I've located the OPS, but I'm not sure that replacing it is a job that my big, clumsy fingers can do. Is it an easy job, or are there parts that can break easily?

If it's been on there for a while it may be difficult to get off. I had to remove the oil pressure sender tube completely out of the car with the unit attached and then put a vice grip on it to get it off. If it's not that fused on there, then it's simply putting a wrench on the square top of the tube to hold it in place and another wrench on the actual base of the oil pressure sender to get it off. Don't try and remove it by any other way, such as trying to screw the actual sender itself off which a few have done and damaged the sender. It should always be removed and installed via it's base.

edit: is this a 2.8L?

[This message has been edited by Fiero84Freak (edited 02-25-2013).]

Yes, it's an 86 2.8.

Yeah it'll just depend then on how long it's been on there to the difficulty of removing it. Regardless you'll likely have to utilize vice grips at some point.

Here's what I unfortunately had to do. Because of the position of the battery tray, I could not get a large enough vice grip on the sender to remove it, so I removed the entire sending unit with the tube assembly.

Removing the hold down bolt for the tube.



At the very bottom of the block near the oil filter screw on point is where the tube goes to. I put a flare wrench on that.

Both off as a single unit.



From there I could get both a vice grip and a flared wrench to remove the sender (this was actually me putting the new one on).



I had to do it this way because I simply could not get both wrenches into a position with the battery tray in place to turn the sender. I kept busting up my hands. Again, yours may not take such difficulty getting off, but it depends on condition of the unit, miles on the car (mine had 279,000 miles at this point), and luck.

I did not put thread tape or sealant on mine and I have no leaks out of it. I've read that it is supposed to "ground" out through the threads, so if you put a thread tape on the threads you may mess with it's ability to actually work properly.

[This message has been edited by Fiero84Freak (edited 02-25-2013).]

Replacement can be done pretty easily without removing the sending tube. First, you'll need to remove the battery to get those 'big fat hands' in there. Next, get yourself a small crescent wrench. 8 inch works well. You'll also need an open end wrench. I think it's a 14mm or 9/16.

Look at the picture below. You can see the sending tube coming up to the sender. It transitions into a square block. This is where you use the adjustable wrench to hold it stationary so you don't twist and break the tube. Next, look just above the square block and you'll what appears to be a hex nut. That's where you use the open end wrench to remove the sender. It's not a nut, but part of the sending unit. Don't be tempted to grab some Channel Locks and twist on the sending unit. That big hex shaped area on the sender body isn't designed for that. Why they made it hex shaped, I don't know.

Now, when you go to the auto parts store to get your sender, pick up a cheap mechanical pressure gauge. SunPro makes one that retails for about $15. Screw it into the pressure sending tube, let the car come to operating temperature and see what your real oil pressure is at idle speed. By doing this, you have something to compare to when you install the new sending unit. BWD and Sorensen have a long history of being inaccurate.

Fiero84Freak's advice regarding tape or sealant is correct. The new sender comes with a sealant coating already on the threads.

[This message has been edited by fierofool (edited 02-26-2013).]

None of the above will make sense if your car doesn't have air conditioning since the oil pressure sender will be screwed into the oil filter boss like so:

The oil pressure gauge on my 1988 Fiero Formula has started misbehaving. Most of the time it reads normally, but every so often while the engine is running it "pegs" up to well over the max (all the way round clockwise to the right until the needle is horizontal).

Familiar problem, it seems: the sender unit is acting up because moisture has got into the connector or the top of the unit.

I have found various posts which mention - and some attach - the tech service bulletin which recommends a modification to remove the mounting tube cpmpletely and - even on the vehicles with A/C like mine - fitting the sender unit directly down into the hole beside the oil filter. Means re-routing the wiring and connector as well. The posts above are helpful because they have pictures which help to explain the task (although the actual sender on my '88 looks different to the one in the photos).

Not the easiest of jobs, because of the access problem (I'm really not prepared to take the engine out just to do this!). And to avoid fouling the a/c compressor, or the drive belt, or other stuff down there, the TSB says you have to get (a) a 1/8" nipple to fit the hole; (b) a 1/4" to 1/8" reducer; and (c) a 1/4" 45-degree angle connector (into which, presumably, you fit the new oil sender unit).

Apart from the difficulties of getting at this location to remove the tube and then install the sender, the TSB assumption that the various connectors/reducers/angle-bits required are available at any hardware or plumbing supply store is misplaced - at least in those parts of the world where plumbing equipment has gone metric....

I'm wondering about other solutions. The most obvious one seems to be to keep the tube in place, and to fit the sender into the top of the tube - as it is now - BUT instead of having it sit vertically (with the connector going in the top, and water able to drip down directly into it), putting a 45-degree or, better, a 90-degree elbow fitting into the top of the tube so that the sender then fits into it at an angle or horizontally.

I haven't yet got a new sender, and haven't even looked at whether a 45 or 90 angled elbow fitting is available with the right thread-size. But is there any flaw in my thinking that I have not spotted?

[This message has been edited by br1anstorm (edited 06-23-2014).]

br1anstorm, the 90 degree fitting at the top of the tube should work very well. I've also used a large diameter section of the split plastic wire loom cover to slide down over the sending unit, keeping the split turned to the back or engine side.


A couple of weeks ago, I saw an 88 that had a small 4 oz plastic bottle with the bottom cut out, using it as a shield. They had cut out the bottom, split it up the side to get it over the harness and sender, then wrapped it in tape. Didn't look so good, but it worked.

[This message has been edited by fierofool (edited 06-23-2014).]

Here is what I found covering my OPS unit just a few days ago.

https://www.fiero.nl/forum/Forum2/HTML/000310.html

While you're doing this it would probably be good to switch to '88 sender. There are threads on this. You need a new connector and some wiring changes, but the '88 sender is cheaper, better, and more reliable. I bought two, but haven't done either car yet.

TFS sells a stainless tube to replace the mild steel original that sometimes rusts through.

I had the dealer replace the sender in February when it was spewing a quart a day. They couldn't get the car started until the next day. Me thinks they didn't know about not using tape on the threads.

If you use that insulation stuff it would probably be better to wrap it with aluminum tape. It's never caught fire in any of the vehicles I've used it in, but I don't think it's meant for automotive use, especially under the hood.

I used to insulate engine bay AC pipes on the theory it would provide more cooling cheaper. Maybe it does, but it seems to make the engine compartment hotter, which may very well make you hotter as well, so I gave up on that.

quote Originally posted by 85 SE VIN 9: While you're doing this it would probably be good to switch to '88 sender. There are threads on this. You need a new connector and some wiring changes, but the '88 sender is cheaper, better, and more reliable. I bought two, but haven't done either car yet. .

Even with the 88 sender, water can get into the top and cause it to malfunction. Shield it as shown or in some manner.

http://www.gafiero.org/bbs/index.php?topic=1642.0