It's just getting cold here in PA, and I just started using the heat this week. I noticed that when I start my car up when it's cold, there is a slight bubbling sound coming from the dash. If I rev the engine a little bit the bubbling seems to go away. I'm assuming this is air somewhere in the heater core. Is this a problem? Will it do damage? And do I have to flush the whole system, or is there a better way to get rid of the bubbles?

 

When car is !!!!COLD!!!!! remove the radiator cap. Check it, make sure it is good, if it is a couple years old replace it. Start the car, and add coolant.. continue to add until all the bubbles seem to be out.

Put the cap back on and refill the overflow bottle.

 

Wait, you mean to tell me that the car has to be cold!?! :eek3:
:chuckles:
Anyways, I had to put in a new rad and hoses last week, so it must have just had more air in it then I thought.

 

Problem fixed. I think it was a combination of two things: #1, I had filled up the overflow bottle, but it was empty after a 2 weeks of driving with the new rad, and #2, i hadn't bled the system long enough, and there were some more air bubbles.:hsdunno: So the sound is gone now. Thanks for the help

 

I had a small leak in the 2 coolant lines that run to the heater core... those dry out and crack as well.

 

Just remember when you bleed you need to have the heater on so the fluid goes through there too.