coolant

[peter Whitwell]

help please
whats the correct quantity of coolant please
conflicting info I've two hand books, one says 5 pints the other says 7 pints
should expansion  vessel be full at all times or only when engines is warm?
thanks in advance
Peter

[Hendred]

My Silk (MKii) takes just less than 4 litres to fill so that would be 7 pints.  The header tank is only full when the engine is hot. The water expands a surprising amount when it is hot.  If filled when cold the excess runs out the overflow as it heats up.

[peter Whitwell]

Thanks for your help -unsure if the expansion vessel really needs radiator cap?

or can i devise a new cap arrangement -but still have an overflow?

Unsure if there is any real pressure within the vessel

[Hendred]

The system is not pressurised.  I believe the cap is from a BSA oil tank.  The tank just vents to atmosphere through the vent pipe.  Water often drips from the vent pipe until it finds the correct level.  There is a lot of expansion when the engine is hot.  As there is no pressure in the system the vent pipe connection doesn't need to be very strong.

[Hendred]

Which part has broken off?  The whole neck and cap or just the small vent connection on the neck.

[Stenton]

May I suggest that, instead of the usual water/anti-freeze mixture, Evans Waterless Coolant - the Powersports version -  is a better choice?
This is from their website:
                                      Evans Waterless Powersports engine coolant, available in a half-gallon bottle, is designed for motorcycles, ATVs, UTVs and snowmobiles. It has been used by race teams around the world for years to keep their engines safe, no matter what the conditions. They don’t pull over to let their engines cool down, and neither should you.
Powersports coolant is ready to use—no water required. It contains no silicates or phosphates and requires no Supplemental Coolant Additive (SCA).
Boiling Point: Above 375°  Antifreeze Properties: Protects below -40°F
Benefits: Eliminates system corrosion, improves combustion, maximizes HP, prevents boil-over and freeze-burst, safe for pump seals and bearings.
Life Span: Protects for life of the engine.

There is more information on their website.