Losing Tyre Pressure - Alfa Romeo Giulietta Veloce 1.7 – 2018

[ricardo]

Have a bit of a problem which I am hoping some member can help me with.
My tyres which came with the car (Pirelli Cinturato P7 EcoImpact 225/40 R18 92W) are in good condition but are losing pressure. Pump them up  to (38 LB.) all round 'but' 2 days later they have dropped to 27-30LB. The tyre sensor is adjusted after pumping up and the caps firmly screwed home.
All I can think of is: rims have been damaged, tyre sensor..........? Do I go out and have 4 new tyres fitted? Thank you.

[poohbah]

Its odd that all 4 tyres are going down, are you sure the tyres actually are deflating (are the lower readings from an external gauge? Maybe try a different one to confirm deflation is real). For all 4 to be deflating would be rare unless you'd just had new tyres/tubeless valves fitted - incorrectly so not properly sealing.

You can try spraying some detergent or similar around the base of the valves with cap on - if it starts bubbling, will indicate valve is leaking where it goes into rim. Also take the cap off and try the same test in the top of the valve. You can do the same test around the rim where the tyres seal into the rim - but need to take wheel off to check inner and outer sides.

I'd just head into my local tyre shop and ask them to check, its not something you're likely to be able to fix yourself anyway.

Also I assume that your rims aren't 3-piece? Over time some of the fasteners holding the centre, outer & inner rim together can degrade or shear off and the rim will no longer be able to properly seal. But weird all 4 would go at same time unless you've recently done something unusual like drive over ultra-rough boneshaker gravel for miles. Worst case scenario is that rims are cracked.