Bad oil pressure sending unit

[WA 2 FST]

Scared the crap out of me yesterday. Driving home after working on one of my rent houses, and dispatching of some kid who wanted some in his hopped up Ford Ranger (yes, it wasn't fair at all, but he was baiting me and I was getting pissed at the constant revving of the motor thing)... I looked down after pulling away from a stoplight and see the oil press. warning light on, and the gauge is reading in the red.

I know these gauges/senders are cheap crap, and act like "on/off" switches. There is no fluctuation of the gauge. It either works or it doesn't.

I pull over, shut it down, pop the hood. Everything looks fine. Get back in, fire it up, gauge comes up to normal, then after about 30 seconds it goes down and the light comes on again. I wasn't that far from home, and knowing that if the oil pressure REALLY WAS near zero I'd be hearing all kinds of noise, I proceed home at a very leisurely pace. This was slightly against my better judgement, but it was in afternoon traffic, I had some place to be and I was thinking that if the motor was blown, Ford would be replacing it anyway.

Disconnected the battery, messed with the sensor some...didn't see anything abnormal about it. Still the same routine. Reads fine on start up, but after a bit it would fall off.

So I had the truck flatbedded to Bob Tomes Ford this AM (only b/c I didn't want any potential grief from the dealer...I fired it up and drove it onto the wrecker and we drove it off and into the service bay...:D . Turns out the sending unit had a small crack in it, a little bit of oil was getting on it, causing it to short out or something, and a new sending unit has fixed the issue.

[98Cobra]

http://www.redelephants.com/%7Eelephants/acatalog/10182_Built_Ford_Tough.jpg

http://www.talonclub.com/forum/images/smilies/rofl2.gif

Sorry to hear about your problems - but it least it was an easy fix. Mine has a "squeaking" when the motor is running. Used to only happen when the A/C was on, now its all the time.

[WA 2 FST]

Yeah, it was a simple fix. I was talking to one of the techs there that I know and he was saying that if it had really been zero oil pressure and I'd driven it two blocks, it would have been clattering like all get out. I told him that was the reason I kept driving and just listening, figuring it was nothing mechanical.

Or, like I told someone else up there... I could claim stupidity and if it had blown up, it was on Ford's bill anyway.

Fortunately the tow truck driver was really cool, loved the truck and was meticulous in putting it on an off and strapping it down. Turns out I should have just driven the stupid thing up there.

[Mark #2]

Just curious if the pressure sensor on the master cylinder is the same as the one used to detect the oil pressure?

[WA 2 FST]

That's a very good question! It looks similar, but I can't answer the question.

[L8 APEX]

No, diff switches.

[99WhiteBeast]

Just curious where is the sending unit located?

[WA 2 FST]

Per Terry, its located just in front of the motor mount on the driver's side. Very easy to access. Just looking at it, I couldn't tell anything was cracked or wrong with it, though. I tried unplugging the harness, jiggling wires, etc to no avail, just to ease my own mind that the sensor was bad.