Bubbling Noise

[mrnickleye]

Originally Posted by Poodles

Yeah, but jumping to the conclusion it's the HG is a bit hasty as he's smelling musty inside the car, which sounds like something else entirely. Also, from what I hear, the heater core is only turned off when your climate control is at 65.

Ok....my $0.02 of personal "experience". True, the water flows thru the heater core all the time, except at 65* on the controls. The guy said he was having issues of a 'pressure' buildup in the system. That comes from a BHG, just starting probably. Have it tested with a block test, or an emmisions test at the radiator cap. I fought mine off for 3 winter months, then did the hg/valve job before summer came.

Our cars run with pressure in the system. So....
Leaking hoses (or loose clamps) are called that for a reason...they leak ! There will be signs of coolant at the leak.

The only place I've ever seen that will cause the coolant to NOT return from the bottle is the radiator cap, due to a bad gasket...and the hose to the bottle not sealed good or cracked. Then air will be sucked back in instead of coolant. This part of the system is NOT under pressure, so signs of a leak won't always be there.