Coolant seals are o-rings, but they aren't the only o-rings in the engine.

Dave

Thanks, Dave. That's what I needed to know. :)

not on the pics he gave on the pics from Banzai!

Well, The odd thing about this is that its the front plate coolant seal and its opposite from the exhaust port. Which is pretty rare seal to blow out.

Most of the time, its the rear housing close the the exhaust port because its the point where its the hottest. My engine also lost a coolant seal and two other engines with blown coolant seals that I bought weren't at this spot. And to me, its hard to tell if its acturally the coolant seal or not... I need a closer pic of it.

Another point I would like to make is make sure you get your plates lapped and make sure get your engine built by someone with a lot of experience and either willing to ship out the plates or have a lapper... Which most rotary shops do not have one. Also, I think OEM coolant seals are the best to use. Don't believe the hype of these other coated seals. But that's my opinion and I'm sure someone else on this forum will say otherwise... Just make sure to acturally see them side to side and inspect them well and see the difference between them.. Just remember that many many OEM seals have lasted 10+ years.... before the PFC to turn on the fans earlier.

BTW, that inner seal looks like the teflon ecapsulated ones like Rotary Aviation sells. Your picture is blurry though.

IMO and what works best for me in regards to purging air from the engine is to fill the coolant with the small coolant line off of the back iron housing. It's the one coming out of the top of the rear housing that feeds the throttle body. The air that is trapped seams to get stuck back there.

yeah post a bigger cleaner picture of that...

:lol: I resurrected charlies post from like 7 months ago to ask my question about coolant seals. I wonder if he's noticed?

I think you can get more pics from the Banzai Racing site.

Charlies engine had internal coolant loss at the front combustion chamber, it also failed the hydrocarbon coolant test. Coolant was evident in the front chamber, very simply test, pull the plugs and rotate the engine backward, coolant pours out.
90% of the coolant seal failures we see are on the front housing, the few that we see on the rear housing are due to the retaining wall eroding to point that there is no longer enough material to hold the seal in place.