Dear Car Talk:

I have a 2003 4Runner with about 150,000 miles on it. I bought this vehicle used about a year ago. It looks great, and has been a great, dependable car so far. Toward the end of the winter, however, I started having issues with the power steering. Then it completely failed. My mechanic told me that I'd need to replace the rack and pinion. So I started saving up for the repair, and lo and behold, the power steering went back to normal, even after driving for extended periods of time. Needless to say, I would like to save the cash for other things. Did it fix itself? What could explain why it failed and now seems fine again?

-- Luis

The weather. Failing steering racks are famous for misbehaving just like this in colder weather.

Perhaps you're too young to remember the great Rack-and-Pinion Epidemic of the 1980s. It hit GM cars particularly hard, so we know the symptoms well.

In cold weather, things shrink. See the "Seinfeld" "shrinkage" episode if you need any further elucidation on that.

Back in the '80s, GM's problem was that certain seals inside the rack would shrink in colder weather. And when they shrank, they'd allow power-steering fluid to sneak by them, causing a loss of pressure. That caused the power steering to fail, sometimes only in one direction. The only solution was a new rack.

The symptoms were always worse when the weather was cold. And they tended to go away after the car was driven for a while, because everything heated up under the hood.

I don't know if those same seals are causing your problem, Luis. It could be one of the valves, too. Or something else. But if your mechanic investigated and says you need a new rack, he's probably right.

And based on historic temperature ranges, I'd say you have until around Columbus Day to save up a thousand bucks or so. Good luck.