On my truck if you look under neath towards the driveside, on the side of the engine is a fairly large round metal canister with a wire sticking out of the center. That is the oil pressure sending unit on mine.
Didn't know you still hadn't found it. Here's a diagram that shows it:
Hopefully when the crud is cleaned away it'll be more clear. Yours' probably doesn't have the Oil Level sender as shown, but the pressure switch should be in the location shown above. What about a wire going down to it, is there one just hanging? Perhaps a previous owner removed the sender because it was leaking and just plugged the hole...
known things: engine swapped a while ago, by P.O.. original oil pan because sender is there for oil level and it works. Location shown in the above post has a oil sender in it and that is the one that leaks coolant when removed. taking the wire for the oil press coolant sensor and grounding it affects the oil pressure light on dash. couple of hundred miles on it so far, still no mixing in either coolant or oil, not seriously consuming oil except for noted cover leaks..
millions of years ago, Ford used to put tapped plugs all over their blocks to machine oil galleries, but apparently they stopped that on this engine, since I can't find them, yet. If I can find one I put the OP sensor there and hard wire it to the cluster wire.
It should be on the driver's side, just in front of the engine mount. If there's coolant coming out of that hole when you take the sender out, then you've got something strange going on there...
Tiger Dan, you seem to be the man when it comes to this topic.
Is it easier to attack this thing from the bottom (I have a 9000lb hoist) or should I take the the air filter and all the junk around that and go at it from the top?
From the bottom seems near impossible. I put a set of channel lock pliers on but soon realized it'll just spin around and not actually un-thread. Seems like a 7/16's wrench that I'm going to need to bend to get in there.
You sure dredged up an ancient thread. I haven't had or worked on a 2.9 in so long now that I really could tell you the best way to get at it. (My '89 Ranger has a 5.0 in now in place of the 2.9.) If it looks like easier access from the top, then give that a shot. I seem to recall working on mine from the bottom and not finding it too hard to get at that way. Nowadays I'll try everything I can to work from the top of an engine rather than have to get down and crawl under. It's getting too hard to get back up again...
it depends... do you have an oil indicator light in dash or gauge?
The guage type oil sender looks like ann egg sized metal canister on a bolt threads, similar to shape of metal fuel filter canister.
The indicator light oil pressure sensor/switch/ aka sender is much thinner affair on bolt threads usually located at back end too of engine block, semidrivers side. With firewall its a bit of a pain to get at.
Still trying to find location of canister type, I believe its underneath, just passengers side of center line and a little above, possibly near oil filter.
I wish they were substantively called very different names and everyone stopped name swapping like there is only one kind in one spot that performs same function. For an 2.9 87 ford ranger, it depends on my instrument panel what I have and where its at.