Details for Car talk Editorial Saturday

Pinging noises could Point to a bad knock sensor

Dear Car Talk:
I have a 2015 Kia Sportage with
25,000 miles on it that I purchased
new. At about 15,000 miles,
I noticed a slight ping when slowly
climbing hills. I tried changing gas,
to no avail. Then I noticed that
when I parked the car on a slight
hill, facing either up or down, I got
a loud noise for about a second or
two when I started the car. It sounds
like the bearings are starving for
oil. I made a recording of this and
took it to the dealer. They said it’s
a normal sound for newer vehicles.

Pinging and bearing noise is the
new normal? What’s the next stage
of normal — oil leaks and blue
smoke? What do you think?
— Dennis
That’s the old normal, Dennis. Cars
shouldn’t ping at all these days.
They all have knock sensors that
automatically adjust the timing
if you happen to get gasoline that
has too low of an octane rating. So
it’s possible you have a bad knock
sensor. But that would trigger a
check engine light, and you didn’t
mention that.
It also may be something other
than pinging that you’re hearing.
Try putting a tank of the highestoctane fuel you can find in the car.
If you still hear the noise at the same
intensity, then it’s not pinging, it’s
something else.
At that point, your dealer will need
to hear it to figure it out. It could
be a loose heat shield, or a loose or

broken exhaust manifold bolt. Or
almost anything.
As for the starting noises, car
engines, especially smaller ones, do
make more noise when they first
start up these days, usually as the
hydraulic lifters get pressurized. If
it goes away in less than 15 seconds
— which you say it does — I wouldn’t
worry too much about it, as long as
your oil level is correct.
But in any case, it’s good that you
reported it to the dealer, and that
it’s noted on your repair order. That
way, if it does get markedly worse
over time, and something really is
wrong, you’ll have a record that you
complained about it while the car
was under warranty.
The other thing you can do is ask to
drive a used, 2015 Sportage that the
dealer has on the lot. See if it makes
the same noises.

The dealer is telling you that,
essentially, “they all do that.” So
drive another 2015 and see for
yourself if they do.
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