Hi guys i think i am getting exhaust gas build up in my 96 GQ RD28 as it pushes coolant to the over flow bottle.
Coolant does not return to radiator.
I have put new thermostat in new water pump new clutch fan and new radiator it does not over heat at the moment sits about half way on temp gauge or just over half when i am doing about 110km with air con on
i was hoping for some advise on a additive to put in to it to hopefully last me to next years tax time so i can get it fixed properly.
There are a few head gasket and block crack products on the market like Chemiweld that claim to work for leaks but i can not find any info if they fix exhaust gas leaks.

Has anyone had a similar problem or know if there is a product i can try for a temp fix
thanks in advance for any information that may help me
Cheers Geoff