I have had the subject engine's oil pressure light flickering on occassion
when coming down to idle in gear (about 700 RPM) after running for a while
on the highway. Figured possibly due to oil contamination from gas or
coolant, and solved once by changing oil to 5W-50 Castrol synthetic, but
came back again after about 5K miles. Recently changed oil to 5W-40 Syntec
(no 5W-50 available) and a new FL-400S Ford filter, and am still getting the
intermittent light (flutters) when coming to a stop after running at highway
speeds for more than a few miles, even with fresh oil. Does not occur
afterwards if not driving at highway speeds. Any blip of the throttle that
gets RPM up to about 900 clears the light.
The engine is getting up there in mileage (132K) and has always had oil
changed regularly. Oil always looks OK even when changed at 3-5K miles.
Other than the intemittent flickering idiot light at idle, as described
above, the engine runs great. PCV valve and oil passages are clean and
functional, no indication of blowby, normal oil consumption, no unusual
engine sounds, normal coolant temperature indications under all conditons.
At one point about a year ago, the engine went through a bout of slow
internal coolant leakage which has since been corrected with stop leak. Has
used very little coolant since then. Oil was changed after the coolant
leakage was found and fixed.
Any recommendations on a good set of aux gauges including oil pressure for
the Taurus? I believe my indicatons until they are proven wrong, so at this
point I want to verify that I dont have a bad oil pressure switch sending
Is what I am observing typical for this type of engine at 132K miles?
Interestingly enough, the owners manual for a new Volvo V70XC that I rented
on a business trip a few weeks ago stated that the condition I am describing
(flickering oil light at idle after a high speed run) is not considered
abnormal for that vehicle's engine!