Chrysler Repair: oil pressure light flickers on, light flickers, stock reply

Question
Roland-I have 2003 Chrysler 300m 3.5 engine. My oil pressure lite comes on at times. It will flicker when driving,ans stay on.
Shut engine off, start engine and will work fine next trip.
oil is full,Had a similar problem with led's flickering on climate control+trans indicator concerning auto headlamp system.
                                                   Thank Dave


Answer
Hi Dave,
Here is a 'stock' reply I have given:
"This is fairly common with all makes/models. Your idle rpm could be a little on the low side which means the pressure is going to be low enough to turn on the light after the engine warms the oil, which also lowers the pressure a bit. The actual minimim oil pressure is 5 psi so if you wanted to check this out you could have it measured with a gauge at a shop or buy a gauge and substitute it for the oil pressure light sensor located next to the oil filter.
But in my experience I would not be concerned for the moment, but rather the next time you change the oil increase the 'weight' by one step*, which increases the viscosity and thus will raise the pressure at idle so that the light will usually not come on anymore. Another approach would be to buy a new sensor for the light and replace the present one which may be off-value. It is supposed to come 'on' when the pressure drops to 4 psi, and that is about the spec for pressure minimum at idle.  Either of those approaches don't have any labor charges if you do it yourself.
The only time you really have to be concerned is if the light comes 'on' and stays 'on' when you are driving and the rpm is higher than about 1,000 rpm as that could mean there is insufficient oil reaching all the moving parts and if so will damage the engine.
*If you are using 5W-20 move up to 10W-30 for example."

Don't drive at road speed with the light 'on' and you are going faster than idle rpm until you sort this out for sure. The pressue switch is on the driver's side of the engine, just in front of the oil filter. The port into which it is screwed is where you could also install a gauge to check the pressure. The minimum at 3,000 rpm should be 45-105 psi.
The flickering associated with the auto headlamps is to be expected at dusk when shadows sweep across the dash and cause a false light-dark reading on the sun sensor.
Roland