Losing coolant

[turbowrenchhead]

After the last trips 3 weeks ago I had lost a significant amount of coolant on the trail. I had to keep adding. I pressure tested the system and it holds pressure and there are no external leaks that I can see. I pulled the head and on of the o rings didn't look perfect so I replaced it. I rode again last Saturday and I'm losing 8 oz of coolant per fuel tank of gas. The radiator hoses are new. The one from the water pump to the head is original. I ordered a new one just to eliminate the possibility of it being the cause.

[BUILDER]

Sounds like it is getting hot and blowing it out or your cap is bad and you are loosing coolant from the cap. 

[turbowrenchhead]

Good idea, I should get another cap. Any recommendations? I have one of those Chinese ebay over sized radiators. Does an OEM cap fit?

[turbowrenchhead]

How can the cap let almost all the coolant escape? Three weeks ago on my first trip with it I lost 25~30 oz of coolant.

[D.N.K]

yes it is the same, and better quality

[Dick Dragon]

If the cap does not hold the pressure it will force the coolant out the overflow tube or around the caps seat.

[Starwriter]

Have you checked your trans oil lately? You need to pay more attention to actually where the coolant is going.

Is it going into the gearbox? Bad waterpump seal?

Is it overheating and expanding and going out the overflow hose? Like maybe bad impeller or waterpump gear?

Is a head O ring leaking and causing compression to push it out the overflow hose?

Is the radiator cracked and leaking?

A very slow leak will evaporate before it drips on the ground.

[turbowrenchhead]

New radiator, new billet pump and gear, just changed the o ring on the water pump metal hose at the dyno 4 weeks ago. Checked the case oil when I first realized the problem and its fine, no cream. Re checked again later still no cream. Just pulled the head 2 weeks ago and changed both dome o rings and copper washers on the head nuts.

I already ordered a new hose. I'll order a new cap too. I want this fixed before I go to WA the end of next month.

[Larry's Shee]

Has it always leaked or did the problem develope since you got it/ got it going? Just because rad is new doesn't mean it doesn't leak............... just saying.

[J-Madd]

Fire it up for a bit then pop the radiator cap. If it has pressure even though its not hot, the head is leaking. Also check the plugs. You can easily see water beaded on them.

[06350banshee]

Have you tryed relocating the overflow? i get the same problem with mine just seems to come out of the overflow usualy after going up a steep dune. All though once it gets to the low mark seems to stop leaking. So ive just left it

[06350banshee]

I found this also if it helps.

http://kuoi.org/~john/tips.html

[turbowrenchhead]

I'm not running a coolant overflow rez. I'm going to order a used stock unit and install it on the bike. I pulled my dipstick again last night and re checked it. I had some grey color on it. I dropped the plug and its discolored now from a small amount of water in the oil. I guess I'll replace the seals again.

[turbowrenchhead]

Fire it up for a bit then pop the radiator cap. If it has pressure even though its not hot, the head is leaking. Also check the plugs. You can easily see water beaded on them.

I did that and there is no pressure build up. The head gasket o rings were just replaced as well.

[turbowrenchhead]

Has it always leaked or did the problem develope since you got it/ got it going? Just because rad is new doesn't mean it doesn't leak............... just saying.

I never rode it before the restoration. This is a problem that was present right away after I started riding it on trail 3 weeks ago.