I'm replacing an oil pressure sending unit and I want to confirm it's the correct one before I shove it into place.

The old one has a push on electrical connector and has the following info on it:
[VDO Logo]
10 87
29/74
0-5 bar

The new one is a bolt on electrical connector has this info:
29/59
3.04
0-5 bar

The pressure ranges are obviously correct, what I'm wondering about is the 29/74 and 29/59. I'm wondering if those are OHM readings. If they are the new one will obviously read wrong.

this might help ...

Andy

This is partially conjecture, but from what I've been able to tell, the ohm ranges are basically the same on nearly all VDO senders for OEM use: 10-180ohms. What changes is what 10 and 180 ohms mean. This means that if you hook, say, a 0-5 bar sender to a 0-10 bar gauge, the needle moves in exactly the same way as it would with the "correct" gauge, only the markings on the gauge face are wrong. This is the problem my 914 has right now with the /4 in it. It has a 0-5 bar sender, but I have a 0-10 bar gauge, so it looks like I have 100psi of oil pressure revving after a cold start, but that's really just 50psi. Just divide what you see on the gauge by two, and you're OK.

The other numbers could be a production code (where and/or when it was made), or almost anything else.

The only exception I've seen to the 10-180ohm VDO range is the fuel level sender for VW/Porsche.