No do not do that. A pressure washer does not belong any where near a motor. You can and will cut houses and wires. You can rip old wires out of connectors ect…. Motors need to be steam cleaned. It’s a 28year old truck. Everything is brittle. Not that I would pressure wash a brand new truck but being old makes it worse. A PS also has many sensors that should not get soaked and you can end up with water down an intake.