Why is oil temperature so crucial to good engine health?
Why do so many tuner and race cars run oil coolers? Because oil temperature is one of the most important aspects to keeping your engine running. Literally.
Extreme oil temperatures drastically shortens the life of the bearings which keep your engine spinning, for a variety of reasons. Firstly, the temperature of oil affects its viscosity (AKA, the oil’s slipperiness) which is why oil has numbers like 0w-30, 5w-40, and the like.
These numbers refer to how viscous the oil is when cold and what the upper temperature range is. When oil gets hotter than its peak operating temperature it starts to thin out.
This means hot oil isn’t offering protection to engine bearings as the viscosity drops off, heating bearings up and leading to all sorts of damage occurring. Expensive damage that will take a lot of work to fix and leave you with no way to drive to the shops.
If oil temperature is important then logic dictates engines that cop an absolute flogging will need to have very good ways to keep their oil cool. Many factory engines will feature some form of basic cooling system but when you are pushing a tuned-up engine much harder than regular street driving the only way to keep your oil from getting too hot is to add an external oil cooler… although this doesn’t need to actually be mounted outside the car.
Having an oil cooler tapped into your factory oil system adds cooling performance in two important ways: one, by using air flow over the heat exchanger to drop the temperature of the oil passing through it; and by increasing the engine’s oil volume.
Keeping your engine oil cool is important when you’re beating your car like it owes you money, getting your oil up to temperature is also important. If your oil is too cold it won’t be at its most slippery, leaving your engine in danger of wearing prematurely.
In the same way a thermostat works on a car’s cooling system, it is a switch that opens a passage to the oil cooler once a pre-set temperature has been reached – if the temperature drops below that number the thermostat clicks the passage shut and removes the cooler from the circuit, until it is once again needed.
These thermostats are simple to hook-up, though it is important to use good quality fittings and hoses, and to mount the cooler, lines and thermostat securely.