Possible cause of split coolant tank?
11-08-2013, 01:26 AM
#18
Race Director
I have read that many times the coolant tank can split requiring a new tank and cap installment. Could this be caused by the pressure relief valve on the top of the tank, not lifting at high temps and the pressure consequently splitting the white plastic tank???. In other words the tank having a faulty relief valve? The reason I ask this question is after completing a spirited drive today (which brought the coolant temp to about 190F) I checked my coolant level without removing the blue top and noticed that the relief valve was then in the open position. Has anyone else noticed this happening to their car? I tried to close it but it went back up again to the open position.
The tank fails because of material fatigue and based on my second hand info along the bottom seam. This is a weak point.
There is no conspiracy.
The tank (indeed the entire cooling system) wants to maintain pressure for it is the pressure that keeps the coolant from boiling.
If the valve on top of the tank is open that's a problem.
BTW, 190F is not hot... The fans on my Boxster do not even turn on until the coolant temp reaches 212F and do not switch to high speed until the temp reaches 216F. I've seen the coolant temperature reach 226F and stay there, once in southern AZ in 116F ambient heat and another time more recently -- last summer -- when pushing the car hard in the twisties on a 90F day.