Cooling System Air Bubbles

[Deleted User]
[Deleted User]
edited July 2012 in HUDSON
How long does it usually take to get the air bubbles out of the cooling system after it was drained, refilled and engine started again?

Comments

  • RL Chilton
    RL Chilton Administrator, Member
    Typically if you have bubbles in your coolant, you've got a blown head gasket.
  • [Deleted User]
    [Deleted User]
    Sorry, I need to be more clear.

    These are bubbles that may have been trapped in the block, passenger heater core or upper radiator hose caused by refilling a totally drained cooling system.

    Maybe using the term "trapped air pocket" would better describe it.
  • Matt1950
    Matt1950 Senior Contributor
    If you are running a Standard "vintage" Thermostat, with original equipment plumbing it typically takes three Engine Hot and Cold cycles. This is when the engine is ran above 1000 rpm to move the coolant.
    I run the engine with the cap loose at idle for the first cycle to "burp" it.
    Turn your heater on and confirm that hot air blowing or feel both lines and confirm they are both hot. Air likes to stay trapped in most heater cores. When coolant is aerated it needs lower rpms for the bubbles to find a high spot to disperse. High rpms have a tendancy to aggitate the coolant and the pump impeller will agrivate this condition specially when the engine is cold and the rpms are high.
  • [Deleted User]
    [Deleted User]
    Thanks, Matt.

    The heater core leaks (as I found out when I first started it) so I have the core bypassed until such time as I can remove it and get it repaired replaced along with the Ranco valve (just to be safe). I think I have it cleared now especially now that I know I had the system over filled and left no room for heat expansion.

    I am running a modern thermostat in a modified/plugged thermostat housing. A dog ear broke off my OEM housing. I went the modern route as it is not see by any judges and makes replacement a little easier (again just in case).
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