1981 Cadillac DeVille 6.0 V8-6-4 from North America


I never think there will be a better car than these RWD Cadillacs


The car hadn't been driven since 1989 so I had to fully service the engine and hoses; including the water pump, radiator, power steering system, and belts. One thing about this car is the belt system is extremely temperamental, it is best to get them changed by a professional that can gauge the tension. I went through the wiring harness and fixed and reconnected the V8-6-4 system.

General Comments:

These cars are great for daily drivers, they are comfortable to drive and extremely reliable when properly maintained. The V8-6-4 system is not as bad as they say, and the only bad comment I have about it is that going 70+ with it sucks, so I wired a shut off switch for those speeds.

This car had the rare posi-traction which made it excellent to drive in harsh northern winter conditions, I never got stuck.

If you smoke or have kids with phones to charge, this car is plentiful with cigarette lighters and ashtrays, one for every door.

Would you buy another car from this manufacturer? Yes

Review Date: 20th September, 2016

22nd Sep 2016, 03:44

The 368 6.0 was the last of the better Cadillac V8s.

24th Sep 2016, 07:39

Could you explain the V8-6-4 system. I am from the UK and not used to V8 configs. Is it V6 for cruising and V4 for around town? Thanks.

24th Sep 2016, 17:08

It was designed to run on 4 cylinders at highway speeds; it would gradually go from 8 to 6 to 4. However the system was problematic and many owners simply disconnected it.

1981 Cadillac DeVille De Ville Brougham 4.1 V8 from UK and Ireland


A surprisingly economical and tough glitz cruiser


This car was very strange because even though almost everything was broken on it, it ran reliably for two years.

Even the engine had a knock, and the self-leveling suspension wasn't working. The air condition and electronically controlled ventilation system were working according to the position of the moon and stars above, the electrical system was a zoo of gremlins, and a dead rat was mummified in the engine compartment, as I found out one day. Yet, it ran all very well.

General Comments:

The car was surprisingly economical, giving me about 28-30 mpg at all times.

It was underpowered, but the ride quality was good, and I came to like the combination of flashy looks and good economy a lot.

The interior illumination was 100% Hollywood and made getting into the car at night a festive event.

Overall, a good one would certainly be worth keeping.

Would you buy another car from this manufacturer? Yes

Review Date: 14th February, 2005

1981 Cadillac DeVille Coup 368 6.0 litre from North America


An outstanding achievement for Cadillac in 1981


The valve train and most of the oil galleries were plugged with sludge due to failure to change the oil. 14 16 valve push rods needed to be replaced as they were plugged solid. All valve lifters were replaced as well along with the camshaft. Timing components such as timing chain and gears were also replaced.

The water pump and radiator was replace just as insurance.

The lower end (oil pan) was checked for damage and none was found. The main and rod bearings were like new with very little wear. The oil pickup screen was also replaced.

The headliner was replaced due to factory glue failure.

General Comments:

The 368 (8-6-4) is the last of the cast iron blocks Cadillac produced. With proper maintenance, this engine will last forever. Most people complain about being underpowered, and this is true. But, once you get this baby up to cruising speed, she'll shift into 4 cylinder operation and give you 23 MPG all day long.

Would you buy another car from this manufacturer? Yes

Review Date: 17th December, 2003

1981 Cadillac DeVille Coupe 6.0 V-8 with 8-6-4 system from North America


A tough, well built luxury cruiser


The water pump failed and needed to be replaced. This was inexpensive and easy to do myself.

The air conditioning system didn't work. I never had this fixed though I later discovered that the fix would have been easy had I any knowledge of auto mechanics at the time.

Had a spark plug oil fouling problem which eventually cured itself for unknown reasons.

Trunk pulldown motor was wearing down when the car was sold.

The headliner was also sagging badly.

General Comments:

This car was built like a tank. I have no doubt that it is one of the most noble cars I will ever drive. It underwent a lot of abuse from previous owners including infrequent (if ever) fluid changes. Car still ran fine at 130,000 miles when I sold it.

Cadillac's notorious boatlike handling was not missing from this vehicle. It suffered from severe body roll in hard cornering, and pitched badly under acceleration and braking.

The 6 liter engine was torquey enough to haul the car around at a decent pace, but produced a neolithic specific output of 23hp per liter. This was no doubt mostly due to the archaic emission controls which strangled the engine. This hampered acceleration greatly.

The 8-6-4 cylinder deactivation system performed very well. This is apparently rare, and the system was plagued by problems in most cars which were so equipped. The system shut down the right amount of cylinders at the right times, and helped noticeably with fuel economy.

This car's features combined to make the driving experience incredibly comfortable. Leather covered most surfaces of the car. The front and rear bench seats were huge. The car had power everything imaginable. The 8-6-4 system, cruise control, and trip computer were well ahead of their time.

Overall, very well suited to its purpose as a luxury cruiser. I miss that car, but I don't miss how slow it was.

Would you buy another car from this manufacturer? Yes

Review Date: 8th August, 2001

27th Dec 2014, 08:26

Yep, sounds like a nice car, and the V8-6-4 is rare but it shouldn't be. It was plagued by a few things early on, including stalling, rough idle, and some suspicious oil valves. Most of these problems came from a computer supplied by an outside company; apparently there were 2 of them going around. According to a good friend, the myth that they were updating chips was merely a strategy used in the lawsuit brought over the cars.

26th Nov 2015, 21:30

V864 was a stopgap measure to meet CAFE standards for 1982. The 6.0, which is primarily an engine from 1968 with roots from 1949, is an undeniable gas guzzler. V864 was suppose to be a band-aid for the high fuel consumption, but obviously an unproven technology that caused frustrations for dealers and owners alike, and it didn't even meet 1982 CAFE standards - so it had to be dropped (except limos, which had the engine but curiously lacked the "MPG sentinel or "econo minder"(Canadian Models)). I doubt it ever ran right and some owners simply tolerated the annoying driveability.

If you own one, I'd say your best bet is to by-pass the system and run it as a full time V8 as that's what it is anyway. You'll have a good long lasting and smooth running engine that's far better than the sluggish and troublesome HT4100 or sluggish and thirsty Olds 307, which was still using a carburetor all the way up to 1990!!

11th Jun 2016, 18:40

I have a beautiful 81 Deville 8 6 4 with the override to V8. Powder blue, white leather with only 64,000 miles. I love this car; it looks and drives great. I get more looks and comments in this car than I do in my 67 Bonneville convertible.