loosing coolant from expansion tank on mondeo 07 plate

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loosing coolant from expansion tank on mondeo 07 plate

Unread post by guest » Sun Feb 26, 2023 8:31 am

loosing coolant from expansion bottle changed water pump and cap also thermostat and expansion bottle

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Re: loosing coolant from expansion tank on mondeo 07 plate

Unread post by carriedi » Sun Feb 26, 2023 4:55 pm

how are you determining that you are loosing coolant? Are you filling the overflow tank to the lower level after the engine has been sitting over night? (lower level in the overflow tank should be the cold level) That is the only level to use to check for coolant loss. If the lower level keeps getting lower or empty altogether the I would low for a leak somewhere in the cooling system. check all the hose connections. Make sure you don't have a loose hose clamp somewhere. Then look for leaks at metal connections like intake manifold, freeze plugs etc.

Has the engine ever overheated? Or got into the red on the temp. gauge? Head gasket could be a possibility too.

the way the overflow tank works is the expansion of hot coolant passes the check valve in the radiator cap as it expands. when it contracts it is pulled back into the radiator. If there is any leak in the cooling system, it could leak coolant under pressure and pull more coolant from the overflow tank on the contract. (if it is a small leak) If you have a larger cooling system leak then your engine could push coolant into the overflow bottle under pressure but pull in air through the leak under contraction and the overflow bottle may not get low but the radiator could be low on coolant.

it's something that you have to watch over time. when the engine is cold or you can visually see a leak

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