Challenger Coolant Pressurization Issue


I recently noticed a small coolant leak on Orange Krush. It appeared to be coming from the thermostat housing, so I replaced the thermostat gasket. This solved the small leak, but coolant began to push out of the coolant over flow reservoir. I started by replacing the reservoir cap, but after that didn't solve the issue I had to look at bigger problems. Typically when the coolant system becomes pressurized it indicates the combustion process is causing it. This means head gasket failure or worse, a cracked head. I ran several tests such as a block test and leak down, and both were negative. However, nearly everyone I talked to had me convinced it was a hair line crack in the head gasket somwhere so I proceeded to tear the engine down. The head gaskets were analyzed and found to be fine, as well as the heads themselves.


After re-assembly I still had the same problem. While checking the car over, I noticed the lower radiator hose was collapsing under RPM. I checked the radiator and cooling system for any restrictions and did not find any. I replaced the lower radiator hose, and inserted a steel spring in it to insure the issue was solved. This did infact solve the problem.


The below videos show the trouble shooting steps performed, disassembly and reassembly of the top end of the motor, as well as a time lapse of just the re-assembly I did for fun. If you find you have coolant pressurization issues, check that lower radiator hose before doing anything else.





If you found this article helpful make a donation to support Speedy's Garage.