Ask the Editors: Disappearing Antifreeze

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Dear ATVC: I have a 2004 Kawasaki KFX400 that is losing antifreeze after a short ride. While idling it doesn’t smoke, but when you rev it while idling it will blow out white smoke from the exhaust, not a lot but the first rev can be quite a bit. It doesn’t completely lose antifreeze but it lowers in the radiator. Any suggestions? xreynolds95

When diagnosing missing coolant, the general places to start are to look just below the water pump for signs of moisture/ antifreeze dripping on the frame. This usually indicates a bad impeller seal. Next we usually take a close look for moisture around the thermostat housing and all 4 of the hose clamp junctures.

However, since you do report the presence of white smoke when you rev the machine, it’s much more likely that antifreeze is making its way into your engine’s top end. This is usually the result of either a blown head gasket or a cracked head.

In a later post, you claim that the oil looks fine (usually it appears thin and milky when exposed to coolant); which tells us the leak is likely still a small one. Most likely a head gasket on the verge of failing (sealing partially). Doing a compression check is the way to determine the extent of the trouble.

Fortunately the Kawasaki KFX400 is the same ATV as the Suzuki Z400 (as well as Arctic Cat DVX400) so OEM and aftermarket parts are incredibly abundant. A new top end gasket kit goes for around $30. If the replacement is beyond your ability mechanically, it’s a fairly common dealer procedure.

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