Elise rear tyres go flat

[Tim3003]

My Elise (S1) spends most of its time in the garage, and the rear tyres now lose all their pressure over a few weeks of inactivity. This started with one tyre, now it's both, so it cant be punctures. Any ideas what is causing it?

When I pump them up and run the car it's fine. It takes weeks for them to go down. The fronts dont seem to have the problem. All the tyres are low mileage and about 4 years old. The wheels are spotless and black, so no corroding alloy problems I don't think.

Thanks.

ps: I took it to ATS and they wouldnt jack it to check up because the jack-points are all hidden under the all-covering underbody guard! That little diagram of them in the manual is useless!

[kambites]

I suppose either the wheels have gone porous or the valves have gone.

[Russell Mc]

Could be corrosion on the rim making the seal on the bead not great

[Toaster]

Just get some soapy water place in the tyre valve and see if it blows bubbles same for the rims it's an old fashioned method but works

[Pabl0]

Sounds like a leaking rim.

[Toaster]

Possibly, but if the tyre valves are old its not unknown for them to deteriorate either within the valve or between the rim and valve. First step take the valve cap off, use the soapy water and watch for bubbles. then check the base of the valves then between the seal between the tyre and alloy. Anything other than testing for leaks is at best a guess (hope I don't get flamed for that) just check check and check again. Its no different to finding a slow leak on a bicycle wheel.

[kambites]

Pump it up then submerge the whole wheel in the bath and see where the bubbles come from.

This might not be a good idea if you're married.

[Thorburn]

You'll need a big bath too. I'd take it to a local swimming pool and chuck it in when no ones looking.

[Captain Muppet]

Thorburn said:

You'll need a big bath too. I'd take it to a local swimming pool and chuck it in when no ones looking.

If it's only leaking in one place you only have to get that one place submerged to find it. You can do a rear wheel in a normal sized bath if you rotate it occasionally.