Vauxhall Astra

[MORELLO]

Anybody know how urgent it is to change the O2 sensor on a V-reg 1.8 16v Vauxhall Astra? The engine management light is on intermittently and I've been informed that unburnt fuel entering the catalytic converter could be expensive. I've just shelled out for new brakes all round, service and cambelt , so cash is tight.

[Hippy]

Cars are fitted with a clever wallet sensor. When the wad bulges (holiday money, Xmas spending trip etc. etc.) a little something, say an indicator lamp, will blow. You struggle on for a couple days and then relpace the bulb. Whapumphhhhhhh, and down goes a tyre, and no sooner have you got that fixed when Twong-plunk there goes the clutch.

About the same time you accidently leave the boot lid open and flatten the battery as there is a nice courtesy light in there. Guess what, the battery won't hold a charge any more. It is, of course the depth of the coldest snap in five years and you have to trudge to the garage for new parts.

Only when the wallet sensor is truly satisfied that all folding stuff has been spent, cards are banging or beyond their limits, and you have humiliated yourself with all your friends by being late, or not turning up because of car trouble, begging lifts and favours, and have taken out lifetime subscriptions to "What Car" and "Motor Buyers' Weekly" will the darling car stop asking for more expensive parts.

The joys of motoring.

P.S. Your Insurance is about due now!

[BillyNoMates]

Are you certain it is the Lamda or Oxygen sensor ? It is relatively easy to replace but because of where it is (exhaust manifold), and the time it will have been there, the threads may be rusted up. Depending on the age, mileage and type of sensor, it is quite possible not to be working well. If you have a diagnostic socket, you can buy a very simple device from Halfords (about �10) that will interogate the engine management system and give you an indication of what the problem is. You are quite right that catalytic converters don't like unburnt fuel - it basically poisons them. But you may find that you have a bad air flow sensor or bad plugs. Good luck