What Freeze Plugs Do In An Engine (And Signs They Might Need To Be Replaced)

In the event you’ve inspected your vehicle’s engine block closely, you have likely noticed just a few strategically placed metallic discs that look somewhat misplaced. The discs are typically cup-shaped plugs, although some automakers and aftermarket examples use different styles. They’re used to seal openings into the water jacket of aluminum and cast-iron engine blocks.

This proximity to the engine’s coolant system will be credited with the freeze plugs’ commonest name, and is a number one explanation for their failure. Maintaining the engine coolant in your automotive needs to be on a brief list of automotive maintenance items it’s best to check on. Along with maintaining the correct level, a test to confirm the correct antifreeze concentration can be essential. If the coolant freezes contained in the engine block, there is a likelihood a number of freeze plugs could absorb the pressure of the expanding liquid to avoid wasting the engine block from cracking. Nonetheless, the system doesn’t at all times work as effectively as you would possibly hope.

Knowing that freeze plugs are used to stop engine coolant from leaking out, it’ll come as no surprise that one in all the primary signs of freeze plug failure is usually a fluid leak under your automotive. While coolant leaks can spring from quite a lot of sources — coolant hoses, radiator, heater core, water pump, etc. — it is important to trace them down and make the needed repairs before you are left stranded.

Metal freeze plugs can fail because of corrosion from inside or outside the engine block and from being dislodged by freezing engine coolant or other external aspects. To find out if a coolant leak is coming from a freeze plug, you’ll have to examine each freeze plug and the encompassing area, especially the realm below the plug. If a leak is not immediately apparent, locate the coolant leak on the bottom and look up, taking note of any components the coolant can have dripped on.

In fact, if freezing temperatures have pushed a freeze plug from its bore, coolant will run out like it has been poured straight from the bottle. The resulting coolant loss can result in engine overheating. As a proactive measure, especially should you fear the engine coolant has frozen, inspect freeze plugs to make sure they’re still fully seated of their bore.