Topping Up Radiator (sealed system)

[P1800Ray]

I was going to top up my radiator via the expansion tank bottle but it states “Do not open, see instruction book” on the cap. The same message is on the cap of the radiator itself.

Should I ignore the message on the expansion tank ?

[arcturus]

Top up via bottle when cool. Don't open bottle cap when hot!

[cassell]

Originally Posted by P1800Ray

I was going to top up my radiator via the expansion tank bottle but it states “Do not open, see instruction book” on the cap. The same message is on the cap of the radiator itself.

Should I ignore the message on the expansion tank ?

Both caps can be opened, just be careful if the engine is hot with the coolant under pressure. Ideally just top up when cool via the expension bottle to the 'low' mark, coolant will expand to the 'top' mark when the car is next driven.

The 'do not open' warning stickers are to prevent scalding by pressurised coolant erupting!

[Ron Kwas]

Ray;

As Arcturus suggest, top up Expansion Tank when everything is at ambient temp (Condition 1)...but watch for scalding hot Coolant if this must be done hot!). Otherwise, only open Rad when ET is empty (Condition 5, which means Coolant level in Rad is unknown, and Auto-Burping is ineffective because siphon has been lost).

See also: https://www.sw-em.com/cooling_system...ons_grapic.jpg

Cheers

[simonvolvo]

Originally Posted by P1800Ray

I was going to top up my radiator via the expansion tank bottle but it states “Do not open, see instruction book” on the cap. The same message is on the cap of the radiator itself.

Should I ignore the message on the expansion tank ?

You seem to have an odd sticker on the cap your expansion tank bottle. Mine says: FILL UP COOLING SYSTEM HERE - SEE INSTRUCTION BOOK

And, as they say, if all else fails read the instruction book: