Why do my tyre pressures keep dropping?

I am losing pressure from three of the tyres on my Ford Fiesta 2014. I left the car unused for four weeks and the tyres reduced from 30PSI to about 20PSI on three tyres. Two of the tyres were fitted about six months ago including new valves.

Asked on 14 October 2019 by robjudi

Answered by Honest John
It's one of four things: Slow punctures in all three tyres (unlikely); faults with the valves; damaged rim seals or cracks in the alloy wheels allowing loss of pressure. Start with having the tyres re-sealed. If you're still having trouble, replace the valves.
Similar questions
How can I stop my new car tyres flat spotting during the Coronavirus lockdown?
I inflated my car tyres to the correct pressure of 30 PSI and my digital pressure gauge showed 30 PSI. Six days later I checked them and using the same gauge the pressures had increased to 31.5 PSI. Is...
I have a 2009 Jaguar XFR. 12 months ago the tyre pressure warning came up on the dash. I pulled over and checked but the pressures were fine. Since then the fault has repeated frequently, always in motorway...
 

Ask Honest John

Value my car