Hi,
I've got a crackling / snapping / rattling sound coming from my heater core in my daily driver 85 Caprice 305. If I pinch off one of the heater hoses, the noise stops. The noise comes on acceleration, and at a slight rev in neutral. I can't hear it outside, looking at the engine. Too much noise.
Causes I can think of :
1) Steam is forming somehow in the cooling system, and I am hearing the old-fashioned steam radiator sound in the heater core. 2) Air bubbles are trapped in the heater core and are slapping around in there. 3) A piece of debris (metal? ) is flopping around in the htr core.Additional info : I do have a coolant leak at the rear of the intake manifold. I suppose air could be getting in there.
The car is an 85 Chevy Caprice. The heater core is only 3 years old.
Any ideas ?
Thanks,
L