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BMW and MINI Fuel System Rust and Corrosion, Lines and Tank, Gas and Diesel

February 21, 2017


* Frienemy – (Urban Dictionary):
Friend/Enemy – A “toxic” person who poses as a friend but subconsciously or consciously wishes you harm.

This is exactly what the gasoline or diesel fuel is to your BMW or MINI.  It’s the friend that makes all things work ….. and the enemy that can destroy your fuel system and even the engine itself.

Moisture in gasoline and diesel fuel has always been an issue due to contamination in storage and transport, as well as condensation within the storage vessel (such as the vehicle fuel tank).  Additionally, today’s gasoline, that commonly has ethanol added, tends to separate the water molecules from the fuel, rather than suspend the molecules within the fuel.

Why should we care about moisture (water) in our gasoline & diesel?

There are two basic issues that make water contaminated fuel a bad thing for our BMWs and MINIs.

1) Water contaminated fuel does not burn well in the engine’s combustion chambers.  This can cause minor misfires that may or may not be felt, very rough engine running – all the way to the engine refusing to run at all.

2) Water in the fuel system will promote corrosion and rust within the metal parts of the system (tank, lines, pump, injectors).  This corrosion can actually eat through a tank or fuel line, but also damages the pump and the fuel injectors, causing these expensive assemblies to need replacement.

By the time you notice the problem, it is often too late.”
The chemists at Liqui Moly recently performed a telling test.  An accelerated corrosion test was performed with a steel rod inserted into a solution of naptha (a safer and inert replacement for gasoline) with  just 10% water.  After just 24 hours the steel rod was rusted.  In the same test, with Liqui Moly fuel system additives, the steel rod shows not rust at all.

How do we prevent fuel system corrosion and rust damage?

1) Keeping the fuel tank fuller, rather than lower, will help to keep condensation in the tank to a minimum.  This is also much better for the longevity of the in-tank fuel pump.  Click HERE for an article on this subject.

2) Regular use of a moisture barrier product will help to keep the interior metal surfaces of the fuel system protected from the corrosion and rust formation.  The Liqui Moly Jectron fuel system cleaner and Super Diesel Additive not only clean the system of deposits and corrosion, but add the molecular protective coating to the fuel system’s metal surfaces.

Click image below for Liqui Moly Jectron fuel system cleaner:

 Click image below for Liqui-Moly Super Diesel Additive:


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