weird sound at 1500 RPM
Ok so the deal is at around 1500 or so and about 5-10% throttle it sounds like my heater fan is on. Any more throttle it stops. The sound is coming from the engine compartment. The fan blower sound only happens when im driving. it wont do it when i rev the motor. Sometimes it makes the sound at idle when its cold. I hope im making sence with all of this. I dont think i have any power loss but this is my first diesel. Oh my truck is a 2001 f-250 4x4. Its got about 198k and an auto. Im only getting about 11 mpgs in town. I dont know if that relates but im trying to give all the info i can think of. Please help. Thanks guys.