Is this anything to worry about?

[gmrulz4u]

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!

[Intlcutlass]

Sounds like when you finally get up to temp, that the thermostat is opening early? , You haven't changed the stat or anything have you?

 

If it's cold around you that would play into the running temp as well.

[gmrulz4u]

My thermostat is about a year old, 3 months ago I had a completle Cooling System Flush and Fill done at a local shop.

 

I guess it's not really possible to have a cool engine AND hot air. I know most people would be happy having a nice cool engine, resulting in more power, but it totally sucks in cold weather when it take forever to def-frost windows etc.

 

In the summer everything was normal, the temp would get up to about 225-230 and then the cooling fans would kick ON and bring the temperature back down.

 

I don't know, I guess I'll just replace the t-stat...