Oil pressure gauge

I had the oil changed recently in my 2008 tundra 5.7 v-8. I noticed the oil pressure gauge moving. When I started the truck, I noticed the gauge will move to the right of the indicator in the middle of the gauge and then it will go back to the middle mark on the gauge when it is warmed up. I also notice that it moves a little when I accelerate. Maybe it has done this in the past and I just have not noticed but was wondering if I should be concerned.

It more than likely did this in the past. Oil pressure goes up & down a bit normally. E.g. it should increase some when you accelerate. Cold oil is thicker than hot, so your pressure would tend to be a bit higher cold. There are probably red zones at each end of the gauge’s scale. That’s where you get concerned.

The oil pressure will be higher when the oil is cold and thicker.
Plus, the pressure will rise with RPM until it’s high enough to open the pump bypass valve.
It’s all normal.
Be happy you have a real gauge that shows what’s actually happening.

If this started occurring after the oil/filter were changed, a defective oil filter may have been installed.

Oil filters have a by-pass valve. This by-pass valve allows oil to by-pass the filter media when the engine is started cold because the oil is too thick to pass thru the filter media. So as not to starve the engine of oil during a cold start, the oil goes thru the by-pass valve. Or, if the filter media gets so restricted where oil isn’t able to pass thru, the by-pass valve opens preventing the starvation of oil to the engine.

I would replace the oil filter to see if a defective by-pass valve in the installed filter is causing the erratic oil pressure gauge reading.


Thank you for your information.

Did you put the same viscosity of oil in the truck at this past oil change? If the oil is a higher viscosity, it will be thicker when it is cold and the oil pressure will be greater. I remember in the days of singe weight oil, the 1954 Buick my dad owned in the late 1950s the oil pressure gauge would go almost to the extreme high pressure mark when the car was started in cold weather. The car always registered high oil pressure on the gauge, but in cold weather the reading was very high. I do remember once when the oil pressure didn’t register as high, but was still in the normal range. We had driven quite a few miles before changing oil and the bypass valve had opened on the filter. After an oil change with a new filter, the gauge again registered high.