VDO oil pressure sender failures

Electrical and Panel
21

Hello,

I had same issues with VDO sensors going out - it’s been a while for me - need to look at logbooks for the time intervals between the failures - it’s pretty unpleasant sight to see oil pressure going over the roof during the flight.. I began to research and someone mentioned somewhere that it’s better to get VDO sensor with a seperate ground connection (2 terminals up top one for signal and one for ground) supposibly self grounding was corroding and causing false readings… mine did have some whitish residue on “screw in” portion of it (but then seems like there was still plenty of bare metal remaining to maintain the good ground) none the less I went with the dual terminal one this time and it’s been a few years now not a single issue. Not sure it this was just a coincidence or that really was the issue. Failed unit below. Jab 3300 Gen 4

Minde

Failed VDO
Failed VDO1440×3088 274 KB

1 Like
22

Pay close attention to the two terminal VDO sender units. Most are still grounded through the 1/8” NPT.

One terminal is for the signal and the other terminal is for an idiot light - low oil pressure.

Bill N67WX

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23

If you are concerned about a screw in connection, making good electrical contact, try using something like copper anti seize on the threads :smiling_face_with_horns:

24

Correct. I got the one with the gauge and floating ground terminals up top. No warning light contact on this one. I am not sure if this is just a pure luck that it has been serving me for over 180 hours (perhaps slightly different internals that do not go “bad” as easy?) but the fact in my experience that 2 of the “originals” went bad within 80 hours of operation. Such is my case.

Minde

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25

Quite a few people recomend mounting oil sensors remotely (firewall?) to reduce the negative effects of vibration - I haven done this myself and have yet to have a failure. :smiling_face_with_horns:

26

I replaced mine unnecessarily. My front crank oil seal was leaking and throwing oil on the pressure sensor. I thought the sensor was leaking. However I did some research and they are prone to failing due to vibration and oil impulses being so close to the oil pump. I mounted the sensor on the firewall and fed it with a high quality hose. I had to solder a ground onto the side of the sensor as well, as the hose didn’t provide a ground.

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