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New Rc350 Fsport Losing Air In Tires

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Been having my new RC350 three weeks now. Three days after driving her home, the low tire pressure light came on. Sure enough, two tires (both on rear wheels) were three pounds low, so I aired them up. Checked the front tires and both were about 1-2 pounds low, so I figured dealer had not checked them carefully before delivery.

Last week (car is now two weeks old), I checked inflation on all four tires just to make sure their pressures were stabilized and both rear tires were under inflated again, driver side by 3 pounds and passenger side by 1 pound. Again, I brought them up to 36 pounds with my compressor.

Today (car is now three weeks old), I checked them again and rear tires were low again: driver side by 4 pounds and passenger side by 3 pounds. Both front tires were about 1.5 pounds low. Again, I inflated all tires to standard pressures. By the way, all pressures were checked via a digital, calibrated gauge after the car has been idle for 3 hours or more.

New call next week will be to Lexus toll-free help line to see if someone locally (maybe the local Toyota dealer) can remount all tires for me- saving me a 1 hour & 15 minute drive to my dealer in Baton Rouge, LA. If I cannot get local warranty service, I guess I will have to take the long drive and have my dealer do it for me. I am reluctant to PAY for someone to do this for me.

By the way, I had the same experience with the second ES350 I bought some years ago. A local friend who owned a service station remounted all tires for me at almost no cost, but he is no longer the business owner of that service station.

As a matter of history, I am on my sixth Lexus in the last 9 years: 2 ES350's, 3 GS350's and now an RC350. Damn, I love those cars...

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Hi Larry,

This would be a frustrating problem. In reading your summary I didn't see any mention of talking with your dealer for an explanation or rotation of tires or a solution to your issue. If you have not been able to get any help from your dealer, going to Lexus makes sense. If you haven't worked with your dealer, that's the first thing Lexus Corp is going to tell you to start you with your dealer.

When you fill your tires do you reset the "tire low gauge" , or do the tire low lights even come on? I believe but I'm not certain that the new models do not have to be manually reset. By the way, does the tire pressure sensor work with the spare tire.


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I did not mean to mislead readers by my comments on this matter. My first call to Lexus toll-free number will be to see if I can take my car to the local Toyota dealership to remount the tires, saving me an hour and fifteen minute drive to my dealer in Baton Rouge. If that phone call insists I return to the dealer, I will then call for an appointment.

Here is what I have done to back up my assertions: For the past two weeks I have not documented exact pressure drops, but as a full-fledge type A personality, I started doing this on this past Sunday, recording exact pressures digitally at all wheels. I repeated this today, Tuesday, and will do so every other day until my first opportunity to take it to any location for remounting. That visit, due to work, cannot occur until next Monday, so I will have some 5 readings by then.

Note- all readings done after car has been idle for 3 hours or more and with a digital tire gauge.

Thanks for your observation in this matter- after this is all over, I will post final disposition of this problem.

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I have noticed, via the instrument display, that my tire pressure varies between 34 and 39 PSI during driving. My only salvation is that I know that people that own these TPI cars when they get older are in for a nightmare. My mother has a new Civic EX-L and has constant problems with sensors.

I have also found that many digital tires gauges are junk. I use a $18 analog gauge. The $39 digital gauge was all over the place. What does the car computer say about the pressures?

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I place no value on the instrument panel TPI readings- they can vary by a pound or two sometimes. What I do value is the total agreement between my analog and digital instruments. Yes, during driving, pressures will rise according to tire temperature, actually rising to what should be the idle readings & this repeated underinflation readings are not acceptable.

Thanks for your comments as they are well stated.

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Proud to say this scenario is over. The two front tires stabilized in pressure as well as the passenger side rear tire- all holding pressures up to specs. Went to local tire dealer to have rear driver side tire checked & they found a nail in the tire, thus identifying the problem of daily pressure drops. Having that leak repaired, I am confident this problem what NOT one of improperly mounted tires, but a nail picked up as early as on my trip back home from the dealer since my pressure was unstable from day two of ownership. I consider the matter resolved and this thread is terminated.

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