How do you change a core plug?

Core plugs is fitted in the round holes along the engine block. They keep the antifreeze inside, and I suppose they're meant to pop out if the antifreeze should freeze (normally below -34 degrees celsius).

Changing them is quite fiddly at least when the engine is in the car. The biggest problem is finding room for your hands and tools.

To remove a core plug take a punch and a hammer, and knock on one side of the coreplug, until it turns in the hole. Then grab hold of the other side with a pair of pliers. Twist and pull to get it out. Be extremly careful not to knock the plug into the engine block. You might not get it back out, and it might get stuck in such away that you won't get a new core plug in. You might want to bore a hole in the plug, so you can grab the plug with pliers or pry it loose with a screwdriver through the hole.

Estimated time used to remove a core plug the first time you do it is 1,5 hours, in addition to the time need to make room to work on the plug and removing antifreeze.

To install a new core plug, get a socket that fits exactly inside the plug (which might be hard to find) and use an extension and a hammer, to drive it back in the hole. Take extreme care to make sure the plug is driven straight into the engine block. If it's not straight a leak will occur.

Estimated time for installing a core plug for the first time is one hour, in addition to remounting parts and refilling antifreeze.

If you're installing an engine heater, read the heaters installation instructions. Different heaters will not fit in all core plug holes. You may need to remove a specific plug.

Oh. And if you go ahead and to this, remember: You might render your engine useless or in need of major repairs, and it's not my responsibility.

And a last note: I did this on a volvo 245. They have very large engine rooms with loads of workspace, and yet I had trouble finding enough space for my tools (especially the socket and room to swing the hammer hard enough). I will think twice before doing it again. The only pleasant part of the job is the price of the core plugs, at only 4 dollars.

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