Drive it forever

Q. I have about 30 quarts of 10W-30 SF and SE oil that's close to 30 years old. Some of it is in metal cans, some in paper containers. The oil has been stored at between 65 and 85 degrees for all these years.

Would it be OK to use any of this oil in a 2001 vehicle?

A. No. The current crop of engine oils are rated SM by the American Petroleum Institute, an industry clearinghouse and standard-setting organization.

That SM rating is not related to the more commonly cited viscosity index. The car companies specify that an API-rated oil must be used in their vehicles to meet warranty requirements. The API rating is changed periodically to meet tighter, tougher performance requirements for lubricating oil.

There are a number of differences between your antique SE-rated and SF-rated oil and what's sold today, particularly in the amount of sludge accumulation and volatility that the newer oils allow. What's volatility? That means that the oil won't evaporate right out of the crankcase at the higher temperatures we see in today's engines.

Your 2001 car was engineered for SJ-rated oil. Fortunately SJ oil is compatible with older vehicles, and it's perfectly acceptable to use the current crop of SM-rated oil in any older vehicle. The SF-rated oil became obsolete in 1988, however, and the SE in 1979.

Furthermore, because the additives in the oil aren't necessarily stable, I wouldn't even use this old oil in a car of similar vintage.

Q. When I shake the front wheel on my 1993 Honda Civic, there is some movement. When I remove the wheel, I can move the brake disk in and out very slightly.

When I drive and turn to the right, there's a dull whirring noise. Is this the bearing or the CV joint?

A. It's the wheel bearing, almost certainly. Front-drive wheel bearings should never have any perceptible end play, and that's exactly what you're describing.

That rumble you hear is the play in the bearing, which could fail at almost any instant, either by freezing up, which is bad, or by coming apart, which is worse.

I suggest you get this car to a mechanic immediately.

Unlike the old-fashioned, tapered bearings used on the front wheels of rear-wheel-drive cars and the rear wheels of front-wheel-drive cars, these bearings are sealed, prelubed for life and not adjustable. They generally last the life of the vehicle, or several hundred miles after you whack a curb or pothole hard enough.

A failed CV joint generally makes a clicking noise going around slow corners, but won't cause any end play.

Q. I need to replace the ball joints and shock absorbers in my car. Which should I fix first to feel safe on the road? I am on a tight budget.

A. Do you want to feel safe or actually be safe?

Worn-out shocks and worn-out ball joints will make your car handle . . . oddly. Loose ball joints will create steering that feels vague, and the poor alignment will wear tires prematurely and increase understeer around corners.

Worn shocks will make the car wallow after any kind of vertical excursion, such as running over a pothole or a piece of debris.

You've seen those old cars bouncing endlessly on the freeway, right? Worn shocks.

In either case you'll have reduced control all the time, especially in emergencies, in which you might plow off the road instead of driving out of the sticky situation.

OK, I don't want to sound like your dad. So, if you really can't afford to replace everything at the same time, I'd do the ball joints first. At least, if the shocks fail altogether, they won't let the control arms fall off.

Mike Allen is a senior editor for Popular Mechanics magazine. Questions should be sent via e-mail to driveit@nytimes.com.