than any car built in the past 20 years.
The diesel engine is a bit loud, but these cars have become so rare, that at gas stations people always walk up to talk about the car, once they hear the diesel clatter.
The power steering is so easy to turn, and the car drives like a real boat. The ride almost makes you feel like you are on water, as you can feel no road bumps whatsoever.
The car is probably not up to speed in today's fast paced "rat race" world, but it is sure nice to drive on a Sunday.
It is a great car from a past time in automotive history in the United States.
By today's standards the car is under-powered, but we have to remember why the car was built during the energy crisis, the car was built for MPG - not horse power. Jimmy Carter was still in the White House when this car was being built.
I still enjoy driving the car, and will never sell it. I love the smell of the diesel exhaust along with the sounds.
Would you buy another car from this manufacturer? Yes
Review Date: 22nd May, 2012
22nd May 2012, 06:54
Wonderful cars, great review. Some people have bad luck with the diesels - I've had a couple with the gasoline 307. What I've always wondered, was if the diesel went out, if it would be prohibitively expensive or difficult to change out the engine for the 307 gasoline?
28th May 2012, 23:13
Converting from diesel to gas requires that you actually have to physically remove the engine, and replace the whole engine with a gas engine.
You can use a diesel block and put gas heads and intake on it, and build one bad engine with 500+ horsepower. The diesel blocks are very thick and tough.
Most all GM RWD cars will easily exchange engines and transmissions, as they all share the same bell housing bolt patterns and engine mounting locations. Even the exhaust manifold bolts are in the same place.
Going from diesel to gas will require you to also change out the braking system, as on the diesel cars, the brakes were totally hydraulic - not vacuum assisted.
This conversion is fairly simply, and was done on a daily basis at most shops in the mid 80's. Today most shops have moved on to a younger employee pool, and I doubt that these kids even know how to tune a carburetor. I don't even know if they even teach carbs in AES schools anymore.
I remember it was hard to find a gas 350 or 307 to put in place of a diesel. 95% of people simply converted to gas, and didn't even want another diesel.
The 5.7 L GM diesel can be made to be fairly reliable.
You must start off with the DX block - 1981 or newer block. You should put in high performance head gaskets with super high strength head studs. You should add a water separator along with several fuel filters.
Always let the car warm up for at least 3-5 minutes - even when warm outside before you really get on the acceleration very hard.
In the cold winter time - you should let the car warm up for 7-10 minutes before pulling out of the drive way.
Always use a super high quality oil, and only use an engine oil that is specifically made for a diesel engine, and change your oil every 2000-3000 miles. Change your own oil if you can to make sure it is done right. I have seen shops put standard oil into these engines back in the day.
The main problem with these cars in the 80's, was that people didn't let them warm up. The diesel fuel back then was so full of water and dirt. The engine oils were prehistoric in terms of high quality lubrication and protection properties. The shops really had no idea how to really work on these engines. They even reused stretched out head bolts when replacing a blown head gasket - well the stretched out bolt was why the gasket blew in the first place.
I have seen many of these engines last 200,000 miles or more, and that isn't bad for a car of the late 70's and early 80's. Most gas engines back then were lucky to hit 100-125,000-miles.
With today's modern fuel injection and great oils, along with super clean fuels - all cars will typically go 200,000 miles with little to no problems - even cheap economic cars are better.
Just because of how old these cars are today, I wouldn't recommend one as a daily driver. Any 30 year old car is too old for a modern driver car. You don't have ABS, air bags, safer crash designs, etc. Also the car is old - the heater core is rotten and could blow out any second, suspension parts are old, on and on and on.
Don't get me wrong on the safety- I did see a few years ago a big early 80's Buick Electra get hit head on by a brand new Honda Civic. 40 mph. Both were 4-door cars. Both cars had mangled front ends and the Civic even had a bent up roof. The older lady in the Buick was not hurt. The girl in the Civic was bleeding all over the face - probably from the air bag, and her left leg had a protruding compound break between the knee and hip. When they hit, the big Buick slammed the Civic to a dead stop and then pushed it backwards 30-feet. I was gassing up my car and heard the old lady hit the brakes with tire squeal and blue smoke. The girl in the Civic was texting and never even hit the brakes. The crash happened right in front of me. The sweet steam of the antifreeze spewed out and I could taste it on my lips from the back of my car.
So when I say not safe - I am speaking in relative terms - not absolute.
29th May 2012, 11:27
"Most gas engines back then were lucky to hit 100-125,000-miles."
Really? All my V-8 American cars 60s, 70s, and 80s, and those of all my friends, family, and acquaintances routinely made it to 200-300,000 miles. At 100-125,000 they were just barely broken in.
Loved your story about the Buick/Civic crash. The big old ones were far safer. ABS and airbags are nothing compared to mass.
30th May 2012, 17:07
81 Olds Cutlass, 185,000 miles (before the odometer stopped working).
84 Grand Prix, 210,000 before the Buick built V6 got tired.
85 RWD LeSabre, over 140,000 trouble free miles before it was sold.
76 Ford Elite, I really don't remember this car, but I always hear about it hitting the 200,000 mile mark.
The Grand Prix was my 1st car, and I would give anything to have one again. The others belonged to family members and were excellent cars.
Not to say anything domestic from the late 80's - the 90's were bad. We also had an 89 LeSabre top out at 175,000, and my current 96 Town Car is rolling along at 165,000, and still runs like new.
25th Feb 2013, 16:47
You do not have to change out anything on the brake system. The diesel brake system is ran by the power steering pump. Bolt the original power steering pump to the gas engine, and you're good to go with no problems.