Quote:
Originally Posted by parnelli
Thanks Larry. We'll see what DryCreek thinks.
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Howdy,
I responded to your PM. Yup, Oil Pressure Sending Unit has failed.
Without the engine running, you don't have anything providing pressure.
* The oil pump is and internally-driven gear type pump. It relies on the engine and is geared from either the camshaft (sometimes via the injection pump) or from a belt driven pump (Cummins Big Cam 8.3L <- old design).
* - ETA, some folks have installed prelube pumps (aftermarket) on their engines. It is usually only done by serious gearheads and probably not a modification you'll find on many motor homes due to the low mileage they typically see. IF you had a prelube pump you would hear it start and run, and you'd have pressure with the key on. Once you started the engine pressure would be higher than normal, but then go to a normal range once the prelube pump kicks off due to either a timed relay or a pressure switch. I seriously doubt you have a prelube pump installed. I just didn't want to be caught making an absolute statement (should have no pressure with engine off) when there is the off chance you have a modification made to one in a thousand engines.