hi guys i have a gs300 sport mk1 but about every month a have to top up my overflow bottle not buy much but have to top up.is there any comon thing that normally goes.have checked but at the moment cannot find any leaks.temp gauge always reads normal.any help would be most greatfull.

[quote name='kevinsgs300' date='18 June 2010 - 08:45 PM' timestamp='1276890343' post='723869']
hi guys i have a gs300 sport mk1 but about every month a have to top up my overflow bottle not buy much but have to top up.is there any comon thing that normally goes.have checked but at the moment cannot find any leaks.temp gauge always reads normal.any help would be most greatfull.
[/quote]

nothing I can think of other than a leak. The radiator is most like to go on the front where It is not very visible due to the air con radiator in front of it. If you undo the two top brackets on the main radiator, you can tilt it back slightly to see in between. Green discolouration is a key indicator that there is some seapage from the rad. Failing that, if there really are no signs of leakage anywhere externally, I would get a pressure test done to check the head gasket.