1975 Buick LeSabre Custom Convertible from North America - Comments

Alternator failure at 137k miles.

Radiator failure at 137k miles due to no maintenance/use.

Valve cover gaskets and rear engine seal failure at 137k miles.

Rubber body filler panels were intact but cracked/weakened; had to be upgraded with fiberglass kits.

Front seat seams failed, causing the vinyl to separate.

Door, window, and trunk seals failed due to old age and lack of maintenance.

Rear wheel seals began leaking onto brakes at 138k miles.

Fuel tank failed at 139k miles due to age.

This was the last year that Buick made convertibles in the 1970s. These could be ordered with similar options to the Buick Electras, and looked very similar from the front and sides. The engines were notoriously smooth-running and relatively trouble-free according to other owners and mechanics.

The 350-cubic-inch engine was too small for this size of automobile by 1975 due to a drop in horsepower. This drop came from emissions equipment retro-fitted to the design of this motor in the early '70s. In comparison to the 455 engine, the 350s took much longer to reach 0 to 60 miles per hour. Accelerating onto an interstate or passing on a 2-way road was mediocre at best.

Fuel economy is an issue with my 1975 LeSabre Custom Convertible. It averages between 9 and 10 miles per gallon. The drivetrain ratios were not improved until 1976, and it seems like the car's 3-speed automatic should pop into another upper gear by 42 miles per hour.

Engines and transmissions were smooth and quiet from the passenger area. The seats were covered in vinyl, supported with wire and foam, and were comfortable for drivers and passengers alike. Parallel and perpendicular parking is easier than expected, as the steering was more responsive and easier than the smaller GM cars of the 1980s and 1990s.

The rear bumper and area under the license plate were surrounded by rubber body panels, supposedly designed to reduce impact and damage in a rear-end collision. This rubber did not weather well and was cheaply constructed. On these two-door convertibles, the door pins were too weak for the weight and caused the doors to sag. This made it tough to open and close the doors properly. Inside, courtesy lights were mounted behind the doors, but were covered with brittle plastic lenses that did not hold up well to the normal heat of the light bulbs.

Beyond the seats, the interiors of the 1975 LeSabre Custom Convertibles are comfortable over-all. The crank windows work with little effort. The interiors have padded arm rests around the seat edges. There are plenty of ashtrays and lighters for smokers or charging cellphones. Legroom is comfortable for passengers with 34-inch or shorter inseams. While the dashboard and instrument panel was tastefully trimmed, the rest of the interior was rather plain.

The convertible roof is joined to the windshield frame with two large latches. The roof is lowered with the slide of an electric switch to the left of the steering column. These switches could stick, causing the battery to drain. The roof design works well, but the cross-members tend to rattle when the top is up. As with other convertibles, the roofs break down due to age, abuse, or neglect. It costs over $1000 to replace these large roofs.

Overall, the 1975 LeSabre Custom Convertible is a comfortable car for driving or riding, and is best-suited for driving in town or through the country. Due to the inefficient powertrain design up to 1975, and because of the lowered horsepower from emmision control devices, these aren't best-suited for highway or interstate driving.

Interesting observation about the lighters. Back in the 70's-80's all the "luxury" sedans had an ashtray and lighter in each door, so if the car was occupied by four smokers who all decided they needed to smoke at the same time, god forbid they would have to share a lighter or an ashtray.

Now most new cars do not come with an ashtray at all, at least as standard equipment. Apparently someone realized that the majority of smokers thoughtlessly fling their butts out the window anyway, so why bother putting an ashtray in there?