MOTORISTS with older cars could find themselves stranded as garages cease stocking Lead Replacement Petrol (LRP) following a fall in demand, a local filling station manager has warned.

LRP was introduced in January 2000, as part of a European strategy to replace four star leaded petrol and so reduce traffic pollution.

But already demand for the fuel is dwindling. All petrol-engined cars built since 1993 and sold in the UK are now manufactured to run on unleaded fuel, which has resulted in falling LRP sales as older cars are scrapped and replaced.

For older cars, lead or its substitutes in the petrol coats the valves in the engine, lubricating them. Continually running an older car not designed to use unleaded petrol will eventually cause the coating to wear away, causing damage to the valves and cylinder heads.

According to the AA, sales of LRP have already dropped to as little as two to three per cent of all car fuel sales - meaning many filling stations are beginning to phase them out altogether.

Rural motorists with older cars that run on LRP will begin to find it increasingly difficult to find somewhere they can fill up, the organisation warns.

Nigel Clayton, regional sales manager at Benfield Ford, in Harrogate, fears that as more and more filling stations cease to sell the fuel, thousands of motorists in Yorkshire could be left stranded.

It is not necessarily the end of the road for your prized classic car or rusty old family motor, however.

"If you currently use lead replacement petrol there are a number of alternatives available - but it is vital that you start planning for the changes now," says Nigel.

So what can you do if you can't find anywhere to fill up?

The AA gives this advice:

Buy a lead replacement additive which is specific to your make and model of car (you can check what additive is needed by looking in your car's handbook or asking the manufacturer or local dealer). These come in bottles or syringe-like applicators and are poured into the vehicle's tank, along with unleaded petrol.

This means you can fill up with unleaded and then simply add the correct amount of additive.

The additive should be available from motor accessory shops and filling stations - and because unleaded petrol is cheaper than LRP, you could actually save on your petrol bills.

It is inconvenient, however, as the dose has to be fairly accurate, the AA says.

Simply switch to unleaded. It could take thousands of miles for the coating which lubricates the valves to wear off.

So if you have an old car that you're simply running into the ground, it may not be worth worrying about the effect of using unleaded petrol. Eventually, this will damage the engine: but if you're going to scrap the car within a year or two, does that matter?

Have your engine modified to run on unleaded. This is quite feasible for most cars, and many classic cars which people intend to keep have already had this work done.

The cost could be as little as £50 to £100 if all you need is to have the timing reset, or several hundred pounds if you need to have new valves and hardened valve seats fitted. It is worth contacting the manufacturer first, however, the AA says - because you just might be in for a pleasant surprise. Some manufacturers began introducing cars that could run on unleaded petrol before 1993 - so just because your car is more than ten years old, doesn't necessarily mean it will need adapting.

Updated: 09:17 Thursday, April 03, 2003