2004 yz450f loss of coolant

5 replies to this topic
  • kylerf150

Posted September 27, 2010 - 10:57 AM


Hi guys i have a 04 yz450f with a big bore in it.
here's my problem i switched over to engine ice this past weekend and my weep hole started to leak again not as bad as the first time but just one or two drops while i sat there idling. after about 2 hours of riding my radiators took a little more than 3/4 a quart to fill them back up. I have read on alot of other forums that if you see bubbles in your antifreeze your head gasket is leaking when i open the cap i can see fluid being pumped right across the top of the radiator can someone explain a little more to me about what everyone means by bubbles,should i not be able to see the antifreeze moving at all when the engine is running or do i check for bubbles right after i shut it off??? also i saw about 250* degrees in some real tight trials this weekend is that too hot it ran about 200 to 210 on the rest of the trails but they weren't as slow going.I also filled my radiators up when i got to the truck and then i filled up my turkey baster and my turkey baster was empty about 10 mins up the trail.I am going to replace the water pump seals again and put on a boyesen super cooler and give it a try and see if im still losing fluid. i just dont understand the bubbles in the radiators i guess.:smirk: also i heard of a better coolant than engine ice what do you recommend?

  • grayracer513

Posted September 27, 2010 - 11:19 AM


Engine Ice is simply a high grade propylene glycol coolant with no silicates ready-mixed with distilled water. It's good, but it isn't voodoo or anything. It does have a little bit higher boil point than a typical ethylene glycol coolant (the standard green stuff), but only 5-10 degrees. If your cap is holding the 16 psi that it should, EI won't boil until around 270 ℉, and at that point, it's too hot. 250 ℉ is pushing it, but doesn't call for an immediate emergency shutdown.

Bubbles are not a reliable indicator of trouble because the coolant will normally foam quite a bit. One way to check for a leaking head gasket is to warm the engine up a little, then release the pressure in the radiator. DO THIS CAREFULLY! Use pliers, wear gloves, eye protection, and position yourself in such a way as to be protected from hot coolant coming from the radiator cap.

Once this is done, screw the cap back on and run it hard for a couple of hundred feet or more, but not for more than 30 seconds or so. Shut it down and see it it's built up a lot of pressure under the cap. If it has built pressure without raising the temp much, it probably has a leaking head gasket. A good shop should be able to test for the presence of combustion gas in the radiator for you.

On the water pump seals, be sure you check the condition of the shaft where the coolant seal runs. If there is a groove worn there that you can catch fingernail in, it probably needs to be replaced.

Also, read this post: http://www.thumperta...ad.php?t=785425

  • kylerf150

Posted September 27, 2010 - 11:41 AM


ok thanks i will go back to the green stuff in case i dont pay attention to what my temp gauge says at least it will boil over and ill know it sooner. I removed the cap several times during the ride and it was never under alot of pressure i did it all while i was still riding down the trail so maybe im just losing it at the water pump. I will inspect the bearings and shaft real good when i get it all tore apart.I will try and check for pressure like you said too.Thanks again also what temp is a immediate emergency shut down?

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  • grayracer513

Posted September 27, 2010 - 12:05 PM


I wouldn't necessarily move away from Engine Ice. The temperature is not so great a problem as boiling is, and a high boil point is a good thing, to a degree. The thing is that once boiling starts, cooling stops. Encouraging it to boil sooner is not really that good a plan.

Super high temp coolants like Evans and Zip-Ty raise the boil point to well over 350 ℉. This is getting dangerously high, but it is better than boiling over and loosing coolant in the middle of nowhere if you just can't keep the temperature lower than that.

If you have a leaking pump, it's not going to hold pressure anyway, so you need to fix that first.

  • kylerf150

Posted September 27, 2010 - 08:12 PM


i will fix the seals tomorrow and then check to see if i am building pressure after that.THANKS AGAIN !!!!!

  • kylerf150

Posted September 30, 2010 - 07:29 PM


well i replaced both seals and the impeller shaft which was wore pretty bad.There is a lot of rust in the y pipe and there was a fair amount on the shaft also.I checked the bearings, looked good to me i didn't feel any free play in them. its all good now thanks for the help grey.

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