The crash happened in Deer Park at Lake Cook Road and Quentin Road around 3:15 p.m.
Lake County investigators said it all started when a Honda Accord broke down, and the driver got out to look under his hood.
Investigators say the driver of another vehicle, a Honda HR-V, hit the Accord, killing the man who was underneath.
The Honda HR-V's driver and passenger, along with a passenger in the Honda Accord, were all hurt but are expected to be OK.
A school bus was also sideswiped. No one was in it, except the driver, who was not hurt.