Car Talk
By Tom and Ray Magliozzi
Choosing a Floor Jack
Dear Tom and Ray:
I am looking for a floor jack for my personal use and need some advice on how big a jack I need to get. I know that a two-ton jack would be plenty to work on a regular car -- e.g., a Civic, Altima, etc. However, we also happen to own a Chevy Suburban with a gross vehicle weight of 7,000 pounds. I tried calling some shops and was told by some that a one-and-a-half- or two-ton jack would be enough, since the jack will not be lifting the whole truck. But there were some that said I need to get a jack that is big enough to hold the whole weight of the truck, which would be more like three or three and a half tons. What do you recommend? If I have to get a three-and-a-half-ton behemoth, I probably would not bother working on the Suburban on my own. If I plan to work on trucks and SUVs in the future, do I need to get a jack with a higher range?
-- Isao
TOM: Yes, you do. Our rule of thumb is that a floor jack needs to be rated for at least three-quarters of a vehicle's gross weight. So, according to our rule, a one-and-a-half-ton (3,000-pound) jack could lift a car that weighs as much as 4,000 pounds -- or two mothers-in-law.
RAY: So, if you want to work on your 7,000-pound Suburban, you'll need to get a three-ton jack, Isao.
TOM: Here's why: It's true that a floor jack does not have to lift all of the car's weight. It has to lift half of it -- taking two wheels off the ground. But when you operate at the limit of the jack's ability, two things happen.
RAY: One is that it gets very hard to lift the car. But second, and more importantly, you leave no room for error. And unless the jack is absolutely, perfectly centered AND the weight of the car is perfectly centered (which you can't always count on), the jack's linkage bars can begin to distort under the maximum weight, causing the jack to flip and the car to come crashing down.
TOM: It's never good to operate anything at the absolute limit of its ability. For instance, some scientists say a man can go seven days without water in 90-degree heat, as long as he doesn't move. Does that mean we should all lie down and wait seven days between drinks?
RAY: Similarly, you don't want to be under a Chevy Suburban that's held up by a jack that's quavering at the limit of its abilities.
TOM: So, you have three choices, Isao. You can get a three-ton jack, or let someone who has one work on your Suburban. Or, alternatively, you can buy a set of properly rated ramps, and use those to get enough clearance to work under all of your cars.
Put Safety First when Choosing a Car
Dear Tom and Ray:
Am I safer in a bigger, older car that doesn't handle particularly well and has no new safety features (i.e., my '92 Volvo 940 sedan), or a newer compact car with side-curtain air bags that handles well and performs well in crash tests (i.e., a VW Jetta)? Does young but small trump big but old?
-- Ruby
RAY: So, you've got the hots for a new Jetta, huh, Ruby?
TOM: It's not an easy question to answer. There are a number of things that factor into a car's "safeness." Size is just one of them.
RAY: There's also design. Some cars are designed to better protect their occupants with crumple zones, passenger roll cages and reinforced door beams. Some cars add electronics, like dynamic stability control and anti-lock brakes. And then there are air bags: front, side, head and even knee bags.
TOM: And finally, there's active safety -- how well a car handles in emergency situations, to help you avoid an accident in the first place. So, size is an important factor, but it's only one factor.
RAY: In general, I'd have to say that newer cars tend to have more safety advantages than older cars. But your older Volvo might be an exception to this rule. Despite its lack of some of the modern electronics and additional air bags, it is a large car and was extremely well-designed to survive an accident. If you were comparing a '92 Chevy Lumina with a newer car, I'd give the nod to the newer car for safety. But the Volvos were pretty good, even back then.
TOM: So, it's a tough call, Ruby. We certainly would like to see you with ABS, as many air bags as a manufacturer will give you and even dynamic stability control, if you can get it. But you really have to look up the crash-test ratings of the particular car you're considering, because the results can differ dramatically -- even with similar-size cars with identical equipment. You can link to the ratings from our web site, a href="http://www.cartalk.com" target="new">cartalk.com.
Help for a Broken Spark Plug
Dear Tom and Ray:
Yesterday, my son broke off a spark plug in his 1989 Ford F-150 with a six-cylinder engine. It broke off flush with the hole. Egad! How do we get the rest of the spark plug out, and what other concerns must be kept in mind?
-- Dave
TOM: Well, it depends on how he broke it, Dave. If he broke it by turning the wrench the wrong way (trying to tighten it instead of loosen it), then you might be in luck.
RAY: In that case, you would use an extractor -- something like Easy-Out -- which taps into the remaining piece of spark plug and grabs onto it with sharp, fluted edges. Once the extractor is attached, you simply put your socket wrench on the end of it, unscrew it in the proper direction, and the whole thing should walk right out.
TOM: If, on the other hand, it broke because it was rusted and fused in there, and he had the 7-foot ratchet extension on it and was walking around the car trying to unscrew it, the job gets a lot harder.
RAY: If the plug broke despite the fact that you were unscrewing it the right way, then you have to drill it out. This is a job best left to professionals, Dave. It's not for the faint of heart -- or the faint of talent. A mistake here can cost you a cylinder head.
TOM: What a mechanic will do is drill out the broken piece of spark plug, along with the existing threads. The result will be a smooth hole that will be bigger than the old spark-plug hole. He'll then use a tool to cut new threads for an insert, and the spark plug will go into that insert. Then you'll be all set.
RAY: He'll also have to fish out all of the metal shavings that fall into the cylinder during this operation. We get most of them with a magnet. If you don't remove them, they could cause serious engine damage.
TOM: So, you have to start, Dave, by holding your kid's feet to the fire and finding out exactly what he was doing when the spark plug broke. He'll be embarrassed to admit it if he was turning the wrench the wrong way, but that will actually make his life a whole lot easier.
RAY: This is one of those rare cases where stupidity pays off.
TOM: Aha! I've been looking for cases like that.
Got a question about cars? Write to Click and Clack in care of this newspaper, or e-mail them by visiting the Car Talk Web site at cartalk.com.
Tom and Ray Magliozzi have done their Car Talk show for National Public Radio for 25 years. The show airs on WNJN 89.9 at 1pm on Saturday and 11pm on Sunday.
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