Astro van new heater core, air pocket

[Vinnie6]

I had to replace the heater core in my '02 Astro when the old one developed a leak. Now I have low heat. I have been through this before when I replaced coolant. The heater core in the astro van is higher than the rad cap. It is the highest point in the cooling system. Therefore it tends to trap air bubbles. At least it is summer now. Today I parked on the steep driveway and jacked up the front end to get the rad cap higher than the heater core and ran it 30 min. without the rad cap on. Afterwards I had pretty good heat again. It won't surprise me if I have to do that once or twice more, though. I wonder how they put these things together in the factory with no air bubbles! BTW I use Amsoil antifreeze 50/50 distilled water.

 

[oilboy123]

Try blasting around on the road like merging on a freeway etc. Worth a shot. Get maximum water pump flow.

 

[Chris142]

Rev it up in the driveway. It wont ever bleed if you let it sit and idle. 3000 rpm for a few seconds untill the stat opens should do it.

Cars are filled at the factory by vacuuming the cooling system then shooting coolant into them.

 

[George7941]

At least one of the supply or return hoses will be connected to the top of the core, so disconnecting this hose should enable you to get all the air out.

 

[Vinnie6]

Originally Posted By: Chris142
Cars are filled at the factory by vacuuming the cooling system then shooting coolant into them.


Aha!