Hey guys/gals, so here is my issue. In the last two weeks I have been noticing some strange noises coming from the passenger side, under the dash.
To put it simply, it sounds like a coffee machine is finishing up a fresh pot under my dash.
Happens with the heater temp on hot or full cold.
At idle mostly.
Coolant level is good.
I tried burping the system by leaving the rad cap open half a turn, no change.
I was thinking a leaky heater core but fluid levels and lack of fog on the windshield and no coolant on the floor mats tells me no.
Without a pressure test I can't be positive.
I'm thinking I've got an air pocket up in the heater core that is not wanting to get out of there.
Anyone have a similar issue?
2001 Tundra
4.7
120,000 miles.
Thanks for the new frame Toyota!

 

My 97 LS400 and 99 Camry do same thing. Has to be air and would have to effect heating efficiency. I figured as long as they heat good and not making a mess...leave them alone.

 

thats normal. all vehicles will have a water boiling noise coming from the heater core. nothing to worry about.