Engine, HVAC

Stuck engine block coolant plugs? Here’s a $1 trick to break them loose.

I got a few of those 3/8″ square male coolant drain plugs in my block, and I tried using one of those

crappy universal 12-point sockets crappy universal 12-point sockets

to extract it. I looked up buying a set of

square female sockets square female sockets

, but I’m not going to spend $50 on that.

So I tried to figure out a cheap work around. Here’s what I figured out. It’s only going to cost you $1 at your local hardware store.

Step one: Put a 3/4″ hex socket on the plug. The hex should face out.


Step Two: Buy a threaded coupler. ($1 expense)


Step three: Place the coupler in your breaker bar.


Step four: Mate the coupler with the hex stuck to your engine.


Works like a charm. It can’t hurt to spray them with WD or PB Blaster before torquing them, but that’s up to you.



Update May 18, 2018:

While you have the coolant block plugs out, go to McMaster Carr and buy some 90 deg valves for both sides of your engine.

This will allow you to flip a valve open if you ever need to drain your coolant from the block in the future, instead of dealing with the awful mess of draining the fluid with a simple threaded plug.  Getting coolant on your skin is not good for your liver and organs, so minimizing the cascading waterfall of coolant resulting from a coolant plug removal is paramount.  These spiffy valves allow you to affix a one-foot section of heater hose to the end of the valve, so you can carefully and cleanly drain the block into a container without any mess.


No warranty. You are responsible for your vehicle. For novelty use only. Not responsible for anything or anyone. Not responsible for damage to your vehicle, you, or anyone or anything.

Copyright 2000-2018 Nick Pisca 0001D LLC