A week after it announced a big recall, Ford Motor says that it has pinpointed the cause of overheating. It says a simple software update will fix the fire risk in the 2013 Fusion sedans and Escape crossovers with a 1.6-liter EcoBoost engine.
The problem, it turns out, was a combination of two issues, says Raj Nair, Ford's vice president of global product development. "We had a sequence of events that caused the cooling system software to restrict coolant flow," he says. Most of the time, he says that would not be big a deal.
But if the car has another cooling system issue that could result in low pressure, such as a loose filler cap or a pinhole-sized puncture in a hose, the coolant could boil. If the coolant boils over, the engine goes into extreme overheating. Coolant leaks out and comes in contact with the hot exhaust system, catching on fire. Ford said it has seen 12 fires in Escapes and one in a Fusion.
The coolant needs of various parts of an engine vary with conditions, such as cold weather or during warm up. Ford engineers found that in certain conditions, water was being directed into the radiator to be cooled, but a closed valve briefly -- such as for 15 seconds -- prevented the coolant from flowing back into the engine.
That, too, normally is not a problem -- the engine easily can handle the very short time without coolant return. But again, if another issue has resulted in low pressure, the coolant never makes it back.
The software flash will ensure that water is not directed into the radiator unless the electronically controlled return valve is ready to send it back.
Nair says the repair will take about a half day. Mechanics will check customers' cooling systems to make sure they have not overheated already.
This is the third recall of the Escape with this engine for separate fire risks since its introduction last summer -- the first for a defective fuel line and the second for a coolant plug on the engine. The redesigned Fusion just went on sale this fall.
Nair says Ford has full faith in the 1.6-liter EcoBoost engine, which has been used in Europe since 2010. More than 80,000 have been made in Europe, where there have been no recalls, but where the engine has a different cooling system.