Honest John: can I get my Mercedes serviced by a local garage without invalidating the warranty?

Our 'agony uncle' advises on what to do if you want to save money and have a scheduled service carried out outside of the dealer network

A woman mechanic fixes a car while it's raised on a ramp
Can you really get cheaper car servicing while maintaining franchised dealer standards? Credit: FRED DUFOUR/AFP

If your car has developed a fault, or for consumer advice, turn to Honest John by emailing [email protected]

Maintaining momentum

My two-year-old Mercedes GLA 200 Sport auto has done 23,600 miles since purchased in 2018. When I booked its second annual service at the selling dealer, I was told it would cost £510.70. I understand that the service includes a change of engine oil and brake fluid (but not gearbox oil) and, if I wanted to wait, it would take two and a half hours. I then visited the local garage where my Volvo S40 has been serviced for seven years. They quoted £240. Having added a three-year extended warranty (for £1,300) as part of the original purchase, I was concerned that if I used my local garage, the Mercedes main dealer would find some excuse not to honour the warranty. My local garage assures me that MB cannot do that provided the service work is done by an MoT-registered garage, which they are, and properly itemised. The only snag is that Mercedes service history is now recorded online and sometimes the local garage has difficulty accessing this. However, they say that manual records will still provide the necessary proof. What is the best way to proceed? PG

It is nothing to do with being an MoT station. The EC ruling is that everything must be to manufacturer standards, so every minute detail of the service needs to be recorded on the invoice: all procedures used; all parts and fluids used. But I would not have an expensive car like this serviced independently and run the risk of voiding the warranty until the latter had expired. I had a big service on a small Fiat in March and, with MoT and brake fluid change, even that was £360. Always relate the cost of the service to the cost of the car (and the cost of a new engine if it needs one).

Forester grump

I purchased a new Subaru Forester hybrid at the end of November 2019. I’ve had the AA out three times because of a flat battery that controls the electronics. I use the car mainly for local trips. The reason the dealer gave for the flat battery is that I don’t drive it enough. I’ve had other cars and that’s never been a problem. I asked the dealer for a tougher battery. He just says I should drive it more, so now I’m wasting my time and petrol just driving it around with its headlights on (this was suggested by the dealer service department to make the alternator work harder). Any suggestions you may have would be much appreciated. JH

That is a standard problem with a self-charging hybrid that is not a PHEV (Plug-in Hybrid Electric Vehicle). If the car is used for a succession of short runs, the internal combustion engine does not operate sufficiently to recharge the 12-volt systems battery. The answer is to occasionally put the 12v battery onto the correct charger for the AGM battery, such as a CTEK CT5, maybe once a week. Or simply to drive the car further with the headlights on, which forces the engine to start and the alternator to recharge the 12v battery.

Narrow margins

I have owned a Fiat Doblo for five years, converted to a Wheelchair Accessible Vehicle (WAV) to accommodate my wife’s wheelchair. I would like to change it because it is 10 years old, but a later Doblo is too big to fit comfortably into my garage. I can’t find a new WAV narrower than 83 inches including mirrors; my Doblo is 78 inches. If I am forced to stay with my present Doblo, does it need a replacement cam belt together with water pump at his age, even though it has done only 31,000 miles? If so, is it a job best left to a Fiat dealer or can I entrust it to a local garage? LO

Space cruiser: should you replace a 10-year-old Fiat Doblo with a newer one?

The need to replace the timing belt depends on the engine. If it has a belt, then on most engines (VW Group EA211 excepted), toothed belt, tensioner, water pump and auxiliaries belt should all be replaced. Fiat dealers charge about £400, which is reasonable. But if it has the Fiat 1.3 Multijet diesel engine, then that is chain-cam and all you need to do is keep the oil clean. If seeking a new replacement, a Ford Transit Courier is 77.8 inches wide, so a tiny bit narrower than your Doblo. Ford offers a five-door Courier Combi with a 1.5 diesel engine or its 1.0 EcoBoost petrol engine. McElmeel converts them in various configurations:  www.mobility-services.com.

Up fill struggle

Perhaps there's a perfectly good reason why the car is filled with water... Credit: Lesley Bennett/SWNS

My VW Up continues to fill with water. I checked all the drain holes in the doors with various tools and they seem to be clear. I managed to access the drains at either side of the plenum area between the dashboard and engine compartment. There was some debris, which I removed. I can pour water through the drains and see it coming out under the car. The bottom part of the hatchback has no accessible drain holes, so I cannot drain it other than by opening it wide, but this, at least, has not got worse. The sloshing noises on any corner or movement of the car have not gone away, but there is now water in the off-side footwells, front and back; so bad that the over-mats have gone mouldy underneath. I recently had a lift from a relative with a 2016 VW Up and he had exactly the same problem. He says a VW dealer charged him £60 to access the plenum chamber and clear it. I am worried that I cannot keep this car dry and it will go rotten. I have checked on Google and Up owners report a depressing amount of similar problems, with quotes up to £1,500 to rectify. I have booked it in with the selling VW dealer who is charging £85 to investigate and report. Is there anything else I could do? GE

I found two more possibilities: A report of significant rainwater leak into the driver's footwell of a 2015 VW Up after being left standing for 10 days. The supplying VW dealer traced the leak to a faulty seal where wiring passes through the bulkhead separating the engine and passenger compartments. The owner was charged £1,000 to rectify. Also a badly refitted, or cracked, pollen filter cover, which I experienced myself in a Seat León many years ago, when the pollen filter was replaced as part of a service. But it was so difficult and fiddly to put back properly that the mechanic had given up. It the same in many other VW Group cars due to the conversion of a left-hand-drive design to RHD.

Hot and bothered

Hot stuff: the Hyundai i800's large glass area make air-conditioning essential

I bought a 68,000-mile, 2009 Hyundai i800 for £7,793. It has a full service history and has just had a new clutch, dual mass flywheel and slave cylinder. However, the air-con is not working at all. My local garage said there will be a leak in the system but would want to run a test before quoting, which would incur a cost. They suggested going back to the selling dealer as it has a warranty for three months with a limit of £500 per claim. If I had known the air-con was broken I wouldn't have bought it, because the i800 is a mobile greenhouse in the summer and I always leave the air-con on to keep the air dry in the winter. I like the car and just want it fixed. The local garage is willing to do this. The dealer is two hours away. What should I do? DC

No insured warranty can cover a pre-existing fault. That is the liability of the dealer. I would get quotes from an air-con specialist and submit them to the supplying dealer. I suspect that the condenser has failed. www.airconditioningforcars.co.uk is very helpful. To find someone more local, use Google.

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