Should Tyres Need Blowing Up Every Week.

[pgp001]

My 4.2 seems to always lose pressure in three of the tyres, I pump them up to 30 psi and within a week to ten days they are down to 14 or 15 psi.

This happens on three out of four wheels, one seems to hold OK.

I have checked for valve leakage, so all I can assume is that I have three slow punctures (unlikely)

Or the tyres are leaking because of of rim corrosion, or the aluminium wheels are actually porous, the tyres have never been off in my ownership of 26 months.

Next autumn I will be getting a set of new tyres fitted ready for winter, it worries me that it might make matters worse once the tyres are replaced.

Any ideas please ?

Thanks

Phil

[Davrav]

Why not spray a weak soap solution round the rims to see if there are any obvious bubbles? The air must be getting out somewhere.....

[Cyker]

A few possibilities;

Slow puncture

Corrosion around rim (Inside or out) where it meets the tyre causing an uneven seal

Dodgy valve

Corrosion around valve stem

Loss due to kerbing/potholes

[FROSTYBALLS]

Have a look at this old Honest John topic for ideas - http://www.honestjohn.co.uk/forum/post/index.htm?t=65429

[Hoovie]

Given it is on 3 out of 4 wheels, I would say that punctures would be unlikely unless you are VERY unlucky or tend to drive on very bad roads.

Same goes for valves.

I would guess on one of the two following things ....

1 - corrosion pits/ debris around the rim preventing a total seal between tyre and wheel - needs the tyres removed to clean that up

2 - pot-hole damage - the weakest part of the wheel is on the inner rim where you can't really see without taking the wheel off.

I would be inclined to take off one of the wheels losing pressure and check the inside rim - I bet you will see a distortion :(

[The Striding Man]

Are your alloys badly corroded? The reason I ask is that my tyres lose pressure and I put it down to the alloy wheels being porous and over time lose air. (The wheels are very scabby)

I will be refurbishing mine and fitting new tyres, hopefully that should cure it.

[Big Kev]

Don't presume your alloys are actually refurbishable, mucker, as I found out to Hoovie's cost very recently when he came up and tried to do a friend's wheels. They too had been leaking air, but the corrosion really was past what he could fix, and he is no quitter.

I found friend great set of replacement alloys on ye bay, and her old ones are now onamental giant tea strainers....!!!

Send me some phoateez of yer alloys and will forward to Hoovie out of interest. He is now refurbing wife's TTE alloys.....watch this space.

Big Kev

[CharlieFarlie]

Corrosion behind the tyre beads is sometimes not so easy to spot and is very likely the culprit here.

The direct answer is NO you should not be needing to re inflate so often and so much pressure.. Safety is compromised you fuel consumption will go up and worse case scenario its an offence to drive with under inflated tyres... Best get em sorted mate ..

[Pogle]

I've read something about the area around the inside of the valve (where it seats onto the rim) being a problem for this age of Rav 4. Could that be then problem here?

[Hoovie]

Not heard that myseld, must admit.

any area that is subject to 'trauma' is a candidate for corrosion - and hence sealing issues. The valves are usually removed in a fairly brutal way with a hacksaw blade or similar. If the operator wielded the blade in a careless way, guess could have nicked something, but pretty unlikely.

Do you know if the wheels have had any refurbishment in the past? If paint comes into contact with the rubber of the valve, that can affect the valve and cause it to become porous over time.

[Pogle]

The bit about possible trouble re tyre valves is in the "what's bad" section of the review of the Rav 4.2 on the Honest John website. Someone might be able to post a link? Describes the alloys as becoming terminally porous around the valves.

[Hoovie]

A lot of the HJ stuff is, TBH, a load of total BS IMO (pops, ackynom city there! ). I think he also has warnings about DMF failures on the RAV 2.2D engines, but I don't think any instances have ever been mentioned on this forum?

[CharlieFarlie]

Anywhere moisture is retained in many things from roofs to cars will suffer in usually a detrimental way.. So retained moisture around the valves or beads could be the reason why they suffer..

That said the wheels could not have been of the highest quality and that I'm afraid is a seemingly common occurrence many Japanese cars..

All Japanese wheels will display the JWL symbol which is an industry standard but time seems to degrade them...

[bothwell_buyer]

check the wheels for leaks as mentioned above. You can get wheels refurbished at around £40+ a wheel. A set of new alloys would cost anywhere from £100 each.

I have a spare set but you wouldn't want them as they are fitted with 225/40x18 bald tyres for racing.

[firemac]

check the wheels for leaks as mentioned above. You can get wheels refurbished at around £40+ a wheel. A set of new alloys would cost anywhere from £100 each.

I have a spare set but you wouldn't want them as they are fitted with 225/40x18 bald tyres for racing.

The last time I asked Mt. T, he wanted £275 for one alloy for our 4.2!! Got all five refurbed for £300.