I went to air up my tires and the gauge said 40 PSI, so I stopped filling it up with air. I got into my car and checked the psi from the system and it said there was 51. Do I need to let out some air or is it okay to leave that much air in my tires?!
No it is not Okay. In your manual or the plaque on the drivers door frame will tell what the tire pressure is supposed to be .
Tire pressure is normally around 30 psi in most cars
I would get a high quality pressure gauge and check the calibration of every other gauge you are using. There should not be that much discrepancy.
That is not really good advice . Some vehicles have different pressure for front and rear . I have 36 on one vehicle and 32 on another .
Simple thing is don’t guess and go by the door plaque , period.
My own rule of thumb is 32 psi in the absence of any other data. My experience is that shops tend to overinflate tires by 4 psi or more. I always check new tires to see if there’s a discrepancy. Back in the day–1970’s or so–it wasn’t unusual for the Owner’s Manual and the recommendation of the tire maker to disagree, for example 32 psi vs. 36 psi.
If the car has been driven into the shop and the tires are warm , if thetires are not being changed,the shop should overfill by about 4 PSI. The number on the door is for cold tire pressure.
What psi did the dash say prior to going to gas station? You went there for a reason. Now the gauge you used does not match dash? Are both right?
I’d go to dealer and ask service writer. He might give you a dirty look.
Most tires I have had in the last 20 years are around 35-36 psi . Yes go by the door placard . Get a good guage . Most tires have a max of about 44 psi unless you are talking speciality tires . If it is almost 50 then let some out before you damage or blowout the tire . My external guage is within 2 lbs of the dash reading on the car .
If the gauge you mention is one built into a gas station compressor, keep in mind that those are notoriously inaccurate, so I’d go by the TPMS for now. However, as already mentioned, get a good tire gauge for double-checking the TPMS. I prefer a mechanical dial-type gauge from a reputable brand such as Accu-Gage.
The inflation pressure for your tires is 35 psi, front and rear. See page 8-5 of your owner’s manual.