Astra K - tyre pressure

factor29

One wheel is slowly losing pressure, around 7-8 psi over the course of a week. I've had to repump several times.

I took it to a tyre fitters to check for a puncture, but no problems found. They resealed and suggested that might be the problem - it wasnt. 

I've had a TPMS issue on another wheel previously, but this cost £100 at the time, that I'd rather not pay if I can help it. I found Halfords do TPMS servicing which replaces the valve leaving the TPMS sensor in place. However, the wheel is still losing pressure. Surely the sensor itself cannot cause a leak as its internal only, and the valve etc which is internal was replaced? 

cymruchris

How old is the car? Are the wheels Alloy?

If the tyre is proved to be sound, and the valve decent - then another possibility if the wheel is alloy is that it's become porous and/or has a corroded or damaged rim and air is escaping through one of these factors. (It's rare for a porous wheel to lose that much pressure in that much time - so might be more inclined to think it's the rim against the tyre seal)

What's the overall condition of the wheel? Has it had much kerbing damage over the years?

If the wheels are reasonably decent - it might be worth getting them refurbed if their getting on a bit.