Most people think that oil is the lifeblood of any van engine, but coolant is an equally-important fluid that is absolutely essential. In case you didn’t know, coolant is the fluid that is either red or green in colour and has a “sweet” smell (ethylene glycol), although I wouldn’t be tempted to drink any of it as it is highly toxic and can potentially kill you!
Sometimes known as antifreeze, the purpose of coolant is to literally cool your van engine down as it operates at extremely high temperatures. Coolant runs through your entire engine from the top where the cylinder head is located down to the bottom where the “block” is.
Coolant is pumped around the engine by something known as a “water pump” and goes through a heat exchanger (the radiator) where it is cooled as it passes through.
All engines have a fan that is attached to the radiator so when the ambient and engine temperature under the bonnet rises to a certain level, the fan operates and cools everything down.
Some people might not know this, but coolant even passes through a heat exchanger in the cabin of your van (the heater matrix). This is how you can get nice warm air coming through your air vents on a cold day.
The importance of changing your engine’s coolant regularly
As you can see, coolant really is an essential part of any van engine and performs a number of functions. But as with oil, coolant needs to be replaced on a regular basis in order to ensure that it is performing as expected.
The photograph shown above depicts an engine with fresh coolant. This fluid doesn’t need to be changed as often as your engine oil, but if it is left for several years its cooling properties start to breakdown and sludge begins to form inside of the engine.
In those extreme cases, van service centres have to flush out this sludge as it can block the internal coolant passageways inside of the engine, in various radiator hoses and in the radiator and heater matrix too.
Luckily it’s not too difficult to flush out coolant sludge as all you need to do is remove the two radiator hoses (one of which is for draining the coolant), and stick a hosepipe with pressurised fresh water into the other to unblock the system.
How to check your engine’s cooling system
It would be better not to have to do this in the first place, as it is a fairly involved and time-consuming job – and an expensive one if you get a mechanic to do it for you! Here are some simple tips to help you check the condition of your engine’s cooling system:
Expansion tank – assuming the engine is cold, remove the cap from the coolant expansion tank and check if there is any sludge underneath the cap or inside of it. Top up the tank if necessary;
Cooling fan – start the engine from cold, set the interior fan to “cold” and let it idle for at least five minutes. The temperature in the engine should rise (according to your dashboard), and the radiator fan should eventually kick in.
John from Western Van Centre recommends getting the coolant in your van’s engine replaced at least every two to three years.