I have an '88 Formula. The good news is that I have the more recent, and apparently more reliable, oil pressure sender. The bad news is that it is still mounted vertically in its original location where water can drip on to it and get inside it. So it still gets temperamental and makes the gauge on the dash misbehave.

For some time I have tried to prevent the problem by wrapping the wiring connector and the top of the sender with waterproof tape. But finally I decided to seek a more permanent and reliable solution, and to replace the sender unit.

My Fiero has aircon. So the relocation of the sender unit as suggested in a factory service bulletin - fitted direct, using an adapter, into a mounting beside the oil filter and behind the aircon compressor - was awkward and difficult because of the access problems.

I looked at - and posted an initial message into - this thread on the Forum here, about the idea of putting an "elbow" into the original fitting at the top of the tube which comes up from the mounting beside the oil filter. There's a good technical drawing in this thread which shows the tube.

So.... for anyone else who might be interested, I thought I'd do a step-by-step description of what I did.

1) Disconnect and remove battery - not only for safety but also because it's necessary for access.

2) Remove the plastic shield which forms two sides of the battery compartment - take care not to lose the little cross-head screw which fixes the lower rear corner of the shield (nearest the bulkhead); it's difficult to reach.

3) Disconnect the wiring from the oil sender unit.

4) Unscrew the sender unit from the brass block to which it is fitted, using a appropriately-sized spanner (wrench) on the metal base of the unit. Careful - the unit is easy to break. The battery has to be out of the way to give room to use a wrench there.

Now for the modification:

5) Get a 1/4" NPT 45-degree Female-to-Male Elbow Adapter fitting. I got one of these

[Note: I had originally thought of putting a 90-degree adapter, which would then have the sender unit set horizontally. But that didn't work - not enough room, the elbow pointed the wrong way when screwed tightly in , and the wiring wouldn't reach. So I got a 45-degree one.]

6) the rest is simple. Screw the adapter elbow into the original threaded hole in the brass block, then screw the (new) oil pressure sender into the elbow. With luck it will be pointing at an angle which won't foul other nearby wiring or fittings, and the original wiring will reach. Then connect it up.

7) Replace battery shield and battery, and the job is done.

Here are pictures which show the adapter fitting in place, and the new sender unit installed.



The grey waterproofing tape is still wrapped round the connector. Don't be confused by that bare-wire woven cable immediately below the sender unit - it's an extra earth strap, as recommended in another forum thread.






I hope this might be helpful to others whose oil pressure sender has suffered from being soaked with dripping water.

The weatherpak connector should have a silicone bellows type seal around the part of the plug that inserts into the sender. The connectors are water tight when this seal is in place and not distorted during insertion. A dab of silicone grease (NAPA Silglyde) adds further protection.

Nice writeup, BTW.

Thanks, olejoedad. You're right - up to a point - about the "bellows" seal, and about adding a dab of silicone grease.

The problem however - at least with my oil pressure sender connection - is not the weatherproofing between the two halves of the weatherpak connection - ie the plug (on the end of the wiring) and the socket (in the top of the sender unit). The bellows seal makes it weathertight where those two parts of the connector clip together.

BUT...... with the oil sender unit in its original vertical position, the wires from the loom go into the top of that plug. Water dripping from above then seeps directly downwards into the connector from the top (or back) of the plug, where the wires go into it (and this eventually corrodes the terminals). The bellows seal doesn't protect against water getting in via that route. Silicone grease may help to do so, but isn't an absolute proof against water penetrating.

That's why I have kept the grey insulating tape wrapped around the wiring and over the plug where the wires enter it - even though with the sender at a 45 degree angle it is no longer so directly exposed to water ingress.

[This message has been edited by br1anstorm (edited 07-31-2015).]

There are also silicone seals (or should be) surrounding the wires where they go into the plug.....

Yup, that's true.

But water has a pesky way of creeping into things (capillary action). The car, and all its connectors, are now 27 years old - and like its owner (who is a lot older!) things begin to deteriorate with age.......!

That's a nice-looking fix. I wish we could get something like this for the oil filters.