Hello all, I've been having problems with all four of my tires losing air quickly in my 2004 Prius. I filled them up 3 days ago to 36 in the front and 34 in the rear instead of 35 and 33, since I knew I was just going to be filling them up again anyway. Three days later, my front two are down 6-7 psi and my rear two are down 4-5. I checked them both during the afternoon and I live in hot/humid Pennsylvania. The front two tires were replaced 13 months ago at a Toyota dealership by the previous owner so I find it a little odd that the new tires are losing air quicker than the older tires in the rear. I did check out the other posts relating to losing air in the tires but I wanted to see if there were any recommendations that were not on the other posts. Should I just try out some leak-checking methods for each tire and then get it patched or fixed? The car just passed state inspection last week and tire tread is fine so I would prefer not to buy new tires until the tread goes bad. Thanks for any information! Edit: The two new tires were added about 8,000 miles ago, and I use a good tire gauge to check them.
Maybe the TPMS are mis-installed or old? But in hot weather the air will be warm you add to the tire, top em off and make sure still leaking. Use soap solution to check for bubbles. Toyota TPMS seem robust but Chrysler (my minivan) corroded out and leaked...quite a safety issue as they would fail at high speeds. But who knows what TPMS make you have in there now, My new RAV4H the pressure is higher now that when I bought in March and I have not touched it. OK you have 2004 no TPMS until 2006...soap it
You might be fooling yourself here. IF.....you are adding air when HOT and seeing them low the next morning when COLD.....you are doing it wrong. Air them up when COLD. And check them again the next morning when COLD again. If you do have a TPMS, get them to the right pressures and then "reset" the TPMS. Does the vehicle have after-market wheels by any chance ? IF you really ARE losing air in all 4 tires, which is highly unlikely, you need help from a good tire shop.
I do not. I live in the suburbs so just flat roads and hills. Alright, thank you. I have seen there is an external TPMS sensor that I could buy to monitor it but I haven't looked any further than that. I will definitely give the soap a try! I was adding in air during the afternoon and then checking it in the afternoon. I'll try adding it in the morning instead. The 2004 doesn't have a TPMS but I may look into getting an external one and seeing what that does. The wheels are OEM and I believe they are the same ones that the car came with in 2004, since there is no mention of new wheels in the service history on the Toyota Owner's website. Thanks!
Not sure if you replaced all the valve stems on your last tire change. Many shops will put in new valve stems to prevent problems like you're experiencing now. Also the tires can get dirt trapped in tire seal between the rim and tire. So you can try removing the tires and cleaning the rims thoroughly and then reinstall.
It doesn't really matter when you add air, but is does matter when you check it. If you don't have an tire inflator at home, add air to about 8 psi above your target cold pressure, and then bleed them down to the target pressure the next day before you drive the car. Don't exceed the maximum cold pressure on the sidewall. Check them again the following day(s) before you drive to see if you are losing air. If you have an tire inflator at home just air them up when the tires are overnight cold and check them the same way on subsequent days. If they're still losing air it I'd check the valve stems and cores and then look at the wheels for dirty or bent rims.
I'm not sure if the valve stems were changed since it was done before I owned the car. They had the work done at a Toyota dealer so I assume the dealer would have replaced the valve stems.
I would check if the valve stems (the valve inside) is actually tightened properly. The techs that does the oil changes and tires are usually not trained mechanics. Any tire shop can check the valve tightness for you, it's a turn of a screwdriver type of tool, takes 1 sec per tire