Lets hear some of the reason this happens... mobil 1, 5w-30 w/ PureOne filter, oil is not low, i just checked it. It happens after the car has more than warmed up, and only at idle.. I don't want to jump straight to piston rings, so what else causes this mess? thanks

 

The light flickers (or comes on) when the oil pressure drops below a threshold level. Many things can contribute to this.
- Your oil pump seals may be getting old.
- Your oil pressure sender may not be sensing pressure as it should.
- You are using a synthetic 5W30 oil. For warm season operation, this may be a bit too thin. You might try using 10W30. Additionally, synthetic oil tends to exert a little less pumping resistance and thus exhibit a little bit less pressure due to its flow characteristics. I used to only use 5W30 synthetic for extreme cold weather operation and even for that, it really wasn't necessary. Last winter, I just left the 10W30 in there.
- You may have a faulty filter that doesn't flow well. I kinda doubt this, as Pure ONE is a leading oil filter. I've been using these for years in my S.
- You have an unusually low idle, thus making for slower oilpump speeds and lower pump pressures.

 

[QUOTE=xviper,Jun 6 2006, 02:37 PM]The light flickers (or comes on) when the oil pressure drops below a threshold level.

 

Without know how many miles you have on the car and how hard you drive (ie. everyother shift is at 9000 rpm) we really don't have alot to go on. I would say that you should try xviper' suggestion about the oil weight.

 

Not sure how this would affect oil pressure. The oil pump pumps the oil to the top of the block where the sensor detects the pressure. The bearings would almost have to be gone before enough oil would escape to divert enough pressure away from the sensor.

 

Worn rigns will not cause the oil light to come on. If the pressure at the switch is below approx 4psi the switch closes and turns on the light. Oil pump output is it's lowest at idle. As engien speed increses pump output increases greatly.

With oil pressure this low continuing to run the engine will damage it.

Possible causes:
switch is faulty(not likely)
Oil filter is clogged
Oil pump pickup is blocked by some type of debris
Main and rod bearing clearance is great enough to bleed off lots of pressure
Oil jet is broken/loose causing internal pressure leak.

 

On my wife's Nissan it was caused by a faulty oil pressure sending unit.

 

Im taking it to my mechanic tommorow to troubleshoot these issues. Thanks for the input guys, I'll update this tommorow when I get back.

 

Whatever is is... its NOT the oil.
At operating temp both 5W-30 and 10W-30 are acting like a 30 weight oil.
They may not be at the exact same visc, but within a small percentage of eachother.

 

This is not necessarily true. When companies make multigrade oils, there are always compromises. It has been discussed here on a few occasions that at "operating" temps, a 5W30 synthetic motor oil is just slightly thinner than a 10W30 synthetic oil of the same brand. This small difference may be enough to cause the oil light to flicker under extremely hot temps and low rpm. At this present time, it can't be determined if the OP's engine has any other inadequacies.