You’re damned if you do and damned if you don’t, unless you’re using Evans Coolant. That’s a pretty drastic statement, but let me back it up.
When an engine is running hot with antifreeze in its cooling system, the operator can get into a situation where there are no good options to avoid overheating and potential engine damage. If the antifreeze temperature rises to its boiling (failure) point, there can often be no good way to recover the system equilibrium. Let’s say you’re driving a vintage or muscle car in town and the temperature gets out of hand. I think any motorhead knows the stress of that moment and the need to make the right decision soon.
If you pull over and turn the engine off, the pump stops moving coolant and the fluid in the engine will boil away; this is often referred to as afterboil. It can raise the pressure in the system above the rating of the cap because the steam cannot be released as quickly as it is building. This is a threat to hoses, hose connections, and pump seals in motorcycles. If the head has gotten especially hot on the exhaust valve side, it can warp, ruining the head gasket seal and making it necessary to remove the head to resurface it.
If you continue to run the engine to keep the pump going, you are continuing to create heat. The low RPM of idling may make less heat than revving it, but the pump speed is low enough that cooling is likewise reduced. Getting out onto an open road is not always an option.
We saw this situation at the first two rounds of the American Flat Track motorcycle series this spring. At the Daytona TT, one of the bikes on the podium had a big blue antifreeze puddle under it from afterboil; the air temperature was in the 50’s, the track speeds were high, and there was no dirt or mud in the radiator so the conditions were not those normally associated with overheating. At the next race in Georgia, they stopped the race to clean up after a crash and a number of machines using antifreeze boiled over. The announcer was saying how they should be using Evans Coolant as the riders were going in circles trying to get their bikes to cool down. While I don’t want to name the teams that were overheating, I will say that the winner of both events, Jared Mees on the factory Indian FTR750, never had a problem. You will be surprised, I’m sure, that we are a proud sponsor of his racing effort! You can watch the Flat Track racing live on Fanschoice.tv or on NBC Sports starting in July. We’ll see you at the races!