Hello all

07 460 here with 130,000 miles
just last March I had new radiator, fluid and thermostat installed
I live in the desert SW USA so had no reason to turn the heat on until now
and now I have no heat at all

my mechanic tried to do a "flush" of the heating core and now I do have
heat but it is intermittent

can someone explain the heating core to me, how is it possible to flush it,
and how does it become plugged if that is a good term to use
possible it needs to be replaced, is this a big job and about how much $

THANK YOU for any comments to educate me

 

I suspect, you have an air pocket in the heater core. It is due to improper air purge. If it is caused by air trapped in the core, drive your car on ramps and stop the engine. Open the coolant overflow tank cap, make sure you have enough coolant in it the tank. Start the engine and let it run, watch for air bubbles in the tank. If see some, there is air in the cooling system.

 

Check the coolant overflow reservoir under the air inlet tube to see if it’s full or not.

 

If your mechanic did a proper flush he should have back flushed and forward flushed for a lack of a better term. Also if he bled it properly which should not be that hard to do and your heart is still intermittent then parts of the core could be plugged which is the very worse case scenario. Before you go down that route make sure that there is no air in the system. You can even raise the front of the car a little or bleed it with the car on an incline. This will make the reservoir the highest point in the cooking system which is important since air will try to escape at the highest point. Let's hope you don't have to change the heater core!!! Have you ever used any stop leak products in the cooling system?

 

A very important point in all this is the cap on the coolant reservoir. The cap is a pressurization cap, much like the old radiator caps and must be properly tightened or pressurization will not be attained and there will be overflow because the boiling point of the coolant will be lower. To properly tighten the cap, you must turn until it clicks, much like the pressurization cap on your fuel tank.