Fluctuating / Erratic Oil Pressure Gauge Fix
Like a few other F150 owners I’ve spoken with, my 1997 F150 was plagued by an erratic oil pressure gauge. Specifically, when cold, the gauge would work normally. However, after the truck was completely warmed up (I commute about 25 miles each way to work), the gauge would begin dropping down, sometimes to the point of setting off the oil pressure light. Sometimes I could get the needle to begin reading normally again by fluctuating the engine RPM, but this “fix” was hit or miss. Although I was quite confident that the gauge was indeed malfunctioning, I could not completely ignore the fear that I really was dealing with an actual pressure drop.
A few days ago, I traced the wire leading from the oil pressure sensor (located very near the oil filter) to (behind) the dash. What I found was that the wire, encased in a high temperature insulator, was routed VERY close to the exhaust manifold (within an eighth of an inch). I theorized that, although not burnt, the wire’s electrical properties were being changed by the ambient high exhaust heat. I rerouted the wire completely away from the exhaust system (after encasing it in new loom/split casing), crossed my fingers, and went driving.
A final thought – I do still believe it to be a VERY good idea to install a “real” oil pressure gauge as many on this board have recommended; I plan on installing a mechanical one in the next week or so. Anyhow, sorry for the long-winded post, but perhaps it’ll help someone, as reading many of you all’s questions/responses on this board has helped me.
Take care all,