About a week ago i changed the oil in my car, i was running about 32 33 oil pressure but iv noticed that when the car gets warm my pressure drops to almost in the red, anyone know why? i know i hae alittle more oil than needed but that was my fault, i put in a full 5 quarts but that shouldnt effect it should it? this is really starting to bother me..also might add that i just replaced the oil pressure switch aswell about a month before i changed the oil and put on a new filter.

 

Before you get worried you need to check the pressure with a mechanical gauge. My dash gauges are not accurate because of their age. I read low on oil pressure on my dash but not on a mechanical gauge.

 

Also, I forgot to mention... Overfilling the oil can be very bad and cause damage that you do not want.

 

its not that much over, just alittle over the full mark, also my gauge was working perfectly before i changed the oil

 

could a big oil presser switch do this aswell? when i got it zone didnt have the normal $6 sensor so i had to get the huge $23 one, so could this do it?

 

My car does this as well. Its done the exact same thing for years drops when it warms up. My speedo and odometer quit working as well so I always asumed it was because of the age the gauges stopped working right.

 

I generally overfill by a half quart. I take lots of high-g corners in my car. Nothing reckless I just put a lot of money into handling and want to enjoy it. A lot of corvette guys overfill their Gen I and Gen II sbc's by a quart when they go road course racing because the oil sloshes to the side and starves the pump/bearings. But by extension tehy only do this when they're racing so take from that what you will. But it's a poor man's way to get around not having a road race oil pan.

Your switch isnt the same as as the oil pressure sending unit. The switch is for the fuel pump. The sending unit is for the gauge. I wouldnt fret until I replaced the sending unit. If its a new sending unit then I would replace it again - it may have gone bad.

My old sending unit failed suddenly after reading very normal readings for years. My new one reads way off from what the old one did and over the past 3 years has given me more and more erratic readings. Sometimes my idle pressure is 25psi, sometimes it's 40 psi at the same RPM and coolant temp, sometimes within the same 10 seconds. Electric senders and old gauges just arent that accurate so dont worry too much.

 

Overfilling the crankcase increases crankcase pressure and can lead to oil leaks. If you worry about oil pressure loss on hard cornering, install a road racing oil pan with trap doors and added oil capacity. I love to corner hard and my beast is built to do it with the best of them. I run a stock oil pan and have never had an issue.

Oil pressure is directly affected by oil viscosity (the thickness of the oil) if your oil pressure dropped when you changed oil, I would suggest that you probably went to lighter oil. Go back to whatever was in the motor before.

As main, rod and cam bearings wear with mileage, oil clearances increase. This will reduce oil pressure. Running a slightly heavier oil will restore this lost pressure. I often recommend going from the factory installed 5w-30 to 10W-40 after 100K miles.