Coolant Cap Poll

[JFP in PA]

Originally Posted by trimer

can someone help me here? How would a coolant cap keep you from losing coolant? I see on here that coolant was low, etc but no leaks...where is it going and how would a cap fix it? Is it just disintegrating into thin air because the cap is bad?

Sorry for the dumb question but I am really curious. I ahve a 10 yr old car with 18000 miles on it and the original cap. but want to know what a new cap would do...

The cap vents above a certain pressure (from the factory, about 18.2 PSIG) and can dump coolant out the overflow, but this pressure drops off with time and miles, which is why the cap needs to be tested regularly or replaced. Porsche has "improved" the original design at least 3 times to date, and as the caps are cheap, anyone that does not have a -03 or -04 cap is asking for trouble.

[Perfectlap]

Originally Posted by JFP in PA

Porsche has "improved" the original design at least 3 times to date, and as the caps are cheap, anyone that does not have a -03 or -04 cap is asking for trouble.

And that's if they are even checking the trunk to see if the coolant level is kosher...

I got in the habit of of seeing what's doing back there after my last coolant flush. I missed many opportunities to make the cap switch, like when the tank split and dumped all the coolant, as well as this last water pump. New cap should be part of any PPI inspection check list.

it's really amazing how such a minor thing can let a potentially big problem get away from you. The dash is not going to help you out until its way late.