Fiesta MK4 diesel - Thermostat - pullgees

Can I change the thermostat without draining the coolant.? The coolant is fairly new so don't want to have to renew it again. and I know that by draining off either by removing the bottom hose or rad plug, usually results in the coolant running all over the place picking up dirt.
Could I sipon some coolant out of the expansion tank first so that I get level down below the thermostat?

Fiesta MK4 diesel - Thermostat - TeeCee

Could I sipon some coolant out of the expansion tank first so that I get level down below the thermostat?

You'd empty the expansion tank, but not the cooling system. It does what it says on the tin, provides for expansion of the coolant.

If it were me, I'd clamp the hoses to the expansion tank and heater to preserve their contents, remove the top hose, losing the minimum necessary that way, change the thermostat and then top up afterwards.

Actually I wouldn't. I'd just drain the lot and refill. Life's too short to worry about a few quid's worth of antifreeze.

Fiesta MK4 diesel - Thermostat - pullgees

Thanks for the tip, it was easier than I thought.
I loosened off the drain plug on the rad just enough to get a decent flow but not enough to cascade all over place, so minimizing getting dirt in the coolant.
The after market themostat had a very feeble O ring, the original fed round the outer edge of the stat but the new one did not have a channel on the inside to do that. when I tried it and put the cover back on it din't squash up to create a seal. Anyway I put the original back on. No leaks so far.

 

Ask Honest John

Value my car