Kaiser40

I have had my 2023 GLE 63 for 2 weeks now.
I checked the readout for tire pressure and it read 44/42 front and 38 for back tires.
After letting it sit overnight in my pole barn it has climbed to 50/48 front and 44/43 rear.
Temps have been mid 80’s here in Minnesota. Regardless this seems too high. I have not added air so I am wondering why the pressure climb?
How would you be able to adjust pressure if the outside temp affected the reading?
Inside the gas cap I think the indicated pressure is 42/36.
I have not tried manually checking pressure, just what the vehicle shows on MBUX

mbwillgrubs

Pressure increase is due to the temperature increase. PV=kT where k is a constant. T goes up, V stays constant, P goes up. It is due to the increased kinetic energy of the gas molecules in the tire. I would just go by the pressure chart on the fuel filler lid. One has to adjust when the temperature changes significantly. Hope that helps.

W205C43PFL

That is a good explanation appreciate it and ill add: OP only inflate tires when tires are not driven or sitting overnight just as a reminder, like how you are now.

Kaiser40

This is the reading today after sitting for 24 hrs in 40 degree temperatures. I will check tomorrow and adjust to 41/36 as cap cap indicates. Thanks for your input.

W205C43PFL

Just want to follow up with you OP, all good now?

Kaiser40

Tire pressure all good now …. Thanks! Now I gave another problem as the glass roof panel between the windshield and sunroof shattered!

W205C43PFL

I am sorry about that, any chance your insurance will cover that?

Kaiser40

Dealer said a rock hit it…. although no one was in front of me.
$1300 repair/ $500 deductible

W205C43PFL

Ugh sorry, luck of a draw I guess hopefully your experience is better.

Kaiser40

$1300 repair! Got it back yesterday…. 2 day turnaround

W205C43PFL

Sorry to hear that : (