BMW E36 Forum

any ideas 1998 328i convertible heater stopped working topped up coolant over heats when driven hard fine when driving easy changed thermostat nothing still over heats checked water pump all ok head gasget?

Did you check the system for any blockages?
Sounds like the the coolant isn't getting round the system fast enough as its only happening when driven hard! Use a good cooling system flush, then run plenty of water through it and refill with adequate water/coolant mix for your climate.
Also its not very well known but you should really use bottled water in your cooling system. Bottled water has been filtered and has no chlorine added into it!
Also, don't cheap out on the coolant flush, go to your local motor factors and ask them to suggest a good one for a blocked system.