Oil Pressure Sending Unit in "aft" block port. Why?

[Launchpad McQ]

Well the slow-and-steady "light" overhaul continues. The thread title pretty much says it all. I've read all about those failure-prone galvanized steel nipples used to connect the oil pressure sending unit to the block that catastrophically fail (which I have and intend to replace) but in pictures of others A4's I've usually seen them mounted in the forward port with an oil pressure safety switch located in the "aft" port. Any ideas why mine is in the back or just another example of previous-owner ambivalence?

[Dave Neptune]

It's all about your access and choice. Both ports are the same "oil galley".

Dave Neptune

[Launchpad McQ]

I thought I might be over-thinking this. Thanks Dave.

[JOHN COOKSON]

Another consideration would be which location gives the best run for the wiring.

TRUE GRIT

[Ajax]

Although either one will work, I believe the forward port was for the gauge sending unit, and the rear port is intended for a low oil pressure cutoff switch.

[BunnyPlanet169]

Although either one will work, I believe the forward port was for the gauge sending unit, and the rear port is intended for a low oil pressure cutoff switch.

+1 Especially as the OPSS wiring is usually coming off the coil+ from ignition, so it's right there. As said below, they're both oil gallery and will read the same pressure, and what ever is easier to wire. Personally, I don't like the forward oil pressure sender - in my compartment it's too exposed and a fracture waiting to happen.

IMHO - if you've taken the time to make it look nice, you're not overthinking!

[ndutton]

May I suggest getting the sender off the long pipe nipple and mount it on a nearby bulkhead?

[BunnyPlanet169]

May I suggest getting the sender off the long pipe nipple and mount it on a nearby bulkhead?

I'm not going that far to port, but I've seen some neat examples with short hose from grease guns.

This was my original installation, and it hangs out too far. I'm surprised I've never snapped it off. The rear oil plug was not functional on my original block....

[ndutton]

I had an array of senders on the forward pipe (gauge sender, alarm switch and OPSS), made the move before it broke and turned into a crisis. 300 PSI hose from NAPA connects it. Don't forget to run a ground wire with the hose.

[Ajax]

My engine is a little strange.

I have a mechanical oil pressure gauge, so I have a very small diameter copper line running directly from the forward port, to my gauge. No long extension.

[JOHN COOKSON]

My engine is a little strange.
I have a mechanical oil pressure gauge, so I have a very small diameter copper line running directly from the forward port, to my gauge. No long extension.

Why is that strange?
IMO mechanical oil pressure gauges are a good idea.

TRUE GRIT

[67c&ccorv]

Why is that strange?
IMO mechanical oil pressure gauges are a good idea.

TRUE GRIT

Until the pipe bursts/breaks.

[Ajax]

67-

I check it frequently. Since it tubing doesn't have a load "dangling" from it, it doesn't seem in any danger of breaking and it's corrosion free.

Mainly, my gauges are ancient and I wonder about their accuracy. That's the main reason that I might replace the gauges with new ones and new sending units. Of course, I could use an maintenance pressure gauge to test and verify what the old gauge is reading before I give up on it...