Freeze Plug Replacement: Causes, Symptoms, What to Consider, and Other FAQs

During manufacturing, your engine undergoes a casting process to complete its mold and shape. It involves creating core holes to remove the casting sand. It isn’t safe to leave these holes open, most of which are in the cooling system, so freeze plugs were created to secure them.

Why Are Freeze Plugs Important?

Aside from sealing the sand-casting core holes, freeze plugs keep the coolant in the engine.

Also called core plugs or Welch plugs, freeze plugs are small and cylindrical, but they can be larger in high-performance engines. They’re usually made of metal, rubber, and other materials.

Freeze Plugs in the Past

Before coolant and antifreeze, water was used to cool down the engine, which was problematic during the winter months. Water can freeze and cause the engine’s passages to expand. Freeze plugs released the pressure from the expanding ice, preventing cracks from forming in the cooling system.

What Causes Freeze Plug Problems?

Most freeze plugs are made of metal or galvanized steel, making them vulnerable to rust and corrosion. If your cooling system is poorly maintained, moisture and acidic contamination can damage your freeze plugs and other parts of your cooling system.

Acidic Contamination

If you don’t flush and replace your coolant according to your manufacturer’s recommendation, your antifreeze will become acidic. Any acidic substance isn’t good for the integrity of the metal.

The acid will damage the freeze plugs until they’re beyond repair. You’ll have no choice but to replace the plugs once it happens.

Signs of a Faulty Freeze Plug

The most obvious sign of freeze plug issues is a coolant leak. But if there are no obvious leaks under your ride, how would you know your freeze plugs are bad?

Here are other signs you can watch for that can indicate that it’s time to let a mechanic inspect your freeze plugs:

Strong Heated Coolant Smell

If you can’t see visible leaks, look for a sweet odor, which is how burning coolant smells because it contains ethylene glycol. Never ignore any unusual odor while you’re on the road. It can indicate that something is wrong with your engine.

White Exhaust Smoke

White smoke can be an indication that coolant is going through the inside of your engine. Burning coolant can flow through hot components inside your engine, producing a white smoke that smells sweet. Take your ride to an auto repair shop once you notice unusual smoke coming from anywhere in your vehicle.

White smoke can be an indication that coolant is going through the inside of your engine.

–Anthony Harlin, ASE Certified Master Automobile Technician

Overheating

The engine frequently overheats when there isn’t enough coolant circulating in its system, which can damage a lot of engine components in the long run.

Take note that you can’t conclude that these problems are caused by bad freeze plugs. After all, other failing cooling system parts can exhibit coolant leak symptoms. For an accurate diagnosis, have a mechanic inspect your cooling system.

Can I Drive with Bad Freeze Plugs?

Yes, you can, but experts don’t recommend it. Your coolant will leak out. Once it does, your engine will have low coolant. There’ll also be air in the cooling system. This can lead to frequent engine overheating, resulting in engine damage in the long run.

Replacing Freeze Plugs

Replacing freeze plugs isn’t that hard, but they can be difficult to reach. Mechanics usually remove the intake manifold, alternator, or exhaust manifold to get to these plugs. In some cases, you’ll also have to remove your transmission. There are some freeze plugs located on the rear of the engine—between the engine and the transmission.

The parts’ location varies depending on the vehicle. If you don’t have the tools and the technical know-how to replace bad freeze plugs, it’s best to pay a professional to do it for you.

How Much Does it Cost to Replace Freeze Plugs?

You can get an aftermarket freeze plug for around $20 to $50. The price depends on its brand, quantity, and intended vehicle.

If your engine uses multiple plugs, you’ll have to consider that in your expenses. If the replacement requires the mechanic to lift the engine or transmission, you might shell out around $900 or more for the whole process. on top of taxes and other related repairs.

What to Consider When Buying Freeze Plugs

To find the best freeze plugs for your ride, consider these factors when shopping for replacements:

Material

When buying freeze plugs, check what type of plugs your engine uses. Common freeze plug materials on the market include brass, steel, and rubber.

Size

Freeze plug sizes vary depending on the vehicle’s make and model, so make sure you know which size fits your engine.

Quantity

Car cooling systems can have multiple plugs. If yours have several, consider buying complete freeze plug kits. Otherwise, you can buy new freeze plugs individually.

Brand

If you’re going the aftermarket route, make sure to buy your freeze plug from a trusted brand. If you don’t have a go-to brand yet, you can check out product reviews online to have an idea about a product’s quality.

Get a Replacement Freeze Plug That Fits Your Car

A faulty freeze plug could cause coolant leaks, resulting in engine overheating and failure. Repairs can get pricey, with some going over $1,000. To prevent paying a hefty bill, get a replacement freeze plug with CarParts.com.

Here at CarParts.com, we value and prioritize our customers. That’s why we have everything sorted out for you. Using your laptop or mobile device, you can browse our wide selection of freeze plugs and find the perfect replacements. Use our vehicle selector to narrow down the options to compatible plugs, then adjust the filters to your preferred brand and quantity.

We ship from strategically located warehouses across the country, meaning you’ll get your replacement piece days after ordering it. Plus, all our freeze plugs are available at unbeatable prices to give you the best value for your money.

Don’t let your coolant run out and damage your engine before replacing the freeze plug. Check out our selection of quality freeze plugs at CarParts.com.