THE 1986 PEUGEOT 505 Turbo is the best of fair-weather friends. Actually, it's pretty darned good in rainy weather, too. But, golly, don't let it snow. And if it does snow, pray that it isn't that wet, heavy, slippery stuff.

The rear-wheel-drive 505 Turbo -- powerful, poised and impressive on dry and rain-wet roads -- becomes an absolute wimp in icy mush.

It slips and slides, even with moderate acceleration. Trying to get up wet-snow-covered hills qualifies the driver for membership in the Don Quixote League.

Bad tires? Unh, unh. The test model rolls on 15-inch, Michelin MXV all-weather radials, among the best on the market.

A bad rap on an otherwise splendid car? I don't think so.

A front-wheel-drive, 1986 Honda Prelude Si equipped with 13-inch versions of the same Michelin tires maneuvered through the same mess and made it up the same hills with little trouble. Egads! A 1981, front-wheel-drive, Chevrolet Citation equipped with all-weather Goodyear Vector tires, with 15,000 miles worth of wear, also outperformed the 505 Turbo on the same treacherous roads.

Outstanding complaints: Wet-snow handling. After being seduced by the power and grace of the 505 Turbo in other conditions, I just wasn't ready for the terrific letdown in the mush.

Also: When is Peugeot going to put a heat shield underneath the hood of its turbocharged cars? Turbochargers, which increase pressure on the air-fuel mixture in cylinders to boost engine power, also generate lots of heat. In the 505 Turbo, that will produce enough heat to eventually degrade the paint finish on the unprotected hood.

Peugeot's competitors put heat shields underneath their hoods. Why can't Peugeot do the same?

Outstanding praise: A simply beautiful machine on dry and rain-wet roads. Under these conditions, the 505 Turbo handles with a confidence and dignity that match and, in some cases, surpass those of its more expensive rivals.

Acceleration from the car's 2.2-liter, 4-cylinder, gasoline engine is breathtaking. It really zooms.

The overall craftsmanship of this five- passenger car is excellent. The optional, luxurious, leather-bound interior gets kudos.

And, too, let us sing praises to the 505 Turbo's automatic climate-control system: It is accurate and efficient.

Head-turning quotient: Classic European elegance.

Sound system: Six-speaker, AM/FM stereo cassette by Alpine. Always among the best, and it lives up to its heritage in this car.

Mileage: About 21 to the gallon, combined city-highway, running driver only and with winter climate-control system operating most of the time. Mileage might have been affected by long idling in standstill traffic and by the slippery, fuel-wasting shenanigans in the mush. Other factors affecting fuel consumption in the test model are its weight, 3,220 pounds, and its four-speed automatic transmission.

Price-as-tested: $20,325, including $675 for the leather interior and $375 destination charge.