Tell Me Again Why They're Called "Idiot Lights"...

Dear Car Talk

Dear Car Talk | Mar 14, 2013

Dear Tom and Ray:

I have a 2002 Subaru Impreza WRX wagon. Yesterday, while sitting in traffic, I noticed that my temperature gauge was all the way in the red. I glance at it occasionally (weekly), and this is the first time I've noticed a high temperature. I continued on to my destination, parked the car for about two hours, then drove the car home.

For the first three to five minutes, it was fine (below the middle mark), but then it slowly crept up, steadily but surely, to the RED HOT zone. It crept up there over the course of about 15-20 seconds. Any idea what would suddenly cause this? Thanks!

-- Travis

TOM: Maybe it's global warming, Travis.

RAY: Yeah, combined with a blown head gasket.

TOM: It's possible it was something cheap and simple, like a stuck thermostat. Notice I said "was" something cheap and simple. Because now it's probably complicated and expensive.

RAY: Because you kept driving, even when you knew the car was already overheating, you may have made it a lot worse.

TOM: If your original problem was a loose hose clamp, now it might be a blown head gasket or a cracked head.

RAY: So, what to do? Well, unless your mechanic is three minutes away or less, have the car towed to him, and ask him to take a look. He'll check for simple stuff first. If he doesn't see an external leak, he'll do a head gasket test and call you with his "I've got bad news for you" voice.

TOM: In the meantime, you can start working on your home equity loan application, just in case.

RAY: And next time, when you're tempted to "make it home, then figure out what's wrong," be aware that there are some circumstances when that approach will cost you thousands of dollars.

TOM: Two of those circumstances are when you see red idiot lights on your dashboard that say either "HOT" (or sometimes "COOLANT") or "OIL." When you see those, pull over, shut off the engine and call for help. Remember, Travis, they're called "idiot lights" for a reason.

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