Advertisement

Dear Jim,

I drive a 1993 Ford Escort LX (L4, automatic) and the thermostat is stuck in the open position. I know these units don't cost very much, but a friend told me to just take it out completely rather than replace it. He says the car will cool off faster in the summer months without one in there at all. Is this true?

-- Chris Szymanski

I'll have to say, bro, your buddy's advice is a lot better for keeping us mechanics in business than it is for your Ford. Let's think this one through a bit.

He's saying that if the thermostat isn't there to restrict the flow of coolant to the engine (which it does), your engine will run at a lower temperature than it would otherwise.

Sounds reasonable at first, but the logic falls apart when you know a little more about what goes on under the hood.

Sure, coolant cools the engine, but in the process it also gets really hot. There's always the radiator there to cool it back down, of course, but thanks to those pesky laws of physics, this isn't something that happens instantly.

All that hot liquid needs to spend enough time in the fan-cooled radiator to actually lose all that excess heat it's picked up, before heading back to the engine for another cooling cycle.

See what I'm getting at? Without the thermostat -- the flow regulator -- in place, coolant gets to the engine faster, yes, but it also rushes through the radiator too fast to cool back down.

By the time it gets to the engine again, your coolant is already too hot to offer much relief, and your engine ends up running hotter because of it. That means overheating, cracked heads, blown gaskets and all that other nasty, expensive stuff we get so much of in the summer.

Replace that thermostat, brother.

If your Escort still isn't getting the cooling it needs, ask a knowledgeable parts person about alternative increased-flow-capacity thermostats of radiators that might fit your make and model.

Tip of the Week:

Spread the word, drivers: If you're having the air-conditioning system serviced on a pre-1994 vehicle, and the shop wants to recharge it with R-12 Freon, just say no. The newer "134a" stuff is a fraction of the cost per pound, doesn't eat the ozone layer, and in my experience gets your vehicle interior up to five degrees cooler than R-12.

Switching to 134a might mean a minor conversion job on your A/C system, but it's worth it in the end.

Buffalo Jim, owner of Allstate Auto & Marine Repair in Las Vegas, writes a weekly column. Send your automotive questions to him at buffalojim@lasvegasniftynickel.com. If Jim picks your question to answer in Nuts & Bolts, you'll also be the proud recipient of a deck of official Buffalo Jim playing cards, presented in a classy, tin box bearing his hairy image.