What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Zero oil pressure

KRAUSEGB

Well Known Member
After changing all of the hoses per the 5-year recommendation, I started the engine to check for any leaks and the alarm went off, showing zero oil pressure. I did not have any issues with the sending unit up to that time.
I have read previous blogs, going back for some years and not sure what the consensus is for the best sending unit replacement. I have logged 260 hours and have the Dynon 180 efis.
I intend to move the sending unit to the firewall as has been recommended by many.

Gary
 
Did you purge the oil system after changing the hoses? Good chance there's nothing wrong with the sender if the system was not purged per the manual.
 
Part of a properly completed purge procedure is to turn the engine over by hand until an oil pressure reading is attained so you shouldn't be starting the engine after this type of maint. and being surprised by there being no oil pressure.

With the D-180, the oil pressure sensor is fed its reference voltage from the aircraft electrical system so if you somehow started the engine but then had the master switch turned off with the screen operating on its backup battery, the oil pressure would read zero
 
On the 912 series engine, I'd always pull the cap off the oil bottle and rotate the prop by hand until hearing the oil burping in the oil tank.
 
With the D-180, the oil pressure sensor is fed its reference voltage from the aircraft electrical system so if you somehow started the engine but then had the master switch turned off with the screen operating on its backup battery, the oil pressure would read zero

Or had the D-180 operating on the backup battery (cause I bumped the button while getting in) with the avionics switch off. Don't ask how I know!
 
Last edited:
Per the POH it has you start the aircraft on the backup battery. Note the oil pressure within 10 sec, then turn on the avionics master switch. There is no oil pressure with the back up battery on the D180, but as soon as you turn the avionics master switch on presto, oil pressure. Any thoughts? First time poster, long time listener.
Michael
 
Oil pressure

If you drained oil out of the lines you probably just need to spin the motor until the system is full of oil again. Loosen one spark plug on each cylinder and with fuel off and mag disconnected spin motor with starter until you see oil pressure. Could take 30 seconds.
 
I changed the oil and fuel lines and did the purge and found low oil pressure that would be high on taxi and lower in climb and cruise. (I say low, I mean somewhat lower than I was used to....was around 46 psi, and 'normal' was about 55 psi or so.)I was advised that some air in the oil lines might take a while to work out After about 20 hours of flight the oil pressure is back to normal and temps are fine. Sometimes it takes patience to let air escape.
 
If you drained oil out of the lines you probably just need to spin the motor until the system is full of oil again. Loosen one spark plug on each cylinder and with fuel off and mag disconnected spin motor with starter until you see oil pressure. Could take 30 seconds.

This is not the proper procedure for a ROTAX 912 ULS engine. If you have drained the oil lines then you need to perform a "purge" of the oil system in accordance with the procedures specified in the ROTAX maintenance manual. Just spinning the motor may not cause oil to flow and may result in engine damage.
 
oil pressure

Hi It is unlikely that the oil pressure sender failed whilst you were doing the oil line change unlikely but it is possible
You must follow the rotax instructions after full draining the oil system on a rotax if you dont you risk damaging a rocker or worse the bearings
You probably have one of three problems
1 No oil pressure because the system is full of air and needs to be purged
2 You have dislodged a wire from the oil pressure sender
3 Faulty oil pressure sender
 
Back
Top