I was wondering if this happens to other TC owners or just me....my front tires each lose about 4lbs of air every couple of weeks. I don't think I ran over anything as the PSI is the same for each side.
I just think it's weird that my fronts are losing a lot of air but always have the same exact PSI.

 

When are you checking the pressure?

You should always check after the vehicle has been sitting for a few hours and the tires are "cold" - in the morning before you go anywhere is usually best. When they're cold, your tires should be at the recommended pressure (32psi front and 29psi rear).

So could it possibly be that you're checking them at times when they're hot and cold? That could probably give you 4psi or so difference if you check them when they're hot... then they're lower when they're cold.

 

yeah.. something not right there for sure. As mentioned be sure you are checking them at the right times.

And ack... you know part of that wish list in your sig could easilly be taken care of.... I just happen to know this guy....

 

Haha... ya, I'm working on the $$ part of it actually. I have a quote from mr. garage1217 for a blue/white two tone with some red needles. I'm really hoping for next week, but I don't know yet.

 

another thing that can cause this "Effect" is the outside temperature. for every 10 degrees the temperature goes down, you "lose" 1lbs of air (1 psi). The reverse also applies, 10 degrees up, 1psi higher.

if it's 60degrees at night and 90 during the day when you check a "cold" tire, one that hasn't been driven. You can see the PSI change by 3lbs (3psi)! (30degree difference = 3psi) Now take that into consideration when you check the air pressures.

Also you may notice that the lower profile tires of the tC are more sensitive to these temperature changes. It's because of the lower sidewall. More sensitive to air pressure changes. Hope that helps

 

what tires do u have? my stock potenzas seemed to not hold air very well...specifically, one tire would constantly leak down to the low 20s and hold there.

i think the tires are crap and might be defective.

 

I have the stock yoko 17s. I always check the tire pressure when the tires are cold and when my tire pressure sensor light turns on.
For the outside temp issue- wouldn't the rear tires reflect a lower PSI as well? Because they don't. It is only the front tires that the sensor light goes on for.

 

I have a slow air leak too but its like i fill air once a month.. And yea when you check or fill air make sure its pretty much same time of the day or same temperature or else your tire gauge will be playing with you..

 

yes outside air temperature would affect ALL the tires. So if the rears are holding fine, but the fronts are causing the tire pressure sensor light to come on, then yeah you most likely have a slow leak. definitely have a tire shop or the dealer check that out.

the sensor light is for any tire on the car, front or rear.. doesn't matter..

 

I knew the tire sensor would light up if there was even 1 tire low- that's why I check them all when it comes on- and to see how many tires I need to fill up. It's just odd that it is always the front 2 that come up low with matching PSI.
I've had the car for a year now (same tires) and this has just started happening within the past couple months. I get the tires rotated every oil change at Toyota's Service Center and they haven't said anything about the tires needing to be replaced/repaired. I'm due for service this weekend, should I mention something when I go in there?

Thanks to everyone for trying to help me figure this thing out btw!

 

yeah i'd mention it to them, let them take them off and put them in the water tub.. or better yet, if you took a water spray bottle (like the ones for plants).. and sprayed water around the lip of the wheel (where the tire meets the wheel).. see if you see any bubbling up.. might have a leak around the lip..

but wouldn't hurt to mention it for them to check it out too.. definitely keep us posted. this is interesting, i mean one tire, okay a nail or something, but both.. hmmm.. odd.. but stranger things have happened..

 

Update- The Toyota service guys took a look at my front tires and couldn't find anything wrong. They checked the valve stems, tread, and where the tire meets the rim...nothing. So I guess I will just fill up my front tires whenever my sensor light comes on.

 

have you tried the suggestion i had about spraying water around the lip of the wheel? did they do anything like that?

 

dude losing air in two weeks is no way normal, they should be able to find out the leak, getting new tires may not be covered by warranty, unless the sensor is the problem they should be covered..

 

Sciontc_mich- I wasn't in the back when they checked my tires so all I have to go by is what they told me. It sounded like they did a thorough check...
I washed my car yesterday and squirted the tires (they are on the rear now as they were rotated) and no bubbles anywhere.

Ace- I don't know if it's covered by warranty if Toyota can't find the problem. Plus my tires have a lot of tread left so I'm not too anxious to get new tires right now. I don't think the sensor is acting up cuz when it comes on my tires are actually low.

 

yeah just trying to cover the obvious. you know maybe it's just that the tires suck? lol.. I know it's funny but I'm serious. I had tires before on other cars that they were constantly losing air. Didn't stop til i got rid of them. Maybe that's the case here too.

maybe chart how many lbs of air you lose a day? if you're into wanting to put that much into it.

 

^^ Thanks for the ideas. Obvs or not you never know what a person overlooked or how much 'car knowledge' they have...I really do appreciate all the ideas and help provided!
Now to see if my sensor glows again which tires will be low...rear or front....or both this time!

 

Try giving it sometime now that the front are now at the back if the same tire loses air then its up to you if you wanna get new tires, and there's no damage in the rim right?
I too have slow air leak but didnt bother to have it checked coz i only add air every 3-4 weeks..

 

One rim has a very slight nick, nothing ugly and the tire itself is unscathed.
If my sensor goes off again I'll decide on what to do depending on which tire is low. Which will probably be to just keep putting air in them until I need new tires .

 

I wouldnt just accept the problem. Take it to an actual tire shop, such as Goodyear (shameless plug). They will inspect tire by placing it into a water tub to see if there is a leak anywhere. You may have a small pin hole causing a slow leak. Typically Goodyear will not charge you anything if they do not find a problem. If a flat repair is needed then the average cost should be $21. The TPMS sensors also cause problems from time to time, and if that is leaking the dealer will need to pay to replace it for you.