DOES ANYONE KNOW WHAT COULD CAUSE MY 04 BAJA X WITH PRETTY LOW HOURS TO PUMP WATER INTO CATCH CAN AND NOT RETURN TO THE RADIATOR, IT TAKES A 1-2 HOURS AND IT WILL GO FROM MIN MARK IN OVERFLOW TO WAY ABOVE MAX MARK, WHEN COOLS NEVER GOES DOWN,AND RADIATOR HAS MUCH LESS WATER OF COURSE.IT HAS NO VISUAL SIGNS OF A HEAD GASKET AT ALL, NO SMOKE, RUNS PERFECT, DOESN;T GET HOT, NO ANTIFREEZE SMELLS,OR ANYTHING WEIRD,. I AM AFRAID IT MAY BE A HEAD GASKET ,BUT I COULDN;T SEE HOW WITH THIS KIND OF HOURS, AND RUNNING PERFECT. I REPLACED RADIATOR CAP WITH AN OEM ,BUT DIDN;T HELP, ANY SUGGESTIONS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

symptoms of head gasket would be coolant actually overflowing from the expansion tank - combustion pressure gets through the headgasket leak and overpressurizes the coolant system and forces coolant out the overflow. if you are not spewing over, then it is doubtful a headgasket issue.

I would first verify all air is out of coolant system by starting the bike and letting it run with the radiator cap off - as the bike warms up and the thermostat starts to open you will see the coolant begin to flow through the fill neck and bubbles will come up as air is purged once the flow starts. continue filling the radiator as the level slowly drops while these bubbles are being purged, and once it quits taking coolant and actually starts to overflow from thermal expansion and you are sure no air is left anywhere in the system then cap it. then bring expansion tank back down to proper level (the min mark) and ride.
see how she does now, and if you still have troubles then maybe I'd guess a defective radiator cap??

 

thanks for replay. i will definitely try that. also i forgot to mention there is no water in the oil. you said something about it spewing water it may be a head gasket. it seems if i rode it 4 hrs. instead of 1. that the catch can probably would start spewing over at the rate it is filling up now after only 1 hr. of riding. thanks for suggestions.

 

you almost never get water in your oil from a head gasket on these motors - there is only one small oil port coming up through the jug to the head for cam lubrication, and the likelyhood of the gasket failing at this spot is slim to none.

also, head gasket failure on a stock motor is rare, most head gaskets that blow are on improperly assembled motors that underwent mods, or highly modified motors with ultra high compression running exotic fuels.

but of course head gasket fialure is always possible, things do happen. if you do the filling procedure and adjust the proper level of the expansion tank, and end up losing coolant from overflow on long ride then a head gasket may be the culprit but I would first confirm that the cooling system is working right and not overheating causing the overflow - a dead fan, a dead fan thermo switch, or malfunctioning thermostat are the possibilities. And if you are certain the cooling system is working right, and then want to further entertain the notion of head gasket, a leakdown test would be a good idea, this is a test where the cylinder is filled with compressed air thru the spark plug hole parked at top dead center of the compression stroke and a special gauge measures the percent of leakdown over time to tell if it is holding pressure or not, and if the pressure is leaking thru the headgasket then it in turn will pressurize the cooling system.

watch for the red dash light while riding next - if you are losing coolant and the red light comes on, this indicates overheating, which as mentioned could be casued from dead fan, dead fan switch, or faulty thermostat. the water pump is too simple to fail, the only problems we really ever see on pumps is seal failure causing a leak.

 

O.K., I WENT RIDING TODAY FOR 2 1/2 HARD RIDING HOURS,I CHECKED WATER IN RADIATOR BEFORE LEAVING AND SIT AND LET IT RUN WITH CAP OFF, IT CONSTANTLY IS PUTTING OUT LITTLE BUBBLES UNTIL IF OVERFLOWS THE RADIATOR,IT ONLY TAKES ABOUT 5 MINUTES IDELING UNTIL IT STARTS PUTTING WATER IN CATCH CAN. I CAPPED IT AND CHECK CATCH CAN IT WAS WELL BELOW MIN MARK. OVER THE COURSE OF RIDING I PERIODICALLY CHECKED THE OVERFLOW AND IT SLOWLY WENT UP THROUGH THE DAY UNTIL IT WAS COMING OUT OF TOP OF CATCH CAN. IT IS LIKE IT GAINS ABOUT AN INCH EVERY 25 MINUTES. RED LIGHT NEVER CAME ON ALL DAY, FAN CAME ON ABOUT 4 TIMES, AND WORKS PROPERLY, I WAS RIDING WITH ANOTHER 04 BAJA AND OUR FANS WOULD COME ON AT ABOUT THE EXACT TIME. I AM GOING TO TAKE OUT THERMOSTAT AND CHECK IT. IF CHECKS OUT I WILL HAVE TO TAKE TO DEALERSHIP I GUESS.

 

I CHECKED THERMOSTAT IT IS OPENING AT ABOUT 200 DEGREES GIVE OR TAKE A LITTLE. THERE IS A RING ON THE OUTSIDE OF THERMOSTAT, NOT INSIDE WHERE SPRING IS,'"OUTSIDE", BUT ANYWAY IT IS BROKEN AWAY FROM THERMOSTAT, WOULD THIS CAUSE ANY PROBLEMS.ALSO WHEN I TOOK THERMOSTAT HOUSING OFF QUITE A BIT OF AIR BLEEDED OUT WHEN INITIALLY CRACKED OPEN, RADIATOR WAS VERY LOW BUT I AM NOT SURE IF THIS MATTERS. ** CHECKED PARTS DIAGRAM AND THE RING I THOUGHT WAS BROKE OFF THERMOSTAT ACTUALLY I THINK IS A WASHER THAT IS SUPOSSED TO BE THERE.

 

If there are parts that are broken off then you should deffinetly replace the thermostat.... after that however... you need to make sure the cooling system is bled completly. It sounds like there was a large air bubble in the thermostat.... how long did you let it run with the rad cap off? On a stock machine with a working fan you should be able to let it idle without overheating. Let the bike run cap off and don't worry about the coolant overflowing out the rad... just make sure it doesn't get too low. You need to give it time to push the bubbles out. At some point all the air will work its way out, and the level will drop again. When it does... fill up and then let it idle for a while again. Eventually you will see a very steady flow and all the air will have been purged from the system. Cap it fill your res to the low mark.

 

I LET IDLE FOR 25 MINUTES AT LEAST ,FAN KICKED ON, IT HAS CONTINOUS FLOW OF AIR BUBBLES OUT OF RADIATOR, AND NEVER SEEMS TO SUCK DOWN LIKE IT SHOULD.JUST KEEPS BUBBLING OUT.

 

after you shut it off and let it cool check the level in the radiater . that will tell you something.

 

Man, I think I would let it run longer... at least until all the air bubbles are gone... if its an hour its and hour... could be even longer if you have a stuborn air pocket. I say just let it bubble, and if it gets low top it off. Get yourself a 12 pack and post up in your front yard and watch the bubbles.[img]i/expressions/face-icon-small-happy.gif[/img]