LED lights can interfere with radio signal

Dear Car Talk:

My husband installed LED lights in our 2012 Chevy Malibu LTZ. Since then, the radio signal has been awful! Even some of the 50,000-watt stations don't come in very well anymore. My favorite radio station is mostly static, and cuts in and out so much that it makes me miserable. I have even taken to driving our 2002 Chevy Suburban with the crappy radio. He says it's the station's fault, but it started when he changed out the lights. What did he do, and what does he need to do to fix it? Any more misery on my part and I'm setting the flying monkeys on him. Can you help? – Kathy

RAY: Oh, it's definitely your hubby's fault, Kathy. But you already knew that.

I’m guessing that the power source for the cheap, poorly shielded LED lights your husband bought probably is creating some radio frequency interference that’s being picked up by the car’s radio antenna. The most surefire way to solve that is to rip out the LED lights and leave them on his side of the bed, with a note that says, “Hope you saved the old lights, Fred.”

But before you resort to that, he should try to find a dedicated car stereo shop that does nothing but install and upgrade automotive sound systems. Having dealt with their share of irate customers, I’m sure they’ll have some ideas about whether the offending parts can be successfully shielded, and if so, how.

We spoke to our car stereo go-to guy, Jim Cavanaugh of Sound in Motion in Boston. He agrees that the cheap LED kit is what’s causing the problem. He says your husband can try something called a CAN Bus, which is a filter you install between the car’s light connection and the headlight kit. It might help, but just as likely, it won’t. However, at only $20, it’s worth a shot.

When the CAN Bus doesn’t help, he’ll have to remove those cheap LEDs and either reinstall your old halogens, or invest in a higher-quality, properly shielded LED light kit. Jim says he’s had good success with LED kits from PIAA, Race Sport and Putco, if you want some suggestions.

In the meantime, you can keep driving the Suburban, Kathy, or look on Craigslist for a 1981 Sony Walkman. Good luck.

Coolant warning light may indicate small leak

Dear Car Talk:

I have a 2016 Volvo XC60. When going to start the car yesterday, a "low coolant, stop engine" warning came on the dash. I opened the hood and checked, and indeed the coolant level was about an inch below the "MIN" line. We filled the coolant, and the warning on the dashboard went away. But now I am concerned that there is a coolant leak somewhere, even though I haven't noticed any puddles under my car. The car is under warranty, and when I called the dealer, he seemed unconcerned. He said this is something that's expected and happens in the fall because of the change in temperature, and also because the coolant sensor is really high in the reservoir, so it thinks the coolant is low when it really isn't very low. He said to just top it off and not worry about it. Is there really a phenomenon of coolant "contracting" in cold weather that would explain the low level of coolant that I clearly saw? I have never experienced this with any other car, and I am finding it hard to believe. What do you think? – Lisa

RAY: Well, things do contract when they get cold, Lisa, ask any guy you know who's ever gone swimming in the ocean. But I don't think the coolant would contract enough for you to lose an inch of it all at once in the overflow tank.

It’s possible that you were right on the edge, and a drop in temperature put the level just below the sensor. But I think it’s more likely that you are slowly leaking some coolant somewhere.

The most likely scenario is that you have one or more loose hose clamps, or something simple like that. I’d make an appointment with the dealer and tell him you want him to pressurize your cooling system, keep the car overnight and check it for leaks.

What we do is we’ll park a car in an area of the garage where we know the floor is dry. Then we’ll pressurize the cooling system with the cooling system tester, and run the engine until it’s good and hot. Then we’ll turn off the engine and let the car sit overnight with the cooling system still pressurized at about 15 psi. And if there is an external leak, we’ll see it on the floor the next morning.

Then, if you run your hand along the underside of the cooling hoses, inevitably you’ll feel coolant in one or two spots, usually near some hose clamps. We’ll tighten up those clamps, and that solves the problem.

Small coolant leaks like this are pretty common, Lisa. And the fact that you topped it off and it’s been fine for a while suggests that if there is a leak, it’s a very small and slow one, not one that’s going to cause a catastrophic failure while you’re waiting for your appointment at the dealership. And if we and the dealer are both wrong, hey, it’s under warranty!

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