Coolant Smell - Only On Start - No Leak

[herc_captain]

I'm wondering if anyone has experienced this before...

When I start my 2000 Boxster S I smell a bit of coolant in the air for a minute or so. Not sure that if it is coming from the exhaust or the engine compartment, but I have no visible leaks and the system loss is less than 1/2 cup over 2-3 months of daily driving. I've had this 'problem' since I bought the car used last summer.

Obviously I'm concerned about it being a major repair or damaging the engine, etc.

Ideas/advice?

[Loren]

Check your tank cap. If there is residue around the the cap/tank top then it maybe leaking. Make sure your cap part number ends in 01 - all the 00 caps are known to leak.

[herc_captain]

Thanks Loren,

The cap's part number does end with a 0, but it and the top of the resevoir are bone dry. Is it possible that the coolant system pressurizes on start and the cap very quickly starts working 100%?

I can try to get a replacement cap but I can't imagine not feeling some residue in that area if this was the case...

[Loren]

Well, that was the most likely possibility. If it is not the overflow then perhaps the new tank sensor fitting is leaking?

[herc_captain]

Loren - you were absolutely right. :clapping: New coolant cap = no smell on start + no fear of a greater problem.

I just couldn't believe that there wouldn't be some residue associated with the old cap leaking for 30 seconds while pressure and temperature rose on start!

Thanks so much for you help.

[stumpjumper]

I just started having the exact same problem, unfortunately I have the new cap though :(