Alex Robbins is contributing editor at Telegraph Cars where, as well as responding to readers’ queries, he also contributes reviews of new and used cars, together with articles on buying and selling. 

His knowledge of the used car market informs his many buying guides relating to the best buys in particular sectors, with an emphasis on value for money.  Every week he will answer your questions on buying and selling, as well as solving your car problems, whether consumer or mechanical.

Do you have a motoring dilemma you’d like our expert to solve?  For consumer and used car advice, or car faults, email CarsAdvice@telegraph.co.uk and include your subscriber number. This week’s question… 

Dear Alex,

I recently bought a four-year-old Honda CR-V but I am keeping my existing VW Golf Estate, which is 12 years old with 145,000 miles; it will be useful for taking garden waste to the tip and for transporting logs for our woodburner. I am concerned that doing so few miles in the VW will clog the diesel particulate filter. Would it be worthwhile using a particulate filter additive to aid the car’s longevity?

– JB

Dear JB,

As with any of these fuel-additive cleaners, opinions vary as to whether diesel particulate filter (DPF) cleaners actually work or not. Some users say they get great results; others think they aren’t worth the cash.

Where they tend not to work so well is if you try using them with a car that already has a blocked DPF – while they might help to prevent carbon deposits from forming, they don’t tend to be strong enough to shift larger, more stubborn deposits already present.

Having said that, I’ve heard of several drivers who say they’ve experienced good results using these products as intended, which is to say, as a preventative measure. This involves pouring a bottle full down the fuel filler nozzle with every third or fourth tank of diesel. 

Trouble is, given each bottle costs about £10, this can soon start to get quite pricey – and of course, if the DPF never goes wrong, there’s no way to know for sure whether they’re actually doing their job, or whether it’s just serendipity. 

Your car has obviously done quite a few motorway miles, so I’d imagine the DPF is in good shape as it stands, and given you intend to use a DPF cleaner on a preventative basis, I’d say it shouldn’t do any harm, and might even help. 

But I also think that getting the car to regenerate its DPF properly every so often will do more to stop your DPF getting blocked up, and probably cost less in the long run. 

To achieve this, you’ll need to get the exhaust up to a high temperature, with high gas flow; the best way to achieve this is a decent (say, half-hour) run at motorway speeds, with the revs kept somewhere between 2,000 and 4,000rpm. 

Granted, that won’t be part of your usual driving habits now the Golf has been relegated to tip run duty – but it might be worth finding time for a quick spurt along the nearest dual carriageway every few weeks.