its been getting really cold here recently, and im pretty religious about letting my car warm up..i get out of work last night, start her up, arm the alarm and head back into my store to finish up a bit..after about 10 minutes, i get in my car.

the temp needle is about 1/4 of the way from the C to normal operating temp. i put the heat on, and noticed the needle drop back down to C. this is the first "boosted winter"...possible air in the coolant system? or was it just that cold out...

 

its ok man, chill out, literally. Once you turn heat on, the blower and blower motor are filled with coolant and the blower cools the coolant once it is turned ON, so you get extra cooling when the heater is on, no matter what the season is. and thus cooling your coolant more then it was, making the needle do lower as it is cold as expletive out.

My car does this even after drivign sometimes for 30 mins, if i make a hard boost pull, the gauge will go down quite a bit as i have a low temp thermostat, fal fan and a rowdy *** radiator

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by yehiknowrite &raquo;</TD></TR><TR><TD CLASS="quote">the temp needle is about 1/4 of the way from the C to normal operating temp. i put the heat on, and noticed the needle drop back down to C. this is the first "boosted winter"...possible air in the coolant system? or was it just that cold out...

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Yup the heater system in the cabin uses engine coolant. Not sure exactly how, but wade's description is probably correct. This is actually useful if your car starts to overheat. Back when I had my RX-7 I ran to AC for too long on one summer day and the car started to overheat (bad news on an RX-7). To take care of that turned off the AC and put the heat on full blast. This along with a trip to the car wash and a pressure hose pointed directly at the radiator helped to lower temps down. Also back when I was tuning my turbo CRX/B18C it started to overheat so I cranked up the heater and it lowered temps a little bit.

 

You shouldnt warm up the car by idling it, you should drive "normally" to warm it up.

 

How could you NOT know this is normal? You've never noticed this on any car ever before? The heater core is like a second mini radiator.