Doubt about plastic valve on top of engine ( C270 CDI )

[paulinho]

As title mention, what´s the use of the black plastic valve on the top of the cam cover on a C270 cdi engine?
It´s the end of low pressure fuel lines.
When i had to change 1 fuel line i had a lot of problems in bleeding the system, and i wonder if it´s a bleeding point

Thanks

 

[BlackC55]

It is a point to measure the low fuel pressure.

 

[paulinho]

Thanks...
Whats the best way to prime fuel lines?
The last time i emptied 3 batteries to crank the engine

 

[BlackC55]

Fill the fuel filter with fuel and crank the engine over. It should start in about 15 seconds.

Thdere is no method to prime the fuel lines as such. It does it well on its own as long as the filter is full of fuel.

 

[paulinho]

your a great help in this forum and for that...