Cooling System

[ashley]

Good morning fellow Stag enthusiasts!

Can anyone give me some advice on the correct procedure for eliminating a suspected air lock ina Mk2stag cooling system? Your advice would be much appreciated, thank you.

Kind regards

Ashley

[DJT]

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Hi Ashley,

I assume you have a standard Mk2 system?

Is the air lock a result of something done recently? Such as drain/flush the system or change thermostat?

First off, if you have changed the thermostat, did you fit one with a bleed hole in the plate? If so, was it fitted so that this bleed hole was at the top? Also, the Mk2 has a thermostat with a 'foot' to shut off the by-pass. Similar to that shown here:

http://www.ldpart.co.uk/shop/shop.ph...5b6c3b89c54620

When you fill the system, remove both the overflow bottle pressure cap and the radiator filler plug. Jack up the front passenger side of the car to raise the filler plug as high as you can. Also check that the heater valve is open. These can stick so you need to check that it is obeying the dashboard control. The heater valve is above the driver's left foot.

Fill the system via the radiator plug until coolant starts to overflow into the bottle. With the bottle half full, replace the pressure cap. Continue to fill the radiator, squeezing the top hose to purge any air. When full, replace the filler plug.

Run the engine and check for leaks. As it heats up the overflow bottle level will rise. This should return to somewhere below half way when fully cold. Check again when cold and repeat as necessary to ensure all air is out.

Dave

[V8 Rumbler]

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Morning Ashley - Welcome to the Mad House

(Clearly DJT types faster than me)




Darren

[ashley]

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Thanks Dave,

I had to remove the radiator to replace the viscous fan coupling. The car is all back together and running but the heater is not blowing out any hot air so I have assumed an air lock. I realize it could be a faulty heater valve instead but not sure which is responsible? Could you advise some checks I can do to ascertain which one of the above items is creating the problem?

Kind regards,
Ashley.

[DJT]

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Ashley,

The heater valve is just above the driver's left foot. It is operated by a cable attached to the Hot/Cold slider. If the valve seizes the outer casing of the cable slips from its clip and, although the slider moves, the valve doesn't. If you look at the valve and move the slider you will see if it turns or not.

If it is stuck, then it has to be removed to service it. There are tips available on here if you use the search facility.

I assume now that the car cooling system is otherwise behaving itself and it is just a lack of hot air that is concerning you?

Dave

[jleyton]

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Hi Ashley, Welcome !

I bought myStag a couple of months ago and, like yours,the heater didn't work. First thing to do is to check thetwo heater hoses under the bonnet as they enter the bulkhead. In my case they were hot which pointed to a heater valve problem rather than engine or air lock.

Luckily for me, my heater valve wasn't seized and I was able to rotate it by hand and get hot air into the car. If you've not seen it before, it's not that easy at first but Dave's description should help you to find it.

Good luck - hope your's is like mine was !

Cheers

Julian