2007 6 4cyl no heat at idle
 

Been a loong time on here.. That means things have been working well.

I have a from new 2007 mazda 6 4 cyl... Have had no work done other than regular maintenance.. It is freaken cold here today -10 Celcius.. anyway, on the way home we noticed the heat would disappear when the car is at idle.. not over heating on the guage... eveything looks fine.. fan running fan.. soon as I take off or revv the engine the heat comes back instantly.. Wierdest thing.. I can't figure it out.

Anyway, I am going to check it for low fluid when it cools down - but wouldn't the engine have gotten overheated if that was the issue? or the waterpump? Why does a higher idle make the heat come back..

Anyone?

T

The waterpump speed is depending on the engine RPM.

You do the right thing checking on the fluid. I had a similar situation with wifie's Ford Contour and the coolant level was low, no overheating. I added coolant and everything was fine, noticed coolant going down again and added Bar's leak stop. While the coolant was low the heater worked inconsistantly.

If the coolant level is fine I would suspect a partially clogged heater core or a water pump on the way out.

Make sure the drive belt is a -o.k.

Sounds like u have some air in the system usually caused by being low or changing the coolant and not burping it.

Yeah, I have never touched the system from new. I did add about less than a quart of coolant last night and my wife took it to work today and she said it seemed better. However our cold snap has come to an end... It seems like the water pump might be on the way out. are they tough to replace?

T