Could there be serious internal engine corrosion issues with a petrol engine - like that fitted to this car - that is rarely used ?

No problems at all providing the oil is fresh and uncontaminated. All parts will be coated and the oil film will be OK for years.

2 examples.

I bought a Mondeo engine out of a burn out caused by a dash fire (faulty phone install). The fire brigade had liberally soaked the engine as they extinguished the fire and the plug galleries were full of orangy coloured water. It had been at the yard for ages and they were glad to see the back of it. I took the sump and head off and all was fine.

In 2008 I bought a brand new crate 2 litre Focus Zetec. The engine was built in 2004 (when the last Mk1 Focus was sold) and had been stored (along with many others) in a warehouse since. All the oily bits still had a coating of oil on them and no corrosion but its must be said it had probably only run on the bench at the engine plant (if they do that sort of thing).

BMW will have programmed the engine to run occationally even if the batteries are full so nothing to worry about at all.

A serious question - one I hope our engine builders / rebuilders might reply on, in particular.

Could there be serious internal engine corrosion issues with a petrol engine - like that fitted to this car - that is rarely used ?

We all know that exhaust back-box corrosion can be a major problem when the water from combustion condenses - which typically happens when the entire exhaust doesn't get hot enough on very short trips. Could this happen with a hybrid where the engine might only run for a couple of minutes, so is pretty cold a lot of the time ?

Its not something Id be worried about to be honest, good quality oil and fuel look after engine internals pretty well and BMW like most Germam brands will have a stailess steel exhaust system. Best practice is likley to run the engine periodicaly and fully heat everything up.but that will happen in normal use anyway I suspect.with the limited battery range. Internal corrosion is mainly caused by acid thats a byproduct of combustion.

Edited by Stanb Sevento on 07/07/2017 at 11:50

Could there be serious internal engine corrosion issues with a petrol engine - like that fitted to this car - that is rarely used ?

Apparently, the car's brain has a routine which turns the engine over periodically (without starting it, effectively spinning it on the starter) to circulate the oil around the engine and keep the high-stress surfaces like cam lobes & followers, cylinder bores etc lubricated ready for service, to minimize start-up wear and corrosion.

Just back from a two week holiday in the Yorkshire Dales. Handily, the place we were staying had an outdoor 13A socket so I was able to charge the car and do a fair bit of driving (including the 15-mile round trip to the nearest town) on electric-only.

Filling up when I got back home showed we'd used bang on 5 gallons for 381.3 miles = 76mpg. The electricity was 'free' but as mentioned in previous posts, it's fair to assume that the car uses about 60p worth of electricity per day. Over 14 days that's £8.40, which is equivalent to 1.5 gallons of unleaded. So the 'combined' fuel cost was 58mpg.

That's better than I used to get with either of my previous Volvo V60 diesel manuals. Considering the BMW weighs more and is more powerful, I'm very pleased with it.

Otherwise the car continues to be very comfy, practical and fun to drive.

One interesting and unexpected feature that was discovered while on holiday was the car's part-time 4WD mode. I was in electric-only mode, reversing into a parking space on wet grass. It was quite a steep uphill reverse and the rear wheels (driven by the electric motor) span a little due to lack of traction. To my surprise, the petrol engine automatically started up to give me all-wheel drive, so I could complete the reverse easily. Smart!

One particular question if you see this, Craig, put into my mind by the current thread on 'creep' - does the automatic 'creep' like a normal auto? I would hope so!

It does, irrespective of whether it's on electric-only, petrol-only, or both. Considering that there is no physical connection between the petrol engine & trans and the electric motor apart from some wiring (unlike many other plug-in hybrids, which have the electric motor sandwiched between the petrol engine and trans), the powertrain's integration is seamless.

The 'combined' economy (i.e. petrol plus electricity) works out at 50.2mpg

And that is exactly why I will not be buying any brand of hybrid any time soon.

A 2 series petrol can be had for £21800 from Carfile wheras the hybrid will set you back just over £30000.

Assuming that the 218i would match the Superbs 45 mpg overall I would have to do over 600,000 miles at todays petrol price to recoup the extra purchase price.

A work colleague found that out over 4 years ago when he got a new Auris hybrid as his company car. It would only just beat the mpg I was getting from the Leon but he had to drive like a dead vicar to achieve that figure. He also found the car very tiring over a long distance beacuse of the hateful CVT continously revving the engine when you breathed on the throttle.

It makes most sense as a company car (because of the low BIK tax)

But he said exactly the same as your comment, compared to his previous Focus diesel he was saving a fortune.

At the weekend he preferred using his wifes C3.

Craig, I'd be interested to know how many miles you can go between petrol fill-ups. I believe the fuel tank is smaller on the 225xe to accommodate the battery, but maybe that's compensated for by the extra mpg.

A PHEV would make sense for me next time: up to now they've been too expensive, but there are signs that the gap is narrowing between petrol and PHEV versions of a model. But I do like the 400+ mile range that both our (petrol) Audis can do. As you'll remember, the diesel Volvo V60 would do over 700 with its 67-litre tank.

Yes, the petrol tank is just over 8 gallons. On a typical business trip of say 350 to 400 miles in a day, mostly motorway (where the petrol engine is running all the time and the electric motor contributes little), I usually set cruise control at 75mph, and will typically get a genuine 42 to 45mpg at the pump.

And that is the problem with older hybrids. Our much larger Skoda Superb 1.4 TSi 150 PS covers a trip of 430 in the day 4 times a year and its pretty much loaded. Setting cruise at 73 mph it averages a genuine 53 to 55 mpg depending on the weather and traffic. We can easilyget 700 miles from a tank before we get nervous.

It seems that the nnewer hybrids are much better but why pay a fortune for a "green" car that does less mpg than a conventional one with a good engine.

50mpg overall is a respectable but far from outstanding figure.

In pure financial terms it is not worth paying the extra cost of the vehicle.

The outcome is unsurprising:

• carrying extra weight of batteries, motor, control systems makes it less economical and slower
• saving a little through grid charging which is almost tax free compared to petrol or diesel
• paying a chunk more for outright purchase or (I suspect) lease

Not a decision I would take - but it's a free world and diversity is to be encouragged.

Well, after three years and 25,000 miles, it's going back to BMW this week as the contract hire is up.

Lots of interesting mpg figures in this thread but not many £ figures. Can you please tell us how much the 3yr 25K mile contract has cost for the actual car ownership/rentalship?