What happens if you don't flush coolant?

Like the oil in your engine, coolant needs to be replaced periodically. If you do not replace the coolant, over time it will become acidic and cause problems in the cooling system. Corrosion and sludge can form and clog up passageways. Blocked coolant flow or deteriorated coolant can both lead to overheating and catastrophic engine damage. It is not always necessary to flush the coolant, but it does need to be replaced regularly.

Can I just drain and fill coolant?

Some mechanics insist that a coolant flush is more effective than simply draining and filling the cooling system. Others argue that a coolant flush is unnecessary. If your vehicle has a significant number of miles on it, or if you have neglected cooling system maintenance in the past, a coolant flush can help to remove harmful residue in a way that a drain and fill procedure cannot. Otherwise, draining and filling the coolant is sufficient. It should be noted that some manufacturers do not recommend flushing the coolant but rather drain and fill instead.

Can I do a coolant flush myself?

Adding engine coolant to top off the system when some fluid escapes can be done by most motorists, as long as the specific type of coolant is used. Some vehicle owners might be able to drain and refill the system or even perform a fluid flush using the engine’s water pump. Of course, a true fluid flush with a dedicated flush machine can only be done if you actually have the equipment. But in any case, extreme care must be taken when servicing the cooling system beyond a simple top-off. If air becomes trapped in the lines, overheating can occur. Many vehicles are prone to this problem. Therefore, it is best to have a trained mechanic perform the procedure.