CITROEN H VAN FUEL TANK CLEANING
Classic Vehicles regularly have issues with contamination of the Fuel, usually by rusting of the Fuel tank itself. This contamination makes it's way into the Carburettor blocking jets and causing poor running, loss of power, poor Starting, etc. See bottom of page for Diesel Tank issues/Cleaning.
The H van Fuel tank is very well made but will rust over time, especially if left standing. The flaking rust seems to be able to make it past the filters, don't ask me how, but it does. We had one van with 2 inline filters and the Carburettor still had contamination.
Removing the tank is not hard and cleaning it is not hard, but does take a little while. We would recommend the tank is thoroughly cleaned as part of your restoration to avoid reliability issues. See this website of how to clean a fuel tank, one of the best articles we have seen :
Try to minimise issues by keeping the Fuel tank as full as possible and never letting it run low as then is the greatest risk of all the rubbish at the bottom of the tank being sucked up into the Carburettor.
If you let the tank run low, fill up and soon after have engine running issues, you can be pretty sure the carb will be full of bits.
Don't just Clean the Carb, replace the Petrol Filter with a really quality item, then clean the Tank.
Jeff Winterman has had a special run of brand new Fuel tanks made, see : http://www.hyspares.net/ then go to "Items on promotion".
Diesel Tank Issues
For Diesel Engines the tanks still rust giving particle contamination as above but you also have the problem with 'Diesel Bug' turning the Fuel into a Tar like substance if it stands unused for a few months. If you have bought a Diesel van that has stood for a while, the tank will almost certainly have a 'Diesel Bug' problem. See here for more info : http://www.siriusmarine.co.uk/diesel-additives/1/OneShot-Diesel-Bug-Biocide.html
One van we had in the workshop had stood a long time and all the fuel lines, Pump and Injectors contained what we at first thought was Bitumen. We tried petrol to disolve it, White Spirit, Brake Cleaner, Brake fluid, etc. None were effective. We bought a supposed Bug Killer/Tar remover which definitely softened the Tar like substance but it took a long time to work and we ended up mechanically removing the stuff, which took a very long time.
Next time we will try the above Tank cleaning process as that sounds like it will shift it? If you try it, be cautious as the reaction of the Caustic Soda on the 'Tar' might produce gassing?
We think the problem is only really an issue in recent years because of the lowering of Sulphur which had previously kept the Bug away (Sulphur is a pretty obnoxious substance). The addition of a percentage of Fatty-Acid Methyl Ester (FAME), more widely known as biodiesel, by some Refineries/Distributors is also a contributory factor as FAME can contain a higher percentage of Water on which the Diesel Bug thrives.
While Diesel Bug has been common in the Marine world for about 10 years, few we spoke to in the automotive industry were aware of it, primarily because the Diesel in most cars gets used fairly quickly so the Bug has no time to develop. However a H van they can spend a lot of time 'resting' so look out for it.
Be especially wary about buying a Diesel van that is a none runner and be prepared for a big bill on cleaning the Tank, renewing the fuel lines and overhauling the Pump/Injectors.
You may find some people dimiss what we say above about Diesel Bug, "nonsense", some said to us, "I have been driving Diesel cars for 50 years, never had a problem", etc but we happened to be overheard discussing it and a guy said, "I work for the council as a mechanic on the vehicles and it's a real problem for us". "Some lorries stand idle for long periods, like the Gritting Lorries. They stand all Summer and then won't start at the beginning of Winter because of 'tar' in the tank, blocked lines". "Started happening about 4 years ago and just got worse". "We tried the marine Bug Killer, but didn't work". "In Spring 2014 we drained down the tanks and put in some Parafin. At the start of Winter 2014 we inspected the tanks, with no visable issues at all, just added Diesel which mixes ok with the Parafin". "This Winter was the first Winter every Lorry was ready to grit and we have not had any Ice!!!".
"Remember a few years ago when we got hit early on by a really hard Winter that suddenly caught us by surprise in October, was it 2012? Only one Gritting Lorry would start. Every other Lorry was in the workshop full of Tar. We worked 24 hour shifts for 8 days trying to get them clean.