What would cause a freeze plug to come out?

Asked By: Inaki Postgens | Last Updated: 29th February, 2020
Category: automotive auto parts
4.5/5 (1,396 Views . 12 Votes)
As with many things on a car, there is an "official reason" and a "REAL" reason for freeze plugs. When water freezes, it expands. If water freezes inside your engine block, it can expand and crack the block, destroying the motor. Freeze plugs (or expansion plugs) will "pop out" and supposedly prevent this.

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Considering this, what causes a freeze plug to leak?

In some cases, as the water freezes and expands in your block, the freeze plugs will push out relieving the pressure of the freezing water and partially draining your cooling system. However, freeze plugs can also start to leak over time simply due to the heating and cooling cycles of driving your car.

Beside above, how much does a freeze plug cost to replace? The freeze plugs are made of very thin metal. And if they rust, they leak. Ray: To replace the freeze plugs, you have to remove the engine. That's why the bill is $1,000.

Furthermore, how do you get a freeze plug out of a block?

Place the flat end of the screwdriver inside the freeze plug and hit with a hammer until the “eyelids” are elevated and sticking out. Be careful so you are not pushing the freeze plug into the engine, then you have some problems. Hit it at the side of the freeze plug. Use your lock pliers to remove the freeze plug.

Can you drive with a bad freeze plug?

Yes, the engine will run but will have a coolant leak. A freeze plug is a thin metal cap pressed into and engine blocks coolant passage. The engine will still run as long as the coolant level is topped up. Since a freeze plug is the lowest point of the engine, the coolant would likely leak out very quickly.

28 Related Question Answers Found

Can you JB Weld a freeze plug?

JB weld will hold and seal a freeze plug a long time and if the surfaces were properly prepared it might outlast the engine.

Will Stop Leak fix leaking freeze plug?

Freeze plugs prevent water from freezing inside an engine, and also help hold cylinders in place inside the car. A freeze plug that needs repair will be leaking coolant, and will need to either be resealed or replaced, depending on how bad the damage is.

How do you fix a freeze plug?

FREEZE PLUG REPLACEMENT. To remove a freeze plug, first hammer it into the block with a big screwdriver or a large punch. It won't go far into a modern engine: there isn't much room behind the plug. When it "pops through" you can easily pry it back out of the hole sideways with a pair of pliers or a screwdriver.

How hard is it to replace freeze plugs?

Installing freeze plugs is not hard, but there are some complications that arise. Some of the freeze plugs are easy to reach, but there are some that are impossible to reach with the engine in the vehicle. Once the water melts, the coolant will start to leak from the freeze plug. Corrosion failure is a bit different.

Can a bad freeze plug cause overheating?


A faulty freeze plug in the engine block can also be responsible for allowing coolant to leak from the system. Loose or faulty gaskets on the engine can enable coolant leaks to develop, causing an overheating of the car's engine. A bad radiator cap can also cause coolant fluid to leak out on a continual basis.

Where is the freeze plug located?

Depending on your ride, the freeze plug could be located on the side, back or underneath the engine block.

What is an expansion plug?

DIYers often refer to a core plug as a freeze plug or expansion plug, thinking that they're designed to pop out and protect the engine if the coolant/water ever freezes.

Where are the freeze plugs on a Ford 302?

1987 302 f150 freeze plugs. they are three on each side of the block down lown around the motor mounts, front and back of heads, and one on the back of the camshaft inside the bellhousing.

What are signs of a blown head gasket?


How To Tell if a Head Gasket Is Blown:
  • Coolant leaking externally from below the exhaust manifold.
  • White smoke from the exhaust pipe.
  • Bubbles in the radiator or coolant overflow tank.
  • Overheating engine.
  • White milky oil.
  • Fouled spark plugs.
  • Low cooling system integrity.

Can freeze plugs be reused?

No - do not re-use it. The sides of a freeze plug are slightly tapered to become a press fit in the opening. Once the plug has been used, the sides have been bent in and it will not fit as tightly as it should. They are so cheap that it's not worth the brain power to even think about it.

Do freeze plugs leak oil?

As said above your freeze plugs will not be leaking oil. Get a can of engine degreaser when the engine has cooled down, cover electrical connections and your alternator, spray degreaser/cleaner, let soak, rinse with hose. Spray with compressed air or allow to dry for 12-24 hours.

Why is my car overheating but it has coolant in it?

A common cause of car overheating is a low-cost thermostat stuck closed, restricting coolant flow. A blown head gasket can be the cause or the result of car overheating issues. Coolant can leak out, air gets sucked in, and the engine temperature needle wraps around to full hot. Plugged heater core.

What happens when a car freezes?

If the block freezes hard enough to pop out a freeze plug it's likely toast. Starting a car with frozen coolant will usually burn off the belt trying to turn a frozen water pump. Engine heat will not thaw radiator hoses or the radiator itself so the engine will over heat and possibly blow off the upper radiator hose.

How do you install a block heater freeze plug?


To install:
  1. To install the freeze plug, coat the new plug with silicone sealer and clean the block mating surface free of rust and corrosion.
  2. To install the block heater, coat the O-ring with engine oil and clean the block mating surface free of rust and corrosion.
  3. Connect the negative battery cable.

Do freeze plugs need sealant?

And you can't realistically "test" your freeze plug installs. You put them in, put the engine in, fill it with coolant and cross your fingers. 99% of the time you probably don't need any sealant.

What is a frost plug heater?

A frost plug heater is an electric heater that heats the engine of a vehicle to give quicker starts and protects your engine from damage that can occur during cold weather starts.