1990 Volvo 740 Q&A

1990 Volvo 740 Question: 1990 Volvo 740 4 cyl. Hole burned through top of piston 4. What is the cause?

I pulled the head and there is a hole burned through the top edge of the piston. -
Answer 1
either something poked a hole or it ran so lean it burned a hole. lean could have been from a number of things -