This article was written in reply to a new owner who had bought a 1988 B544 Hymer with an big underslung LPG tank, and wanted info. Most tanks are 40m 50 or 60L, so if you have a smaller tank - adjust the estimates accordingly - and remember - they are just estimates.
If the van is LHD then is likely an import, and the tank could have been fitted any time since. They were never a factory option - always fitted by dealers or gas companies - here or in Germany (usually).
Now what you have to understand about gas is that the equipment doesn't last forever, and at the very least should be checked over every 10 years or so. That is not to say there will be any danger - lots of people love to shout doom and gloom whenever the word gas is mentioned - I am not one of them. I know of plenty of original gas tank systems that are over 30 years old and still going strong. If you have reasonable common sense you can inspect the system visually and assess it yourself. If it fills with gas at the pump, and then after standing still on level ground with no wind, you can't detect the slightest whiff of gas from anywhere, and the appliances appear to work fine, then you have taken reasonable precautions and are most of the way there. But the general common sense attitude is that you should have any gas system checked over properly at least every 10 years. if you have children, it's more or less a duty!
The most important component is the regulator. Regs do have a use by date - and should be replaced every 10 years. Old regs can and do fail, and it is a regular question on this technical group. An LPG tank reg is the same as a bottle reg, but is usually bulkhead mounted, or mounted out of sight near the tank. Remember that old german vans pre 95 almost always have 50mb gas systems - not the 30/37mb that is the modern standard. Don't let any gas guy tell you otherwise.
if you do feel it prudent to have it checked over, then this group does have a recommended gas guy - Charlie Lister at Autogas 2000 Ltd up in Yorkshire. He will fit a new reg and check things over, and is a mine of info on all things gas. There are other firms dotted around the country, but Charlie knows Hymers and motorhomes in general and has been an invaluable source of advice over the years - so worth the trip.
About the gauge - the glass ones fitted on the tank are hard to read, but generally reliable. Study it carefully so that you understand it - you really have to read the dial to get to know what is empty and full position. There are usually accessory LED level gauges available nowadays, and these are convenient.
Your tank looks quite big - around 60L. The normal 11kg German bottles that fit the gas locker are 11kg, and there is 2kg in a litre. So 2 bottles is around 44L. The germans fitted them for 2 main reasons - 1. Long periods between refills, minimum hassle, max time on site or off grid. 2. Crossing European borders. There are several different bottle systems in different countries, which makes gas bottles an expensive inconvenience for long euro road trips, especially in winter.
So LPG tanks are the system of choice for long termers and road trippers. If you are planning multi country Euro trips, then you have a good asset. A new LPG tank system is around £1000 these days. I swear by mine - had it for 8 years now, been all over Europe and it has paid for itself twice over. All you need is a set of LPG pump adaptors and you are good for any country - and LPG is much cheaper than bottle gas. There are a few idiosyncrasies - ie no LPG in Morocco, and different tax rates in Italy, but I've always managed. LPG availability is also a factor. There has been much discussion in recent years about LPG slowly disappearing from UK forecourts, and this is true, mainly because of the electric car boom, but LPG as a fuel will be around for decades yet, and the only inconvenience I have found is that you have to plan your fill ups - there are non forecourt sources in most big towns and cities, and there are apps that tell you where they are. On the continent there is no problem.
Consumption wise, in summer, fridge and cooking, a 60L tank will last you for months - at least 3 or 4. In winter, when you have the heating on, then a tank will last you at least a full month using the heating for 12 hours a day. I have a 40L tank and in cold weather with the heating on 24/7 - ie non stop, I get 1 to 2 weeks. In summer it's every few months. It is heating that uses gas - fridge and cooking are low consumption.
At the other end of the scale - if you had it checked over and a professional condemns it - corrosion perhaps - then you can have it removed and revert to gas bottles for not much money - the plumbing will still be there and the installer will remove the old tank and install new fittings in the gas locker. This would probably be the best option if you don't want to shell out for a new tank - ie if you only plan to stay in the UK and not use the van very often, and only in summer. But I only add this for info - it is highly likely that your system will check out OK - most do.
