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MG Midget and Sprite Technical - airlock in coolant

I have a 71 with 1275 and I just replace the head gasket (again), bought a good one this time.
Anyway I think I have a airlock in the coolant. The temp gauge is not registering. Once the car cools off I am going to check the sender with some hot water to make sure its working but my question is:

If I do have a airlock what is the best way to resolve the issue.

Thanks
Ken Bargeron

given the temp gauge goes into the head just below the thermostat and right next to the top hose I'd say it's impossible to have an airlock in there that affects the temp reading. In the heater maybe, but not in the head itself.
David Smith

these little engines are notorise for air locks when you change out the coolent

take the plug out of the radiator where the coolent goes in and make sure its filled with coolent then start the engine and let it run for about 20 minutes at idle stay close and watch for over heating..most likely it wont.

Next put the plug back in the radiator and run another 20 minutes and stay close and watch the gauge for over heating... if it does over heat (most likely it wont) then shut it down and let it cool completely and redo step one...

if the temp stays in range after the radiator plug was put back in and ran for 20 minutes, then shut the car down and cool for 20 minutes then re-start it and take it for a test drive... if no issues after 20 minute drive , your fine...

just remember to re-tighten all your hose clamps after about 50 to 100 miles esp. if the hoses are new or you will have leaking


Prop
Prop

I used to fill the cooling system from the top hose on the heater:

- replace the radiator cap when coolant is just about to flood out
- put the hose back when coolant starts to flow from the exposed heater matrix pipe.

But first, as David implies, check your gauge by putting the bulb into boiling water...

A
Anthony Cutler

This thread was discussed on 25/06/2010

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