Heater Core Overheating???
 

I think my Heater core is over heating (not to sure)? Once in a while, I will drive to the store or to my parents house couple miles from my home in my '70 lwb and a bubbling sound will come from behind the dash on the passenger side. It doesn't happen all the time though, just sometimes. I'm thinking it's the heater core. What do I need to do/fix/replace in order for it to stop making that bubbling sound? Any help will be appreciated, thanks!

Re: Heater Core Overheating???
 

bubbling is air in the system... which means you are low on coolant!
When you fill it, it can take a while for all the air to work out of the system.

Re: Heater Core Overheating???
 

+1 Plus i'll bet that the pressure hose from the manafold or top of the waterpump ( not the side of the water pump ) is feeding to the top of the core and not the bottom.. Just a guess..