Cooling System

The 4.6L’s cooling system isn’t too bad but it can be drastically improved with a few modifications. One of the most common modifications is changing the thermostat for something cooler. The common replacement a 180 degree t-stat. One thing I would like to comment on is that the thermostat has no bearing on the engine performance whatsoever. It only determines at which temperature coolant starts to circulate through the system. After that, the performance that is already in your engine will determine your operating temperature. Also, revving the engine will NOT make your engine warm up quicker. It was once done on carbureted cars to keep the plugs nice and clean but today it is not needed. Here is a quote from Corral regarding the subject,

“Guido in Da Cobra) "If you're cruising on the highway w/a 160 degree thermo, your coolant is gonna be a steady 160 degrees due to all the air flow."

The thermostat opening temperature & airflow are two sides of the same coin. One is to insure that the engine comes up to an efficient operating temperature & the other insures that the operating temperature is maintained. However, if what you are saying is true, then no engine would ever overheat because every automotive thermostat is designed to function at well under even the most basic unpressureized boiling temperature (212 degrees F).

Your basic automotive IC engine can run efficiently between 180 & 220 degrees. Colder than that means that the pistons & rings will not expand effectively leading to increased contaminants in the oil, premature ring wear, scuffing of the cylinder walls & increased emission levels. And, of course, running too hot will lead to a breakdown of the lubricant &, eventually, engine seizure due to insufficient piston to wall &/or bearing clearances.”

One of the better modifications to the cooling system is an aluminum radiator. Not only do these help cool the engine more but they reduce ambient temperatures as well as lightening up the car. Fluidine and Steeda make what I consider the best. Steeda’s is a rebadged C&R, or so I’m told. The Steeda one will fit boost pipes without a problem, however, the Fluidine one will not.

In 1999, they changed the water pump’s impeller to reduce cavitations at higher RPMs. This means water is less likely to boil or vaporize at higher RPMs. The 1999 and 2000 is a direct bolt-on with the older models but in mid 2001, they changed the water pump pulley style. These can be found directly from Ford. Under-drive pulleys also help reduce cavitations.

Electric water pumps are also available for our cars that provide even better cooling and help reduce some drag, which equates into extra horsepower. These should not be used without a coolant gauge however, as if it fails, you are pretty much screwed. The gauge will help you see that it is slowly failing. The Meziere is the most common electric water pump out there.