At the helm
by Dave Helms
Ferriaris in Heat
It is the end of May, and as I sit down to write this column on understanding and maintaining your Ferrari’s cooling system I have a lovely evening with a fire in the fireplace, and snow falling like a February blizzard outside! But… It will be HOT soon,… really!
OK…The first step to maintaining your cooling system is to understand it. When one thinks of a cooling system, you normally think of the radiator, hoses, and water pump. On a Ferrari, that is just the beginning. Remember the last time you had the oil change done, and you had to pay for what seemed to be an endless amount of oil? Depending on which model you have, the engine holds between 8 and 24 quarts of oil. Compare this to a standard domestic car that holds around 5 quarts. At any given time, even at high RPM’s there is less than 1 quart of oil that is being used for engine lubrication, the remainder is utilized for cooling purposes.
Most of the later models have what is called a dry sump lubrication system. The name describes the purpose, in that there is a pump in the engine that keeps the engine sump empty. All of the extra oil is kept in the oil coolers and the oil tank and is used for engine cooling only. The oil that is pumped into the engine is routed so that once it has lubricated the rotating parts, the run off splashes parts that need cooling. Valve springs and pistons for example would fail in a very short time without the cooling effects of run off oil. All of this leads to the question, have you checked the fins of your oil cooler lately? Take a moment and look in your owner’s handbook and locate where the oil cooler for your model is located, and look for any debris that might be plugging the passage of air through it. Many a 308 has come into the shop with a plastic grocery bag, or candy wrappers covering the entire cooler.
This leads us to the components we all think of when a cooling system is discussed. The radiator cooling fins are an often-overlooked component. If you look through the grill of say a 308-328, you will see what appears to be the radiator cooling fins. It is actually the air conditioning condenser that you see out front, and all of those bent over fins have a large effect on the ability of air to pass through the condenser to actually reach the radiator. Taking the time to gently straighten those fins with a plastic serving knife will help a tremendous amount. Incredible what damage can be done at 75MPH+ when a fair sized bug hits those fins! With that done, we get to the single most common source of overheating I see on the 308-328 series. Take a very bright flashlight and look down in between the A/C condenser and the radiator while a helper shoots a mild stream of water from a garden hose through the condenser from the front. Years of weed seeds, hay, and untold other residue will then show its self. It is not uncommon to find over 1/3 of the radiator covered with some type of swarf that will completely block any airflow through it. In many cases it is necessary to remove the radiator and condenser assembly to clean it properly. With all of this restored to proper working order, top up the cooling system reservoir to the brim, and run the engine for 3-4 minutes, then shut it off, and crack open the bleeder screw on the top of the radiator, and let coolant run out until there is no longer any signs of air bubbles. Do make sure that you have the heater valve on hot when you purge the air out so you address the whole system. Repeat the bleed out again with the engine running.
A great number of the later Ferrari models have cooling system bleeder screws to remove the air trapped in the system from when a slightly loose hose contracts while the engine is cooling down. The 308-328 series, Mondial’s, TR’s and 348’s all have a number of bleeders that must be addressed from time to time. Later models such as the 355’s and 360’s have the coolant reservoir mounted high enough that hoses constantly bleed the system without the need for manual bleeder screws. Early models used the time tested, low-tech concept of gravity to eliminate any trapped air.
Taking all this into consideration, if you have flushed the coolant system, checked the belts and hoses, cleaned the radiator, and properly topped the coolant (and bled the air out on models that need it) , you should now be set for a full summer of cool driving….have fun in the sun !!
-- dave helms --