Bad Radiator Cap?

[xclusivecar]

Just want an opinion...After every drive I have less coolant in my overflow tank. Lately the area under the rear trunk that seals the radiator fill area has had moisture. I'm assuming this means some water vapor is leaking from the pressure cap. I am going to buy the "new" cap since after reading many posts on this site it has been determined that the "new" cap is better. So, does anybody think this is where my "leak" might be? Also...what is the tiny pull-up lever located just to the front of the radiator cap? Is this the pressure relief valve? If so, after opening this valve I never hear any pressurized air escaping...thoughts?

[Tool Pants]

The lever is to bleed air. The air bleed has 1 or 2 O-rings and if they are bad you can get condensation on the trunk lid. But if you do not have the 01 cap that is where I would start.

[xclusivecar]

We shall find out tomorrow (Sat.) if the cap is the problem. I'm picking up a new cap and will give it a try. I'm hoping this is the source of my small coolant loss!

[xclusivecar]

UPDATE--

I replaced the coolant cap with the new ".01" style and after driving 70 miles yesterday the coolant in the tank stayed steadly between the low and high marks on the overflow tank. Also, there was NO moisture on the underside of my rear trunk lid! I now believe the old style coolant cap was allowing some water vapor to escape. Soooo, if you are loosing small amounts of coolant at a time and have the old cap, go spend the $20 bucks and try the new cap first. This very well may be your problem! :clapping:

Thanks to all for the opinions!

[Loren]

Anyone that has a cap with the part number ending in 00 should the cap regardless. It WILL leak.

[joee]

Is a new cap covered under the warranty ? Is there a TSB on this ? I just checked and both of our P-cars have the 00. Sure would be nice to ge Porsche to pay for one of them.

[xclusivecar]

Loren--

Your not kidding about the cap leaking! After putting another 70+ miles on the car there is NO condensation building up on the inside rear trunk over the cap! Just as important, the coolant level in the tank is now ALWAYS spot on!