I bought a new full thermostat (with housing and such), and I'm gonna replace the coolant by the same time.

By any chance, doaes anybody know the size of the sealing washers I'll need to replace..?

As well, where could I find some sealant..?

washers?? i thought they were on o-rings, they should have come with the new stat...

you shouldn't use sealant, use blue hylomar on stuff that is associated with the cooling system, try halfords it's only a couple of quid for a tube

washers?? i thought they were on o-rings, they should have come with the new stat...

I'm talking about the ones under the engine, when you purge the water from the circuit.

you shouldn't use sealant, use blue hylomar on stuff that is associated with the cooling system, try halfords it's only a couple of quid for a tube

Thanks, I'll have a look!

there is no washer under the engine which needs renewing.

its only a metric 14 sized cap

there is no washer under the engine which needs renewing.

its only a metric 14 sized cap

In the Haynes manual, page 1A.17, in the paragraph "Cooling system drainig" at step 6, it says :

Clean the drain plug threads and fit the new sealing washers.