Coolant Loss?

[owenlo]

Does anyone else experience small coolant loss over 5 or 6, 2 hour rides? I am finding myself refilling my reserve tank after about 8 to 12 hours of riding and was wondering if this is normal or if it should raise a red flag as far as a leak somewhere or overheating. Any advice?

Obie

 

[Mac]

My overflow tank is empty after every ride. It's useless, disconnect it from the rad and fill it with some premix to have in case of an emergency. The KDX rad doesn't like to be topped off, it blows off a few ounces then it's happy. Don't sweat it.

 

[owenlo]

Great Idea!!!

and Thanks, Thats why I love this site. Not only did I get an answer but a little Tip to boot.

Obie

 

[Robcolo]

COOLANT LOSS

Another thing to try would be eliminating every last bit of air from your system. Air expands greatly when heated and forces out some of your liquids. Remove the black plastic plug from the left radiator and fill it to the top, tilting the bike to get all air out of the crossover hose. This appears to help as long as you don't actually boil the coolant mix. I've completely removed the overflow tank as it effectively blocks air coming through the radiator.

 

[JustKDXinginNH]

My '95 KDX200 usually goes down to half a tank of coolant after being filled to the full line. Never loses any more, stays at half a tank always.

 

[gooby]

mine too if i fill to full line it drops to the middle of the full/low area it likes it there i guess ?

 

[KelvinKDX]

I rode most of last season w/o ever putting any coolant in the reserve tank. I check my radiators before every ride and they seem always to be at the same level - just a little breathing room.

 

[KDX'r in IN]

Same thing here

 

[NZMXr]

Good to hear this is something "normal" because I have been having the same problem , after just a couple of MX races the reservoir is down to about a quarter

 

[Gamb8]

I have a 91 kdx and the reservoir is in back. Call me paranoid but I didn't want to ride without a reservoir, so I just plugged the overflow tube. I figured it was just "sloshing" (technical term?) out. Anyway, I haven't had any loss since.

 

[Mac]

Originally posted by Gamb8
I have a 91 kdx and the reservoir is in back. Call me paranoid but I didn't want to ride without a reservoir, so I just plugged the overflow tube. I figured it was just "sloshing" (technical term?) out. Anyway, I haven't had any loss since.

Not a good Idea, plugging the overflow tube will prevent the overpressure cap from working since there is no place for the overpressure to go. When coolant is blown into the reservoir the air in the reservoir is pushed out the overflow making room for more coolant, by blocking the overflow tube you will cause the pressure in the reservoir to increase!

 

[Gamb8]

hmm... wouldn't the air compress a lot before it starts to significantly affect the pressure of the liquid? I mean how much does the volume of overflow change between hot and cold? I wonder if there is some other way to vent the reservoir, or even if coolant was leaking out the vent. I wish my bike was together to check, I've got it taken all apart for cleaning/lubing.

 

[Gamb8]

Note: I hope you just see that^ as discussion, I will take the plug out, better safe than sorry! I just want to have fluid so the radiator is sucking coolant instead of air as it cools down, thus not getting air in the system. I don't like filling it every other ride either.

 

[Mac]

The pressure might be so small that it doesn't matter im really not sure but they put the vent hose there for a reason and if the pressure climbs too high it might damage the rad. Instead of plugging the overflow maybe you could find a filter of some kind that will keep coolant in but let air pass through. :think:
Anyway I don't think its critical to keep the rad topped off, let it blow off a few ounces and then it will maintain that level all season.