Coolant bottle pressure!!...WTF?!!!

[snailbait]

have a new 900 motor...with 3 rides on it....2 of the 3 rides, the coolant bottle has pressured up, and leaked out the overflow tube...then when I try to take the top off, it has massive pressure, and bleeds out about 1/2 to 3/4 of the fluid. I have bled it off twice, and made sure I had flow, then filled the bottle back up.
Anyone know why it keeps doing this...even after it's been bled off??...This is really starting to piss me off!!!

 

[900kingkitty]

same thign happened to me , was a blown inner head oring

 

[backcountryislife]

blown gasket, period.

pull the head & check o rings, use grease to hold the rings in place when you put the head back on.

 

[RACINSTATION]

Pressure in the coolant bottle is usually a blown head gasket or o ring. If it is an o ring, it will be the inner. Pressure from the cylinders is getting transferred to the coolant system.

 

[snailbait]

Thanks for all the "heads up" guys! I will pull the head tomorrow, and let you know what I find.
Steve

 

[snowmanx]

If it isn't that then it is your water pump seal. Fought with mine for a while before I found out what happened.

 

[snailbait]

UPDATE!!...

Finally got it tore down. All the gaskets and O rings appear to be in good condition...so took the mono head and domes and cylinders to the local machine shop to check specs. The cylinders were good...within a couple thousands...the domes weren't flat...about five thousands out...they fixed that....the head was out quite a bit too...not only on the sealing edge..but the ridges that hold the domes in place were good on one side..and about 5 to 8 thousands out on the other!! Got it ground down as much as possible...so going to put it back together tomorrow..and cross my fingers!
Thanks again for everyone's input!
I'll let you know what happens next week.
Steve

 

[high time]

Sounds a bit strange???????

O-rings were good? I'm not sure how it could have been the problem and still look good.

Owen

 

[backcountryislife]

Did you check the water pump seal like snowmanx mentioned? If coolant was getting past the o-ring you would be able to tell, you've got another issue & the head being out a tad isn't it.

 

[krom]

it will be good now, the part of the head that holds the inserts inplace was out, that keeps the head from clamping the insert tightly against the top of the cylinder, allowing pressure to push past the o-ring

 

[high time]

From my misfortune, I've never seen.......

an O-ring that will leak without it getting burned.

Owen

 

[Dentfixer]

had a simialar problem, it ended up being my therostat. It wasnt opening.

 

[snailbait]

Quick update....
Took her out on sunday...she ran strong! No coolant leaks. Between lapping the head and dome inserts, and new gaskets all the way around....She finally ran like a champ!
Super stoked!...and the Guys at RandR machine did a great job! They will get all my business for sure!
Thanks again for everyone's input.
It's greatly appreciated.

 

[snailbait]

had a simialar problem, it ended up being my therostat. It wasnt opening.

Thanks...I checked that...had good flow through the bottle.. After the other changes with the head, and gaskets...looks like the problem is solved!