Hi guys! Not too long ago I filled all of my tires with nitrogen at my local Lexus dealership, they filled all four tires to around 35 PSI. I drove it straight home and since I dont daily my F I didn't drive it for about 5 days. When I started the car I realized my PSI on my front driver tire was 22 and at the time when I would drive it the PSI would slowly go up to about 27. I went to a different dealership after work one day (because its closer to my job) and they couldn't find a leak of any sort and they assured my it wasn't my TPMS. All they did that day was completely empty the tire and refill it with nitrogen but the problem continued. I started my car up yesterday for the first time in over 2 weeks and noticed my PSI was lower than its ever been, 20 PSI. I went to my local dealership again today and told them the story of what the other dealership did but they said the same thing to me - they can't find a leak anywhere and its not the TPMS. At the end, they ended up filling it to 38 PSI and told me if it continues to drop bring it back in tomorrow. I know it will, which is the most frustrating part. Does anyone have any knowledge about something like this? Any help would be greatly appreciated. Thank you!

 

While Lexus recommends N2 for the RCF, I have never filled up Nitrogen in my RCF. I have an air compressor and use it to adjust tire pressure. If it is decreasing in all four tires at the same time then I highly doubt it is a leak. Nitrogen does have a natural tendency of losing pressure in the tire, but definitely not like it is not like you are experiencing. Nitrogen is dry so I am wondering if the gauge is misreading it? Maybe, try using a standard digital air gauge and see how the psi on the gauge compares to what the RCF's tire pressure monitor is giving.

 

I thought the nitrogen phenomena had passed Remember the air we breath is 80% nitrogen. But, as I recall one of the supposed benefits of nitrogen was that it would maintain pressure longer before needing to be refilled. The last time I had nitrogen in my tires was when I bough my ISF 12 years ago. My LC came with common ol breathing air But that really didn't matter because I soon chucked the stock wheels and tires

As fas as a home compressor. I have one mainly because tires should be refilled when cold. If you go somewhere else to top off your tires, they will be hot.

 

Unless the TPMS is defective you have a leak...have you tried measuring the air pressure with a tire pressure gauge?

 

The only thing you get with an N2 fill is no water vapor. Your home compressor includes whatever water might be in the compressed air, and if there is a lot of water in the air when it is compressed you'll have some weird pressure rise when the tire gets race track hot. With dry N2, you'll have very consistent pressure rise (usually a whole lot less than whole air with water vapor in it).

So, if you want to get to the bottom of this and actually find what is leaking (because that's what is happening) just put regular compressed air in it and watch the pressure drop just the same. I wouldn't be surprised if you have a cracked rim or a loose valve stem.