How much should my HEATER affect Engine TEMP?

I know that turning ON the interior HEAT will obviously cool down your engine, because it's blowing hot air off the engine itself, but how much is too much?

I usually wait until my digital dash is showing the engine temperature to be at 1/4 before I turn my interior Heater ON, but about 10 minutes after having my Heater ON, the damn engine temp has dropped so much that the air coming out of the vents is barely luke-warm. It's even worse if I'm doing a lot of steady, higher speed driving, the engine temp just keeps dropping. I've seen my digital dash temperature gauge go from 5 bars to just 1 bar in less than 10 minutes of driving after I turned the Heater ON.

Now, I always turn the Heater ON full blast, at the highest temperature, so I know that might make it worse, but still.

I hooked-up my Scanner to see what my ECM was reading and I saw the temperature drop from about 185 to 160 degrees in about 10 minutes!

Is this normal?

It's kind of annoying because of the affect that engine temperature has on my idle. For example, today, with the outside temp right around freezing, I start the car, and it idles at about 900-1000 RPMs. About

15 minutes of driving, it drops to about 650-700 RPMs. Then, I turn my Heater ON for about 10 minutes, turn it OFF, and now my engine is back to idling at 1000 RPMs!

This could be completely normal, but I don't remember in the past 3 winters having my interior Heater affecting my engine temperature so drastically!?

Anyone have any input?

THANKS!:)

Reply to
OldsFan4Ever
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Sounds like you need a new thermostat.

Regards,

Ed White

OldsFan4Ever wrote:

Reply to
C. E. White

Sounds like a thermostat just disappeared or stuck open. Aftermarket brands gave me lots of trouble. Three of them installed and all three did not work - they all stuck open after a week. It states `lifetime warrantee.` Skeptical, I now rely on OEM brands, all work reliably up to 5 years. Rick

Reply to
Ricky Spartacus

Sounds like your thermostat is stuck open slightly so that the radiator is always dumping a little heat as well as the heater. The thermostat should be able to close completely, and if it does so the heater should be able to keep you plenty warm under any ambient temperature south of Fairbanks.

Reply to
Steve

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