No heat as I go faster?


Old 12-02-06, 09:22 PM
Thread Starter
Join Date: Dec 2006
Posts: 1
Unhappy No heat as I go faster?

Hi Everyone,

I've read several threads about having no heat, but couldn't find an answer to fit my question.

I have a 99 Cavalier. I have heat fine - if I stay under about 35 mph. When I travel over that (and I travel about 55-60 mph on the highways), my engine shows it is cooling all the way down - and I mean all the way - pretty much past the cold mark (as if my car had been turned off), and the air blows cold. When I slow down again, my engine shows that it is warming up, and I have heat once more. My car runs absolutely fine otherwise.

Please help if you can - I live in WI and have to travel quite a ways to and from work and it gets QUITE chilly
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Old 12-03-06, 12:25 AM
Join Date: Jul 2006
Posts: 14
How cold is it outside? I'm assuming, since you're in WI, that it's quite cold. As always, check the coolant level and antifreeze concentration (auto parts stores sell a 'hydrometer'- looks like an eyedropper with beads in it for testing antifreeze). It could be freezing up and limiting coolant flow, or the thermostat could be stuck open causing the coolant to flow through the radiator when cold. Hope this helps.
Old 12-03-06, 11:35 AM
Join Date: May 2006
Location: Iowa!!!!!
Posts: 3,740
I would vote for thermostat, too.. The engine never warms to the point on turning on the electric fans to the radiator. The coolant would flow freely through the radiator. Under 35 the air flow through the radiator would be minimal and the coolant would warm up and give you some heat. Over 35 the natural air flow would cool the coolant in the radiator quickly and you'd have nothing.

I would change the thermostat.

Hope this helps,

Old 12-03-06, 12:57 PM
Join Date: Nov 2001
Location: North Texas
Posts: 2,345
I concur

Thermosat stuck open. probbably takes a long time to warm up. Replace the thing and your gas mileage will even go up as you are probbably running in open loop.

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