Carrying out the procedure on the open engine
If the vehicle comes to the workshop for a service, it is no longer necessary to observe clean room conditions, of course. Nevertheless, you should ensure a certain degree of cleanliness if you are going to work on the injection system. Regardless of whether it is a diesel or gasoline engine, there are a couple of important rules you should follow. The engine and injection system will thank you for it at the next service!
The MAHLE purity requirements
- Safety first: protective glasses and gloves are mandatory.
- Under the magnifying glass: before assembly, it is worth comparing the old and new filters with each other. Things that look similar on the outside may be different on the inside!
- No pressure: often there is residual pressure in the system, which should be eliminated, of course.
- All clean: a spotless environment prevents dirt from getting into the system.
- Clamp down: line filters (KL model) on the underbody are particularly prone to running dry when disconnecting the fuel line. Therefore, clamps should be used to prevent air from entering the system.
- A tight seal: open lines should be sealed with plugs. Additionally, the transport plugs on the filter should not be removed until immediately before it is connected.
- Everything must go: in the case of filter elements (KX model), the fuel must be drained from the housing.
- Good preparation is everything: prefilling the spin-on filter (KC model) with clean fuel avoids the tedious procedure of ventilating it later.
- In with the new: always use fresh gaskets.
- Lubricating well is half the job done: always coat the gasket with clean fuel before assembling it.
- Don’t get in a twist: rubber gaskets must not be twisted when fitted. Always check that they are positioned correctly, otherwise the new gasket will be squashed.
- No bending: fuel lines and pipes must also not be twisted or bent during assembly.
- Get the air out: the injection system must be ventilated cleanly—otherwise, it gets expensive. Injection pumps and air do not mix, and so the pumps must always be ventilated in accordance with the specifications. However, please do not fiddle with the starter until the engine starts—you can read about what can happen in that situation in our TM 02/2017.
- Completely sealed? A final performance and leakage test must always be carried out.
- So long! Naturally, old fuel must be disposed of in an environmentally sound manner.