The part number is 996106 447 04 (the original was the same except the last two digits were 00). Available from Pelican, Suncoast, etc., etc.

Brad

That seems to be my luck with the caps, have always had that condensation so I've ordered yet another "04" cap.

2000 Boxster S 82,000 miles with original cap and no problems.

Many responses here are "milage" and "no problems".

Isn't a coolant cap replacement, before a problem appers, the whole point? As a preventive action?

I ordered this one:
PORSCHE 911 BOXSTER CAYMAN COOLANT EXPANSION TANK CAP | eBay

I also got my -04 cap like this from a respected indy. The tag on the bag looks genuine, so hopefully it's ok. The missing part number could be an annoyance down the road...

http://986forum.com/forums/uploads01...1377108125.jpg

Cap, coolant tank, and sensor replaced at 128000 km. No condensation or leaking issues at that time.

Well my problem was that each time the cap needed to be taken off to flush the coolant, replace either the coolant tank or water pump, all things you must be doing if you want your head to keep from cracking, the result was that the old cap could not keep a tight seal and air was coming in. This is potentially big big problem if left ignored.
Each time I immediately brought my car back to shop to get the air out but for whatever reason we didn't consider the cap to be the culprit and figured it was that the system hadn't been burped correctly. A bad guess since we were using vacuum fill so air couldn't have gotten in....unless the cap was bad.

So people who are on the original cap with no issues are probably also people who have never replaced their water pump (a potential problem) or people who have never flushed their coolant (a problem if factory coolant has been mixed with generic coolant) or someone who still has the original coolant tank (which often crack because the old cap lets air in after a flush). In other words if your going to take care of your engine properly this must include replacing the coolant cap every time you flush the coolant or replace the water pump. If you do none of these things maybe you'll be lucky. You should also replace your hoses when you do the water pump for the first time.

Interesting. My -04 cap looks nothing like that...

http://986forum.com/forums/uploads01...1377123690.jpg
http://986forum.com/forums/uploads01...1377123702.jpg

Could be a VW cap ? I'd replace it asap.

Not VW. See my post above, where I show the bag with the correct Porsche part number. And I bought it from a well-respected indy. And apparently I'm not the only one with one like this...

I agree with ekam. Maybe you picked up the wrong one. Got mine from the dealer recently and it's identical to the top one pictured.

http://986forum.com/forums/uploads01...1377126411.jpg


This is what my packaging looks like. Similar but not exact.

Either way, get the OEM one direct from the dealer - order from Suncoast or Sunset, both ships to Canada.

After reading this thread I think I'm going to pickup the 04 cap tomorrow just to be safe... I noticed there's condensation around the cap area recently. (I have 03 cap and it's around 2-3 years old.)

Changed mine in May. My coolant level was getting low (around the 'min' mark). Wasn't any sign of residue around the cap area and it was dry under the carpet. Since the cap change and top-off the level has stayed just below the full mark.

78k with 02 base original cap...looks like I will be switching caps soon.

I have the same. No part number on the cap. Weird. My indy strongly favors using OEM whenever possible. Maybe this is new VW takeover stuff...
suppliers are not being directed to follow part numbering protocol strictly. But that meshy thing on one and not the other seems weirder.

OK - so another dumb question. If you replace just the cap. Say I order one, it shows up, I take the old cap off, put the new one on (i just checked and mine ends in 01 so it must be an original), am I going to have a problem with air getting into the system by just changing the cap???

I'd just make sure that the engine is cold, say after it's sat over night you'll be fine. Unless you've been having to add coolant recently which might have introduced air into the system.

Since this car is new to you I have a general rule when it comes to anything coolant system related:

Don't guess. Have the professional check everything out. You can't kid around with this part of the car.

The cap is cheap but plays a critical role. In my opinion, the latest cap should be part of the PPI, as well as replacing the coolant tank. Coolant should be flushed at some interval, people debate how often, but once you decide to do this you have to make sure it's been done right by previous owners.

I will post pics later but I found white residue outside of my 03 cap. Will post pics later.