Cooling issues???

[zach R 7x]

I have a 2007 450 with a fairly fresh motor and I am having problems with loosing coolant out of the radiator cap. I can fill the overflow bottle and it will suck it out with in 15mins of riding and the frame is all wet next to the oil tank and nerfs. Fan is running all the time, so I know that is not the problem.

Seems to me it is comming out of the cap for whatever reason. Can it be just the cap is bad or is it building pressure and pushing it all out? Motor doesn't seem to be getting hot duriing this , as I have shot the cyl with a pyrometer and it seems to run around 190-210 at the worst.

I really don't want to smoke this engine!! This is a mx quad and is run hard for 20-25 mins at a time.

[250r4life]

you may have a hole in your radiator or your cap may be bad.

i would think losing coolant that quickly it would be fairly easy to see where it is coming from.

considering it is winter, i also think that is odd that your fan is coming on at all, let alone running all the time.

[bearball12]

I would pull the radiator and clean it really good with a water pik. Soak it again a clean it again. Amazing how much build up can happen when the radiator looks clean. May also want to try Engine Ice as a coolant.

[zach R 7x]

sorry guys, been real busy and forgot to post what was wrong. Well... it was a crack in the top tube in the radiator, right next to the cap.

I stripped the plastics and ran it w/o the fan on to bring to temp and it started to spray. Got a new one and back on the track!

We actually run our fan pretty much all the time, it is on a switch not a sensor. Is this bad?

[guy310]

Its not bad for it at all I think he just meant it was odd that it comes on often. Most YFZ's I have had have not run the fan too much. Mine comes on in the summer when its very hot out and only if I'm really riding it hard.

[zach R 7x]

I get the motor warmed up and then turn the fan on. I get nervous that it may overheat without it on.

Should I be able to run without it on, especially in the winter? Does it starve any power from the motor when runnnig?

[guy310]

You should be fine, YFZ's are not known as hotter running engines and like I said I have never had any issues with stock or heavily modified engines. I have been on YFZ's since 04.