Oil pressure light comes on intermittently, often after getting up to normal operating temp. Goes off when engine revs. No knocking, runs fine, oil changed...still comes on. 160,000 miles.

The oil light comes on when the oil pressure sensor detects low oil pressure. The amount of oil has little to with it, although very low oil levels can cause loss of oil pressure. Since you aren't getting knocking, chances are the oil pressure sensor is defective. Replace it and monitor the situation closely. This could be a serious condition if allowed to escalated and it turns out to be an oil pressure issue.

You need to find out why you have low oil pressure. It is normal that as engine rpm's increase, the oil pressure will rise- the oil pump is moving oil faster. Even though your light goes out, you could still have critically low oil pressure. There should be sufficient pressure at idle to keep the light off. The light will come on when your oil pressure is almost nil- I believe for some it's as low as 8 psi. Normally, oil pressure at idle is specified anywhere from 15 to 40 psi. You would have to check specifications for your Expedition. To verify oil pressure, hook up a mechanical gauge at the oil pressure sending unit on the engine block. Check with a local shop.

The causes run from easy, simple to budget busting ruin. Low oil level, wrong grade oil, real old oil, oil leaks, internal oil leaks, worn oil pump, worn crankshaft bearings. It was pretty common on older very high mileage cars to have a fluttering oil light at stops and idle. It was time for a rebuild, or time to look for another car.

Check oil level on dipstick. Check for loose connection on oil pressure sender unit. Have the oil pressure checked using a master gauge.

Usually on idle (warm engine) this is OK.

blew something in lower end --oil pump damaged --no oil or low level --check oil pressure then do compression test as well --since knocking noise is usually called rod knock

you may have a bad oil sending unit the oil light works off of oil pressure i would start by changing the oil sending unit and if the light still comes on then you have bigger problems. get a mechanical oil pressure gauge and hook up and check the oil pressure after the engine has warmed up to operating temp you should have at around 30 psi but can survive with 10psi but might be time for a rebuild. if no oil pressure then you might have a broken shaft between the oil pump and the distrubuter. if the engine is running and not making any out of the normal ticking, knocking sounds probably just the sending unit though, they are about 25 dollars and i believe its right above the oil filter on the 6 cylinder.

Sounds like low oil pressure, is the engine making any knocking noises?

the oil pressure relief valve may be sticking causing a fluxuating oil pressure .this valve allows acess oil to flow back to sump hope this helps!

Hi:
Usually your oil light doesnt come on unless you have less than 10 lbs of oil pressure. You either have a bad oil pressure sending unit, or your engines oil pump is bad. The only way to verify your engines oil pressure is to buy a direct reading pressure guage and install it on your truck, or have a mechanic check your engine oil pressure. Eitherway, you need to do something soon, because the long term effects of running with low oil pressure will ruin your truck engine.

check oil type and u may have worm out rod bearing