Why are you replacing the thermostat? Did you take it out and test it and find it defective? If you do replace it make sure you replace it with a thermostat that does have the little bleed hole in it and not a standard US type with no bleed hole. To bleed the system all you have to do is remove the radiator reservoir cap and refill the system. If you have the correct type thermostat in there the air will automatically flow to the top of the system and bleed to the reservoir. Leave the cap off for a few minutes to allow air to escape, then run the engine till it warms up enough to open the thermostat and you start getting warm coolant back in the reservoir. All the air should be out by then. The small bleed hole in the thermostat allows air to escape without running the engine. Leaving the cap off the reservoir just eliminates any pressure resistance making it easier for the trapped air to escape. Running the engine afterwards with the cap off just moves any trapped pockets of air out and through to the reservoir. Once the motor is warmed up and you see no more bubbles of air you can replace the reservoir cap. It should be a green cap, not the old grey one. Good luck......


Mike