At the beginning of the season before I pulled my machine over I thought I had coolant in one of my cylinders until I found out that the Arctic Cat oil I put in my cylinders in the spring had a slight green tinge to it. Before I figured this out I went asking questions to see what the problem could be if I had coolant in my cylinder. I was basically told to pretty much rule out a blown head seal because Yamaha uses o-rings. The only possibility would be a manufacturers defect and if that was the case the engine woud have blown by now. Everyone I asked told me that they are better and can withstand much more than the traditional head-gasket (This includes my anti-yamaha sources). Is this true? I am also told that the outboard industry is starting to use them. Recently in conversation a friend of mine said that they are not nearly as good as a gasket, but then again he is somewhat of an old-school mechanic and knows nothing about sleds, only four wheelers. Which is true, are o-rings better? I am confused.

I like o-ring over gaskets. O-ring came stock on some sleds back in the mid 70's so you can call o-ring old school.

My mach has o rings and the only way they will leak is if the head isnt torqued down properly or if there is a defect. *

They are also good for people that race that need to keep doing ring jobs and stuff.

My theory on why o-ring gaskets are better then conventional head gaskets are that there is far less gasket area,so in theory less area to leak from and blow out.I've found that in automotive application a rubber based o-ring type gasket will far outlast a cork or paper based gasket. http://www.snowmobileworld-s2.com/forums/iB_html/non-cgi/emoticons/wink.gif And like machzzz1 said if you are taking it apart often there is no old gasket to have to scrap http://www.snowmobileworld-s2.com/forums/iB_html/non-cgi/emoticons/biggrin.gif