Why do so many log skidders burn?

We see lots of burned log skidders.

The fire nearly always originates in the engine compartment, and the damages is so severe it is impossible to determine the cause.

We had the opportunity to survey a skidder for a claim which necessitated viewing the bottom of the oil pan. Scroll to the bottom of this page to see what we found...

We removed the skid plate under the engine compartment....

What's this? Loaded with oil soaked wood chips and saw dust...

Clean much?