Never. I don't see the need for it. 300 doesn't have one.

 

I've never heard mine come on even when commuting in high 90 temps. I'm thinking the two rads are efficient enough to cool the engine without the fan coming on.
And yes, we do get very hot and humid weather here in the summer at times. Not snow all the time LOL.

 

Is it made by redline? or royal purple? I used something like that for my car since I had the big turbo on it...guess it helped a little

 

Yeah, that's what I run.. I've never added to coolant though, I use a mix of distilled water & water wetter.. I think it's like 5 capfulls to a quart of water. Seems to work OK!

 

I've used Redline and Royal Purple's Purple Ice. Some years ago when I first heard about this stuff, I just believed it to be some kind of "snake oil". After reading more and actually finding out that some knowledgeable people that I know and respect in the motorsports field use it and know why it works...well...I tried it. I certainly won't try to explain the chemistry and physics of the stuff, but it basically allows a better heat exchange between the coolant and everything it comes into contact with. That causes the coolant to absorb the engine heat more efficiently and disipate the heat into the radiator more effectively.

I wouldn't waste money putting it in a vehicle that has a strong cooling system with little chance of overheating or even pushing the cooling system's envelope. My wife's HHR has a digital readout for the coolant temp, and I can tell it's often hitting up against the thermostat. My old 4X4 '89 full size Blazer has a radiator out of a diesel model, so I have trouble getting the thing warm even when rock crawling or pulling a travel trailer. I'm beginning to think my KLX doesn't need it either. My Vapor instrument temp readout has never exceeded 200 degrees in the worst conditions, and that's not anything while doing tight singletrack. My KLR650 did benefit from it, as those bikes run noticeably warmer. Still, the KLX has a relatively small cooling system, and bikes like these can get into some real jams while trail riding, so it's probably some good insurance to get a slight cooling system edge.

The bad thing is that it's about $15 or so per 16oz. bottle. The good thing is that the KLX only needs about 4oz.

 

mine came on once and scared the crap out of me, thought i screwed something up. i was "caught" a bunch of bushes, and was trying to power my way out of them...