2000 Nissan Xterra V6 3.3L.... I recently heard my engine begin to and almost immediately after my oil light flickered on and off and eventually came on. I thought I was low on oil, added oil and it seemed to repair the problem. About 30 miles later (the next day and after several short trips) my engine started to knock and the light came back on after flickering... I parked the vehicle and drove my wifes car to work. When I arrived back home, I started my Xterra and drove it for a bit. No knocking or oil light. About a year ago, I had my oil changed and about 3 weeks later I heard severe knocking and thought I was low on oil. I changed the oil and filter and it seemed to run fine (until now) ... Any suggestions?

Sounds like you may have accidentally pulled the wire loose on the oil pressure switch. Just check it to see if it's tight and not broken or stretched..Always try easiest fix first..

What OBD Codes do you have
& why would you use it, with any problem,
especially a known systems malfunction,
that give you a dash light

are there any codes on other then the overdrive. I had a few in my shop with a common distributor problems

Also- the rattle is most likely the valve lifters. The lifters on this engine and the model previous (I have owned both to 180k miles or more) lose pressure when the motor is off. They re-pressureize with engine oil after the motor starts and tap a little until they "pump up" to full size. Just don't drive until the rattle dies down and as long as it is under 30 seconds or so- you will be fine there.

the engine may be slugged up from lack of maintenance/oil changes, since the oil was black when you purchased the truck. was the light coming on before you changed the oil?? if not, try changing the oil filter for nissan one. if that doesnt do it than you can dump some internal engine cleaner into it if you want, but it may develop external oil leaks. the oil builds up a film after a while inside of you engine. if you wash it off, the engine may start leaking oil. to really diagnose this, you should take oil pressure reading at the oil pressure sending unit. you will ofcourse need some specialty tools to do this job such as pressure gauge and oil pressure sending unit socket to remove it so you can screw the gauge into it.good luck.

The oil light comes on when there is no pressure. There is no pressure when the pump either cannot get oil to pump or has oil and will not pump it.

Get it checked before you do anything else. A engine running with no pressure is a cooked engine.

9 times out of 10 it is nothing. My engine light stays on. If it really bothers you then you can take it to any oil change place and there is a sequence that they do.`

The knock sensor is not a huge deal to replace and will not turn on the light. It should be dont though.

The crankshaft sensor is located directly between the engine and transmission. It is dead center at the bottom.

nothing,, that light is just a service light....a reminder that you regular maint is due soon...thats all..ur almost due for ur 30k major service

inner timing cover y shaped oil gallery gaskets..make your own or order the complete cover..costs from nissan are 500 canadian for the cover and around 1500 total for the replacement.oil pressure goes back up immediately after the install..alot of work to replace a cheezy piece of paper...