what to do if you break your radiator drain plug / cock during a coolant change
07-12-2007, 03:36 PM
#1
2004 Winning Blue GT
Thread Starter
what to do if you break your radiator drain plug / **** during a coolant change
This is a set of instructions on how to get yourself out of a tight spot 
If you've read the threads on doing your own coolant change and flush, then you've likely seen the comments that suggest
that the drain plug / drain **** can be broken by overtorquing it. And now I can speak from personal experience- yes, it is possible, and it is a major PITA to fix. Better yet, I called Mazda and the service guy laughed and said he had never heard of anybody doing such a thing.
So you were most likely reinstalling the plug, and in the process of screwing it back in, you feel the plug give way. Lo and behold, you're holding the head in your hand and the screw is @$^&@ stuck inside the bottom of your radiator.
First off, take a deep breath. All is not lost, but you'll need to do a little bit of work. It is possible to remove the broken plug yourself and install a new one.
If you need to drive the car, it's still possible to do so (though you will be leaking coolant). Simply fill your radiator up with distilled water and drive away. Feel free to add a little antifreeze, but dont put in much because you'll need to drain everything again very soon. Make sure that you run the engine a bit and keep on adding water to make sure that you have too MUCH coolant. Driving for half an hour will easily leak a quart of coolant, and its better to have a messy engine than an exploding one. Check the coolant level before you go anywhere.
It's also possible to patch the bottom of the radiator, but I was unable to get the leak to stop completely. It's cheaper to just buy another couple of gallons of distilled water.
The next thing you need to do is look for a replacement drain plug. The drain plug is a standard Mazda radiator plug (10mm, 1.25 thread). I was unable to find to exact copy with the same part number, but don't worry- just look for a general Mazda plug. I found mine at a specialty auto hardware store. This shouldn't cost more than $5.
Now that you have a replacement, it's time to get the original plug out. Yes, it is possible! It took me two hours to do it, so make sure you're ready to lie under the car for a long time. Use a sharp knife for this step; I used the long blade on my trusty Leatherman. Stab the base of the screw with the tip of the knife. Try to get it in as far as possible and as off center as possible. If you use the center, you'll end up just gouging bits and pieces of the screw when you slip. Once the knife is in, attempt to twist the remains of the plug out (lefty loosy!). If the screw does not move initially, try digging deeper and apply pressure from an angle, not straight up. Do not stab in another location unless the current one really doesn't work, because the more cuts you make, the harder it is to get leverage.
Once the plug starts turning, DO NOT TAKE A BREAK. Resist that urge to breathe a sigh of relief and wipe your forehead. Instead, apply even more upwards pressure and start turning with gusto. Coolant may start coming out from the screw (if you refilled your radiator), and it will quickly get slippery. I took a break after the first quarter turn and failed to get any more movement for another 30 minutes.
The rest of this should be pretty obvious: remove the screw, take care to wear goggles and gloves if you expect coolant to come out, wait for everything to drain, and install the new plug.
Congratulations! You've spent less than $10+a few hours on this fix, and didn't end up buying a new radiator or something equally extreme.
I'll post pictures when I get a chance.
Hope this helps somebody. I spent 4 days running around like a chicken with its head cut off (including patching the car at 6am before going to a wedding, and better yet, doing the final fix an hour before leaving for a track day). I went through a number of temp solutions that all leaked, so skip that trouble and just use this straightforward process.
EDIT: Note that using a pocketknife isn't the best solution in the world. As others have pointed out in this thread, if you have a special drill set for getting broken screws out, use it and you'll skip the hardest part of this process.
If you've read the threads on doing your own coolant change and flush, then you've likely seen the comments that suggest
that the drain plug / drain **** can be broken by overtorquing it. And now I can speak from personal experience- yes, it is possible, and it is a major PITA to fix. Better yet, I called Mazda and the service guy laughed and said he had never heard of anybody doing such a thing.
So you were most likely reinstalling the plug, and in the process of screwing it back in, you feel the plug give way. Lo and behold, you're holding the head in your hand and the screw is @$^&@ stuck inside the bottom of your radiator.
First off, take a deep breath. All is not lost, but you'll need to do a little bit of work. It is possible to remove the broken plug yourself and install a new one.
If you need to drive the car, it's still possible to do so (though you will be leaking coolant). Simply fill your radiator up with distilled water and drive away. Feel free to add a little antifreeze, but dont put in much because you'll need to drain everything again very soon. Make sure that you run the engine a bit and keep on adding water to make sure that you have too MUCH coolant. Driving for half an hour will easily leak a quart of coolant, and its better to have a messy engine than an exploding one. Check the coolant level before you go anywhere.
It's also possible to patch the bottom of the radiator, but I was unable to get the leak to stop completely. It's cheaper to just buy another couple of gallons of distilled water.
