Q45 cooling system

[rover3l]

Following a cooling system flush I have noticed that the heater is making a "bubling" noise. I assume it is an airlock issue. After reading the FSM I notice there is a procedure for opening the heater valve which should be done prior to a flush and I suspect the franchise I used did not do this. What would be the best way to remove the air from the system retrospectively?

[elwesso]

I have a gurgling noise from time to time in my heater.... No big deal.... Run with the heater core open for a while, and make sure the overflow res. is full...... If there's any excess air, it'll be pulled out by the vacuum, and it will top itself off..... But, to be safe, check it the next couple of days (by opening the radiator filler cap) and if its low, top it off.....

[Q451990]

The heater core isn't controled by a valve - it's always open - there's just a bypass door that keeps the air away when you don't want it. Best way to eliminate it is to top off the coolant after driving it for a while... sometimes you can "burp" a little air out by squeezing the radiator hose with the cap off.

Heath

[911/Q45]

I think there is a valve, hence the procedure to make sure it's open when flushing the coolant as specified in the FSM.

[maxnix]

My thoughts exactly.

[Q45tech]

The valve [really a restriction] doen't close completely like most cars so the valve [and heater core] never fails. No settling of sediment to stick the valve.

In the past, I used the no valve comment to avoid confusing owners who had no heat [door hinge failure is 100 times more common] and that is very very rare on 90-93.

Either way the entire dash has to be removed to get at either.

There is always some coolant flowing thru the core.