As above. I read somewhere that the gaskets on vintage Omega crowns are somehow not replaceable and that the watches were designed to have the whole crown replaced at service. But I'm pretty sure that my vintage high-end Seikos have always come back from service (from a Seiko specialist) with a new gasket on the old crown.
The simple answer to your question is no. Some members have posted that they have successfully replaced the crown gasket on a Constellation but they are not designed to be replaced. (So wouldn’t be replaced in a standard service)
OK, good to know. I don't know the details of it but it seems odd that it would be extraordinarily difficult to replace any gasket, even if it wasn't designed to be replaced. Obviously I'm not going to be immersing any vintage watch in water, but I worry a little about accidental splashing and condensation in humid conditions for a watch that doesn't have any sort of gasket at the crown at all.
If you require more certainty then ask your watchmaker to replace the crown. Unfortunately some styles of Constellation crowns are no longer available new.
Japanese water resist crowns are totally different animal to the typical water resist crown. The Japanese crown has a small “0” ring which slips on over the neck of the stem. Easy on the Japanese crown, but not so on a regular water resist crown. Edited to change “neck of the stem” to “neck of the CROWN”!
Makes total sense - I had noticed the different design of the gasket on my vintage King Seiko crowns. The more I get into other brands the more I appreciate the practicality of my vintage Seikos.. But I also now feel very lucky to have managed to find a NOS gold-capped crown with intact gasket for my vintage Girard Perregaux.
Generally speaking, the only Omega crowns that are designed to have their seals replaced are screw down crowns.
Many vintage Seiko crowns are also not designed to have seals replaced, the seal is captive behind a washer that is crimped in place. However, as well documented on the internet, people have developed a clever way to pop off the washer and remove the seal, so a number of Seiko specialists are willing to replace the seal and washer for a cost.
Can you post photos of this crown? Might be good to show examples of the designs that allow easy replacement.
I'll post a picture when my watch is back from service. EDIT: actually you can see the gasket on this picture here:
Doesn't look right to me. The original gasket is square with flat surface. This one has a round O ring like the cheap ones sold on eBay.
Not a Constellation, but when I had my Seamaster 30 serviced last year, I specifically asked about replacing the crown gasket. The watchmaker said he could do it, but it would require sourcing a replacement crown, as the crown and gasket weren't separable. Since my gasket didn't show any excess wear, I opted to keep it.