Question. While riding last weekend I noticed that the coolant started to boil after about an hours worth of aggressive riding. A couple of observations...I didn't notice the fan running consistently. Plus, on the right side of the ATV under the front (approximately under the right side of the instument cluster) there is a 1/4" black tube hanging down (not attached to anything). The question is this: What are some of the common reasons the coolant would boil? Would the electric fan (not running) cause the block to heat up enough for the temperature to rise to that point? Does anyone know what that tube is for? Is it supposed to hang freely like that, not attached to anything? (Possible drain tube?)

Thank you much for your input....

 

how long have you had the bike ? first thing I would do is pressure wash your radiator. mine built up with dust and mud and looked clean but wasnt.. a wash later ran like a champ. I would also grease the buss connectors in the front and rear, rear is a must.. front is just a precaution. when they get wet they corrode. there is a tech tip with pics in the nyrocs forum

 

Yes, an improperly working cooling fan <u>could</u> cause this problem, as well as a bad thermostat. (And bruteforcsbob's suggestion.) Low coolant or an air pocket in the cooling system could also be the problem.

If you have a blown headgasket, then the gasses from the combustion cylender could transfer into the cooling system, causing a bubbling effect in the overflow resevoir. Most <u>good</u> automotive repair shops should have a tester for this. (The tester is not very expensive.)

BTW, is that 1/4" black hose an old fuel tank vent hose?

Keep us informed!

 

the tube if its what I'm thinking is the overflow for your carbs. when you stand your brute up on the back rack gas should come out of it.

 

There is a PSB out for a connector that gets corroded on the rear of the brute that stops the fan from running