5 things you need to know about motorhome engines

Author: Malcolm Street   Date Posted: 25 June 2019


Motorhome engine types explained

Generally speaking, most motorhomes in New Zealand and Australia have turbodiesel engines. There are a few exceptions to this. Small campervans, the likes of those based on Toyota HiAces for example, have 2.8L or 3.5L (in the new model) petrol engines. At the other end of the scale, USA-built motorhomes often have something like a 6.8L petrol engine. Not exactly great for fuel economy in the latter case…

Otherwise, apart from larger A class rigs, most motorhomes will have a turbodiesel engine sized somewhere between 2.2L (four-cylinder) and 3.0L (six-cylinder). This is at least for the European-built cab chassis such as Mercedes-Benz, Fiat Ducato, Volkswagen Crafter and Ford Transit. The Japanese tend to have larger engines, such as the Isuzu NPR with a 5.2L (four-cylinder) turbodiesel.


1. Why diesel?

In case you are wondering about the predominance of turbodiesel engines, they are better suited to the light commercial truck world for both their fuel economy and power/torque attributes and, since most motorhomes are built on light commercial cab chassis, there is not much choice. That’s not a bad thing because for the same reasons diesel engines are well suited to motorhomes as well. That, of course, may well change in the future given the tightening of diesel emissions in Europe.


2. Demystifying engine brands

Badge names in the commercial truck world are a little confusing, especially because some manufacturers have technology-sharing arrangements. There are Peugeot Boxers that look like Fiat Ducatos and Mercedes-Benz Sprinters that have looked like Volkswagen Crafters.

But, even though the bodies might look the same, sometimes the engine and transmissions are different.

On the motive power front, Fiat uses a 2.3L engine with three different power ratings. Thus there is a Multjet 130, a Multijet 150 and a Multijet 180 for the same sized engine. Even more confusingly, although we live in a mostly metric world, just about all Euro and Japanese truck manufacturers still use horsepower ratings. Consequently, the Multijet 130 is a actually a 96kW engine, the 150 is a 109kW engine and the 180 delivers a maximum of 132kW.

Mercedes-Benz is almost as bad. For instance what does the 414 CDI badge mean on its Sprinters? Translated, CDI is Controlled Diesel Injection, the first 4 is a weight figure, meaning a GVM of 4490kg and the 14 is 140hp (105kW). 519 CDI means a GVM of 5000kg and a 190hp (140kW) engine.

After all that, Iveco Daily’s 70C17 doesn’t require much translation at all, does it? A 7000kg GVM with a 170hp (125kW) turbodiesel. Iveco does the same trick as Fiat here, its 3L, six-cylinder engine has either a 125kW maximum power rating or if a second turbocharger is added, then it gets up rated to 205hp (150kW).


3. What about the power?

I’ll use Fiat as the example here because there are some differences between Europe, New Zealand and Australia. In the latter, the usual choice of Fiat engine is the most powerful — the Multijet 180hp/132kW. This is mostly because travelling distances are long and motorhomes tend to be heavier.

Motorhomes that come out of Europe go the other way, using the lower-powered Multijet 130/96kW for the opposite reasons, shorter distances and lighter vehicles.

New Zealand finds itself in the middle with a mixture of locally-built motorhomes and imports from both Australia and Europe. Although I’d be going for the most powerful engine I could get, the weight factor is important too and 300kg to 400kg for the same length motorhome can make a considerable difference in the engine choice.


4. Torque matters

Maximum power figures aren’t the only things of interest in a truck engine. Torque is also important and is defined as a force that rotates things.

Diesel engines generally have better torque ratings than petrol engines which is why they are better suited to heavy loads, something that includes not only motorhomes but also when towing caravans. That’s the reason most of the world, except curiously North America, has used them for most commercial vehicles.


5. Maintaining your engine

Like most cars, servicing periods for diesel engines have been extended greatly over the last 10 years or so. However this does not mean ignoring service requirements, particularly with items like oil changes and diesel particle filters.

Emission requirements have forced many truck manufacturers into producing smaller engines with greater power outputs. Consequently there is a much greater reliance on turbochargers and technology. Logbook servicing should be given the attention it needs, as should daily/weekly checks on items like oil and coolant levels.


For more information about various engine types available across the KEA and Roller Team range of motorhomes and campervans, contact the friendly team at RV Super Centres in Auckland or Christchurch.
Ph: 0800 52 00 55

RV engines

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