ASK THE MXPERTS: WHAT ARE TEARS MADE OF?

Dear MXA,

I have a 2019 KTM 350SXF, and I am wondering what is causing a small amount of coolant to come out of the weep hole on the left-hand side of the head between the coolant hose and temperature sensor.

That is not coolant. That weep hole leads to the spark-plug cavity (see red arrow above). When water or condensation builds up in the spark plug cavity on top of the cylinder head, it is vented down to the weep hole next to the coolant hose fitting. Thus, what you see coming out of the weep hole is just water, not coolant. Often the weep hole can get dirt in it and not vent. To be safe, riders need to clean it out. The easiest way is to remove the spark plug rubber cover and blow air though the weep hole, either up or down.