2002 V70 75kmiles. When changing thermostat, why.....

Post by **ssforcey** » 03 May 2008, 04:59

When changing the thermostat out why do you have to drain the coolant? I know probably a stupid question but wondering why and what happens if you don't?

Thanks so much,
Sharon

Post by **MadeInJapan** » 03 May 2008, 06:37

There are ways around doing a total drain (for instance, draining the coolant reservoir, clamping the major hoses, etc.) but you will need to drain some. If you don't, you will have a pretty large coolant spill from the thermostat housing which will make a mess. Right under the housing are belts, some sensors, etc. You just really don't want to get them wet with the coolant if you can avoid it. If it has been 2 years since the coolant was replaced, when you change your thermostat is an excellent time to go ahead and do a flush and put new in.