New here! Will say right off the bat car knowledge isn't my strongest suit but i've been trying to tackle my latest problem. I've got a 2004 Ford Fusion.

About a week ago when parking up i noticed a puddle under my car (under the driver foot well it seemed to be coming from). Enough liquid to start trickling down the street. After looking under the hood i noticed my coolant tank was now near empty. So i re-filled it, with a coolant/distilled water mix and made my journey back. On the journey back i noticed a little bit of stream coming from under my bonnet and when i got home i realised my coolant tank was nearly empty again.

I re-filled it and sat on my drive revving my car, trying to heat it up and i noticed that my coolant tank was boiling, whistling, giving off steam and sure enough after a point water/coolant started spluttering out of the cap area. I thought it might be a dud cap so i bought a replacement one.

After replacing that i decided to re-fill it and make the short half mile trip to the petrol station to test it, i noticed some steam again, and this time i felt like i could HEAR bubbling coming from the tank. I also felt like the power steering got heavy turning corners, not sure how/if thats related but has never happened before. Sure enough when i got back the coolant tank was completely EMPTY again.

I've checked my oil, there is no milky white coloration in the oil etc. There is no oil in the coolant tank either. I am wondering if replacing the actual coolant tank is the next step. It holds liquid absolutely fine when the engine is off, level doesn't deplete so wondering if its an expansion issue.

Any suggestions/diagnosis would be greatly appreciated as like i said, relatively clueless when it comes to this stuff.

Thanks guys.

2 Answers 2


One thing that comes to mind is that you might have a badly slipping serpentine belt, except you haven't mentioned any of the squeaking noise that I would expect to accompany this issue. Is there any chance that whistling noise you heard was actually a slipping belt? The power steering assist reduction you noticed might point in this direction as well. A slipping belt would certainly reduce the ability of the water pump to circulate water between the engine and radiator and cause overheating.


As Gary mentioned it could be the serpentine belt. If that is fine, another possibility is your thermostat is stuck closed. This would cause the coolant to boil. Would also likely cause overheating. And if the coolant is boiling over it can get on your serpentine belt, causing it to slip and degrade your power steering performance.

Does the temp gauge get hotter than before? I dont know where the thermostat is located on those, but it is usually a cheap and easy diy.

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