Tire pressure - gradual decline...

[SVS]

Hi - I've had my car for a bit more than a year, and have had to fill air in all four tires two times. Each time the pressures have gradually declined till it was noticeable, over a period of 3-4 months. I've been filling them up to 38psi as recommeded by on the fuel tank lid. Last time around they had gone down to 27 psi.

Anyone else experience this? Any ideas why, and possible solutions?

Thanks in advance!

 

[realcyberbob]

Not to sound like a jackass, but....is this your first car? It is normal...

 

[RacingManiac]

They vary with ambient temperature too....

 

[grambles423]

Yeah, we can go into the molecular principles of it, but thats not needed.

Its going to happen.

 

[RacingManiac]

They vary with ambient temperature too....

 

[grambles423]

Yeah, we can go into the molecular principles of it, but thats not needed.

Its going to happen.

 

[Marvin]

However unexplained losses can be due to leaks around the tyre beads, Shrader valves and worse still a porous alloy casting.
However as this applies to all tyres then gradual loss is inevitable. In a country where you have seasons then there is going to be an observed change in pressure due to temperature variations especiall if you pump up your tyres when it is hot and then wonder why the pressures have dropped when the weather gets cold. Perhaps not in Abu Dhabi, though.

 

[mark986]

Try filling then with nitrogen. If you need to fill your tires within the same timeframe you do now, something is wrong.

 

[Jacuzzi]

I would suggest checking your tire pressure monthly...if you're running the Detroits at low pressure you might be buying yourself a wheel sooner rather than later if you smash a pothole. With the sidewall as small as it is, you need the PSI. That's besides all of the other reasons to keep your tires inflated (crappy wear, worse fuel economy etc)

 

[flug2012]

I hope you checked it more than twice in a year... Check them when they're cool (in the morning) fill them to 38-40. Check weekly after that, only takes a minute. If you you continue to see pressure loss, replace valves or have tires reset on your rims (clean beads).

 

[Bender1]

Try filling then with nitrogen. If you need to fill your tires within the same timeframe you do now, something is wrong.

Not to start war but advantages of Nitrogen fill is largely myth on street cars.

 

[leiito1]

Fill them with nitrogen!!! they'll never leak and you'll lose 6 lbs on each tire!

 

[Jacuzzi]

Not to start war but advantages of Nitrogen fill is largely myth on street cars.

Bender, you know this is a lie. You know how much of an effect increasing tire pressure due to heat can have over a qualifying lap :lol:

 

[SVS]

Thank you all for the helpful replies!

A colleague at work with a GTI of almost identical specs and vintage has also been experiencing this. Maybe its "normal" for this tire profile, and may also have something to do with the generally hot weather around here.

BTW, "Realcyberbob", your reply was funny! This happens to be the only car where I've experienced a noticeable decline in such a short period. In all previous cars, and the Prado which the wife drives, I've checked pressures regularly, and never had such a noticeable decline in such a short time. The Prado's tires easily go more than a year with no change in pressure.

 

[Marvin]

Again, I say porous Aluminium castings!!!