My wife has a 2001 Exploder with the 4.0 engine. For the last two weeks the oil pressure fluctuates from very low to normal setting off the check gauge light. Doesn't happen every time she drives the car, just once in a while. I'm taking the car in today. Any guesses as to what it may be? I'm thinking either clogged sump or failing pump. Of course, it may also be a bad sender/gauge. I would think that a failing pump would be consistent rather than intermittent.
Off the "check engine light"??? Do you see an "oil" light? I had a car with a mechanical "fuel" pump that had some intermittent problems. A hole in the diaphragm was sensitive to temperature, it made trouble shooting very difficult. Go with the cheapest fix, starting with determining if the sending unit is functional. I bought a Ford 250 last year, shortly after purchasing it the oil gauge went low and stayed there. I put some cleaner in the oil prior to a change, and it went back up and stayed up.
My 2001 Ford Ranger had a problem with the oil pressure gauge when it got cold out. Dealer replaced the sending unit under warranty, no problem since. This is a known problem with Rangers, maybe also Explorers.
Ford oil pressure gauges are not a gauge at all, but are really an idiot light with a needle--I'll explain. The oil pressure sending unit is a simple off-on switch, NOT a pressure transducer that sends a signal to the dash gauge. The sending unit is open circuited with no oil pressure, and a short to ground with anything more than 4 PSI. The dash gauge is calibrated so that through the sending unit, when it is shorted to ground, the needle moves to roughly 70-75% of full scale--the gauge IS NOT really a gauge, but is an idiot light with a needle as I said before. Your problem is a common one---the sending unit is not making good contact internally, and when that happens, the dash gauge reads low. Replace the sending unit, and everything should be OK. Just make sure you get the right sending unit--the wrong one will make the gauge read normal with no oil pressure and zero with more than 4 PSI.
Good luck,
RON 2003 F-250 ======================================================== Remove the ZZZ from my E-mail address to send me E-mail.
*************** I have an '87Ford 350 with a 460 Motor. Does that also apply to my vehicle? If so I will get a real gauge ASAP. Thanks Geoff
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Remove the sending unit and hook up a regular pressure gage. See if the results are the same. If not, the sending unit or the dash unit could be the problem. Ron
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