Howling noise

[John Hennessey]

When I turn the key to start the engine before ignition we get a howling sound when the coach has been sitting for a while which goes away as soon as we start the engine. We’ve noticed this for a few years and was wondering what it could be.

[David T. Richelderfer]

My first thought is the low air pressure alarm.  But it should keep "howling" until the air pump gets the air pressure up.

[David Ciotti]

Are your fans for the dash heat and AC off?  Mine make noises when the voltage is low.

[Jerry Carr]

David our 06PT also made the fan noise also we could hear the electric fuel pump until  the engine pressure is present.   

[John Hennessey]

What did you do to stop it?

[Jerry Carr]

John the Heat/cooling fan just needs to be turnrd off, Its easy to just shut down with key when you stop but when you turn the key back on with the fan running you can hear it. the fuel pump will stop whenyou have pressure or if the engine pump has taken over.
The noise you have may not be these but the cooling fan was somehing we could hear. I would  just turn it off no problem.
   

[David Ciotti]

My fans only make noise when on the lower settings.    I turn the fan speed switch to a higher level to eliminate the noise.  When the engine starts the alternator will boost the 12 volts to speed up the fans.  Eventually I will have to replace the fan motor.

[Fred Brooks]

  The blower motors have bronze bushings and after 20 years the lubricant dries up. Replacement blowers are available at Napa parts houses. If you have a split system like a Marquis, there are 2 blowers and one turns clockwise and the other blower turns counterclockwise. As I recall, I believe they are around $40.00 each. Fred