Annual Cooling System Flush
by Glenn Merrell, TriStagReg@aol.com
Editor’s Note: Although this article was originally written for the Stag with a specific reference to a heater core supply line connection on the left head, the general flushing procedure itself should apply to all Triumphs.
When preparing to perform the annual flush of the cooling system, obtain a good quality flushing detergent. Make sure it states that it is not harmful to aluminum, and ones with corrosion inhibitors seem to work the best. Prestone has a two part flush powder – one half is detergent for the flush, the second part is corrosion/rust inhibitor used in the rinse flush. First disconnect the heater core from the flushing by removing the feed and return hoses. Reverse flush it later by using a cut off garden hose attached to the heater return port (normally connected to a pipe that runs to the water pump cover) and connect a length of hose to the supply side of the heater core (normally connected to the left hand head) and route it into a drain. Reconnect the two engine side heater hoses using a suitable length of copper tubing, or if using a power flush connection, this is a good place to connect the tap. This bypass of the heater core will keep you from depositing the crud from the engine and cooling system right into your heater core. (You would only notice this when the weather turns colder and you were wondering why the heater does not work, as you panic to think that the cooling system has gone too.) Drain the cooling system and radiator by removing the lower hose on the radiator, disposing of the coolant properly. Remove the thermostat and reinstall the “water elbow” or “gooseneck”. Follow the directions for flushing the system, being careful not to boilover or overheat the heads. If using a power flush system using the garden hose, make sure that the water is on for the whole engine flush cycle. Never pour cold water into a hot engine, as you will surely warp the cylinder heads and possibly crack the block. While the cooling system is flushing,