I've done some testing and found that I have one, or several, bad coolant seals. I'm planning to rebuild it myself and pay a shop to do a street port. I have a 1986 6 port, N/A 13B RX-7 with just over 90k miles. For the rebuild I'm getting Atkin's ARE316 kit. I'm wondering, should I get apex seals and replace them while I'm there? And, are there any other seals I should replace for longevity's sake?

 

I would recommend replacing the apex seals while you have the motor apart, the oem seal s are the best for reliability hands down

 

Even if they were to somehow meet spec it would be silly not to replace all hard seals and springs. That will include side seals too, which will have to be clearanced. Dont wait too long, coolant sitting in the seal grooves can cause pitting and ruin the iron (side plate). You can wait and see after tear down to inspect bearings and oil control rings.