1974 Plymouth Valiant 225 slant six

Summary:

Reliable but thirsty

Faults:

New radiator cap.

Tightened up loose radiator hose.

Tune up.

Battery.

General Comments:

I bought this car from the original owner. It had been sitting in a garage since 1996. I bought the car late December of 2011. Amazingly the car started right up after replacing the dead battery. I filled up the gas tank, aired up the tires, topped off all the fluids, and drove it 45 miles home. A tune up and some general tinkering brought the car up to snuff. Mechanical parts are very cheap and readily available, which is a huge plus.

It rides and handles about as well as I'd expect for a 70s car sitting on ancient bias ply tires. The manual steering takes very little effort, even at a dead stop. The car accelerates adequately, although it won't win any races. Brakes are good for all drum manual units, although there is some pull.

It has been reliable, although for a small six cylinder, the fuel mileage has not been very good. I expected 20-22 mpg, but the car averages 15-17 mpg in country driving. Also it pings badly on anything but premium fuel, which makes driving the car any sort of distance costly. I've retarded the timing, which has helped. Also mildly annoying is the lack of hydraulic lifters. I'm baffled why Mopar went with mechanical lifters, when all the other major manufacturers had hydraulic lifters. As such, it's a loud engine; perhaps a valve adjustment will quiet it down.

The interior is plain, which I like. The bench seats are comfortable. Generally the quality seems to be pretty good. Underneath the hood, the Valiant is very easy to work on.

Generally I like the car, but the fuel mileage means that it'll be up for sale before too long. I have to go long distances to work that doesn't pay very much. It really hurts the wallet when my car guzzles up a third to half a day's wages.

Would you buy another car from this manufacturer? Yes

Review Date: 6th February, 2012

10th Feb 2012, 00:14

Be sure to replace those ancient bias ply tires, so you can be safe on the road.

10th Feb 2012, 17:29

You are right, a Slant 6 should get better than 15-17 mpg. I agree that you should be expecting 20-22 mpg, maybe even higher on the highway.

If you've really done nothing to it but change the battery, a tune-up could be in order -- plugs, wires, cap and rotor, air filter, oil change, fuel filter. And yes, check that timing. Knocking the timing back may have solved the pinging, but could also be negatively affecting gas mileage. Make sure the timing is correct to start with.

I had a '64 Dodge with a Slant 6, and my family had several Plymouth Volarès with the Slant 6, and they all ran on the "regular" lower octane fuel without pinging. You might have some carbon buildup in the head, which has increased the compression ratio.

Also, an old, carbureted car like this is a lot more sensitive to driving habits, so if you put your foot on it, gas mileage will suffer more proportionately than modern cars that have a computer to compensate for it.

Anyway, it is fun to still hear stories like this about finding a '74 Valiant in a barn, and starting it up to drive home.

In reply to 10th Feb 2012, 17:29

21st Dec 2012, 06:10

My name is John. My Valiant gets 28 MPG city, but stock it's got 20-22. You can contact me at jsmackiv@yahoo.com. Put 1972 Plymouth in the subject.

1974 Plymouth Valiant Brougham 4dr Sedan 225 CI Slant Six

Summary:

An all around well appointed and balanced car, that is reliable and adequate for most purposes

Faults:

Driver's side front three point seat belt actuator failed, not allowing the belt to be drawn out of the retractors.

Fuel gauge failed at 27,000 miles; would not register any fuel level.

General Comments:

This year Valiant was built on the longer Dodge Dart platform, which with torsion bar suspension, allows the car to drive and ride like a much bigger car.

Interior space seems cramped, even with the seat moved all the way to the rear most position. The driver feels as though they are sitting too close to the steering wheel.

Visibility is good to excellent.

Interior appointments are almost luxurious, with the padded door panels and a sensible application of faux woodgrain appointments to the dash, steering wheel center, and insets on the door pulls.

The exterior has the right amount of bright work, and is accented with tape stripes and a very nice hood ornament and rear finish panel.

Wheel covers are boring, and are not in keeping with the other appearance upgrades.

As mentioned (Supra), the Valiant rides well, but is not as nimble as one would expect. The front suspension is soft and allows the car to dive into a turn, even with new shock absorbers. In comparison to modern automobiles, it handles like a porpoise with heartburn, but is as good as most cars of that era.

Fuel economy is fair to good for a 3600 lb car, with results of as much as 24 MPG on the highway, and as little as 15 in town, yielding an average of about 18 MPG.

Performance wise, it is adequate on power, so long as you are not trying to win any races.

The slant six is a wonderful power plant, and goes forever without major repair.

My Valiant is a 30,000 mile original with only general maintenance performed from new.

The only noticeable problem is evidence of oil getting past the valve seals when the engine is cold. One can detect the slight odor of burning oil until the engine reaches operating temperature.

Would you buy another car from this manufacturer? Yes

Review Date: 20th March, 2011

21st Mar 2011, 10:13

"The only noticeable problem is evidence of oil getting past the valve seals when the engine is cold. One can detect the slight odor of burning oil until the engine reaches operating temperature."

My '85 Suburban used to do that. The unfortunate thing is that no matter how well cared for a vehicle is, seals dry rot.

Your car sounds like a polished gem. Could you please post some photos of it somewhere? Thanks.

21st Mar 2011, 14:56

A little valve guide puff isn't nothing, hell most show cars do that because they're not driven enough to keep the guides from rotting. I would use a ZDDP additive in the oil to keep the cam from going flat in a car that old.

It was nice reading a review about something different than a 10 year old Toyota too.

21st Mar 2011, 18:08

Canadian Valiants suffered from the following... all because of accelerated rusting caused by road salt.

(1) No adjustment possible of the front end alignment.

(2) The torsion bar mount across the floor at the floor area under the driver/passenger seat would rust away, allowing the bar to twist to a non loaded position.

(3) The front fenders rust through above the headlights.

Unless you are in a dry climate with your car, you would be wise to have it oil sprayed to save your gem... or at least those areas before the rust gets in there.