Dashboard light is clue to condition of air bags
Volvo, which is known for its leadership in safety, originally told its customers to have their air bags replaced after 10 years. But based on its real-world experience, it later changed that to 20 years.
Q
My 1995 Honda Prelude has
warning labels that say the car’s two air bags need to be inspected after 10 years. Well, it’s almost 10 years later. Is this really needed? Or was this a warning that was put in before air bags were really understood?
Seth ARAY:
Well, there’s no way
to really test the air bag, other than to loan the car to my brother for the weekend.
TOM: Right. Without what is called a ‘‘destructive test’’ (actually setting it off and seeing if it works), there’s no way to know
off. That tells you the wires are
connected and the sensors are
working, and the air bag is ready
to go. It also tells you that your
SRS light works — which is important.
RAY: If the light doesn’t come
on, fails to go off or flashes while
you drive, then you need to see
your mechanic.
TOM: The other part of the
inspection is just a visual check
of the vinyl covering of the air
bags. If you see any cracks or for certain that the air-bag material
damage, that might hinder the and the explosive charge
operation of the air bag, too. are still in perfect condition. But
RAY: Or if you see a deep imprint based on industry experience, of a face in the vinyl, that we know that they’re likely to be
would suggest that the bag fine for the life of the car.
hasn’t been working as well as it
RAY: Volvo, which is known should. But I suspect you’ll find for its leadership in safety, originally
that it’s all fine, Seth. told its customers to have
Q their air bags replaced after 10
I have a ’93 Honda Accord years, just to be safe. But based
with 170,000 miles. There’s on its real-world experience, it
a general consensus from various later changed that recommendation mechanics that the car’s to 15 years, and now —
motor mounts are broken, or at with even more experience — to
least in a state of disrepair. 20 years.
Where I can’t seem to find
TOM: They’ve had Volvos consensus is in how bad this is. with air bags sitting out in the
Some mechanics have told me desert for 20 years, with the explosive
that it can cause irreparable chemicals just baking in
harm to the motor if I keep driving the sun. And every time they like this. Other mechanics — test the air bags, they still work.
sometimes at the same garage
RAY: The electronic components — say that while a nuisance, bad of the system, however,
motor mounts are not a critical can be checked. That’s something
problem as long as I don’t mind you don’t need the dealer
the car vibrating while at idle. for. The air-bag system has a
What do you say? self-diagnostic mode that checks
Brian
ARAY: all of its circuits every time you
Well, we should explain start the car. what the motor
TOM: So if you go out to your mounts are. They are the devices car and turn the key to the that hold the motor in place ‘‘run’’ position ( just before it
and attach it to the frame of the cranks), you should see an
car. The exterior sleeve of the ‘‘SRS’’ (supplemental restraint
motor mount is made of metal, system) light appear on your
but inside, they use rubber or dashboard. It should stay on for
sometimes, now, hydraulic fluid about six seconds, and then go
to ‘‘isolate’’ the engine and keep the engine’s vibrations from shaking everything else in the car — like your teeth.
TOM: But the vast majority of motor mounts are designed so that even if the rubber isolating component fails, the mounts will continue to do their most important job: keeping the engine from falling out on the road.
RAY: So, are you in danger of looking in the rearview mirror and seeing your engine tumbling off to the side of the road? No.
TOM: But there is some real danger in driving around with a bad motor mount. First of all, you put additional stress on the other motor mounts. If one is not doing its job, you risk ruining the other three fairly quickly.
RAY: And when the engine is allowed to move around and twist inside the engine compartment, you take the risk of shifting the geometry enough to bind up other components, like an accelerator cable, for example. That could lead to real trouble.
TOM: So we’re going to suggest that you go against all of your deepest instincts, Brian, and spend money to replace the bad motor mounts.
RAY: We know you’re a cheapskate, Brian — not only because you have a car with 170,000 miles, but because you’ve pestered a hundred mechanics for their opinion on your car, without ever paying any of them to fix it. You’re the reason they invented those signs that say ‘‘Insurance Regulations Prohibit Customers From Entering Work Area — Without a Valid Credit Card.’’ Write Click and Clack via www.cartalk.com or Car Talk Plaza, Box 3500, Harvard Square, Cambridge, MA 02238.