Vacuum filling the coolant into an engine is a trick adopted by many car manufacturers.
It allows coolant to be drawn into the system with no air locks so the engine doesn't require bleeding.
This saves time, effort and spilt coolant.
Instead of pushing coolant in under pressure or pouring the coolant in and using gravity to fill the system from
the bottom upwards, vacuum filling pulls all of the air from the coolant system leaving little to no air to create
an air lock. The vacuum in the system pulls the coolant in and evenly distributes around the entire system.
Bleeding the air locks out of the petrol 450 and Roadster is an easy one.
The petrol 451 is a bit more of a pain but but can be done with simple tools.
The same can't be said for the diesel engine in the 450 and 451. It is possible but it's a bit of a mess about.
If you buy a vacuum filling unit and the air compressor required to power it, you are looking in excess of £150. This
is far too expensive for something that you may not regularly use. So I decided to make my own. Even if you have to
buy everything, it's not going to be much more than £50. However, many people will have the most expensive part.