mercanlandy
Active Member
P38 2.5 (BMW straight 6)
Have had a few overheating issues since having to replace a split hose at rear of engine. Refilled system with new coolant and water. All seems good but temp gauge sits a full mark higher on temp guage, more near center of normal. Before problem with split hose it would always sit just at top of blue cold mark. After runs of 20 miles it starts boiling over. I was suspecting head gasket damage but I have just had mobile mechanic round to do tests for head gasket failing, all tests showed no issues with head gasket. No bubbles coming into test rig and chemicals did not change colour which would have indicated exhaust gases in header tank. The mehanic says problem is either an air lock or water pump not pumping water around or a blocked radiator. I did put a tin of head gasket repair fluid into the water system following the hose splitting issue just in case any head gasket damage may of occured. I now think this may have blocked the radiator causing the engine to over pressure and boil up. Or an air lock. I fitted a new thermostat last week but problem is still the same. What is the proceedure for purging air properly out of water system. Last try before I replace water pump and radiator.
All help, getting desperate now
Have had a few overheating issues since having to replace a split hose at rear of engine. Refilled system with new coolant and water. All seems good but temp gauge sits a full mark higher on temp guage, more near center of normal. Before problem with split hose it would always sit just at top of blue cold mark. After runs of 20 miles it starts boiling over. I was suspecting head gasket damage but I have just had mobile mechanic round to do tests for head gasket failing, all tests showed no issues with head gasket. No bubbles coming into test rig and chemicals did not change colour which would have indicated exhaust gases in header tank. The mehanic says problem is either an air lock or water pump not pumping water around or a blocked radiator. I did put a tin of head gasket repair fluid into the water system following the hose splitting issue just in case any head gasket damage may of occured. I now think this may have blocked the radiator causing the engine to over pressure and boil up. Or an air lock. I fitted a new thermostat last week but problem is still the same. What is the proceedure for purging air properly out of water system. Last try before I replace water pump and radiator.
All help, getting desperate now