Hi can anyone help, this is my first post.
I have a Rover 1.8 2004 which currently has over heating problems. I have changed the thermostat or shall I say replced it as the garage that I purchased the car from, had in their wisdom decided to remove it without telling me.
I have also changed the pressure cap and coolant temperature sensor and have totally flushed and reverse flushed the system, yet it still overheats. There is no water in the oil and no petrol vapours in the expansion tank. I am convinced that it is down to an air lock but will find out when my vacuum filling tool arrives on tuesday, so i can eliminate this issue.
Does anyone know what the whitish yellow plastic thingy is connected to the bottom radiator hose?
It has what appears to be a second thermostat inside.
I have currently bypassed this to see if it makes any difference, but by doing this will it cause any harm?
Please advise as i am at my wits end. all contributions will be greatly appreciated.

kelvyn123, September 2009

hi kelvyn,i noticed this question on here from you in september 2009,i have recently got the same problem and as its october 2010 i was wandering if you might have a solution by now?i know that the head gasket going is a common fault on these rovers so it might be that but thats a big job.mine seems to have an airlock and it overheats really easily and boils over,its got a bit more serious today as i ran it boiling for too long,when i pulled up it was smoking and the engine is tapping and now its noisy at the bottom end aswell.if you did find a repair or remedy yourself could you please let me know,its a lovely car apart from this frigin problem.other faults recently happening that might be involved are wont start then rock the car and turns over and starts but didnt even turn over 30 seconds before,no warning lights showing but temp gauge goes up and down 3 or 4 times in a minute when hot,overheats/boils then expansion tank is empty but no leak????please help.

rob/erol, October 2010