Lost compression in cylinder one

Good morning.

Loss of compression can come from several places.

It could be a bad piston, burned valve, failed head gasket or broken valve spring.

You need to have someone do a leak down test on the cylinder. That is when they use shop air and inject it into the cylinder and they watch where the air leaks out. It could leak out the throttle body, which is an intake valve, exhaust pipe, which is a exhaust valve, the oil filler cap, which is a piston, or the radiator which indicates a head gasket.

Once that is determined then you can get a good idea of possible repairs.

Roy

https://www.2carpros.com/articles/the-reasons-for-low-compression