The next thing you need to do is look for a replacement drain plug. The drain plug is a standard Mazda radiator plug (10mm, 1.25 thread). I was unable to find to exact copy with the same part number, but don't worry- just look for a general Mazda plug. I found mine at a specialty auto hardware store. This shouldn't cost more than $5.
Now that you have a replacement, it's time to get the original plug out. Yes, it is possible! It took me two hours to do it, so make sure you're ready to lie under the car for a long time. Use a sharp knife for this step; I used the long blade on my trusty Leatherman. Stab the base of the screw with the tip of the knife. Try to get it in as far as possible and as off center as possible. If you use the center, you'll end up just gouging bits and pieces of the screw when you slip. Once the knife is in, attempt to twist the remains of the plug out (lefty loosy!). If the screw does not move initially, try digging deeper and apply pressure from an angle, not straight up. Do not stab in another location unless the current one really doesn't work, because the more cuts you make, the harder it is to get leverage.
Once the plug starts turning, DO NOT TAKE A BREAK. Resist that urge to breathe a sigh of relief and wipe your forehead. Instead, apply even more upwards pressure and start turning with gusto. Coolant may start coming out from the screw (if you refilled your radiator), and it will quickly get slippery. I took a break after the first quarter turn and failed to get any more movement for another 30 minutes.
The rest of this should be pretty obvious: remove the screw, take care to wear goggles and gloves if you expect coolant to come out, wait for everything to drain, and install the new plug.
Congratulations! You've spent less than $10+a few hours on this fix, and didn't end up buying a new radiator or something equally extreme.
I'll post pictures when I get a chance.
Hope this helps somebody. I spent 4 days running around like a chicken with its head cut off (including patching the car at 6am before going to a wedding, and better yet, doing the final fix an hour before leaving for a track day). I went through a number of temp solutions that all leaked, so skip that trouble and just use this straightforward process.
EDIT: Note that using a pocketknife isn't the best solution in the world. As others have pointed out in this thread, if you have a special drill set for getting broken screws out, use it and you'll skip the hardest part of this process.
Last edited by kluge; 07-13-2007 at 07:06 PM.
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LadyJ (09-21-2021)
07-12-2007, 03:59 PM
#2
I zoom therefore I am.
I've always kept a set of these http://www.smarthome.com/89090.html?src=WG1003477 in my tool box just for reasons like this.
Glad to hear you were able to fix it yourself!
Glad to hear you were able to fix it yourself!
07-12-2007, 06:31 PM
#3
An RX ate my baby
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I've had that happen on another car- but it didn't take two hours to remove. I simply drilled a hole through the center of the plug, tapped a square milled EZ-out into it, and unscrewed it.
I also have a set of left-twist drill bits, those work pretty good too.
Trust me, you feel a lot more SOL when you break off an exhaust stud in a BMW head after having paid $100 for a gasket and you already tightened down the other bolts.
I also have a set of left-twist drill bits, those work pretty good too.
Trust me, you feel a lot more SOL when you break off an exhaust stud in a BMW head after having paid $100 for a gasket and you already tightened down the other bolts.
07-13-2007, 12:49 PM
#4
Lubricious
Join Date: Oct 2003
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Been there, done that. Broke the petcock on a Ford Escort. Stupid little plastic piece. Had to practically disassemble the car to replace the stupid thing.
Lol, try bleeding the brakes on a 15-year old car in a Rust Belt state. It took many a snap before I realized that new calipers were really a better idea when working on a(n) (ab)used car.
Lol, try bleeding the brakes on a 15-year old car in a Rust Belt state. It took many a snap before I realized that new calipers were really a better idea when working on a(n) (ab)used car.
07-13-2007, 05:38 PM
#7
An RX ate my baby
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They do get brittle with age, and if somebody used any Bar's Leak in the radiator, the o-ring sticks to the seat and you snap off the head when applying torque to the thing.
I prefer the ones in other cars that have a wing top instead of a hex head- hex heads invite monkeys to tighten them. Wing nut heads invite you to leave it hand-tight.
I prefer the ones in other cars that have a wing top instead of a hex head- hex heads invite monkeys to tighten them. Wing nut heads invite you to leave it hand-tight.
07-13-2007, 07:04 PM
#8
2004 Winning Blue GT
Thread Starter
They do get brittle with age, and if somebody used any Bar's Leak in the radiator, the o-ring sticks to the seat and you snap off the head when applying torque to the thing.
I prefer the ones in other cars that have a wing top instead of a hex head- hex heads invite monkeys to tighten them. Wing nut heads invite you to leave it hand-tight.
I prefer the ones in other cars that have a wing top instead of a hex head- hex heads invite monkeys to tighten them. Wing nut heads invite you to leave it hand-tight.
Using a special drill set to get the screw out is definitely faster if you have the tools. Use it if you have it.
07-13-2007, 07:16 PM
#9
2004 Winning Blue GT
Thread Starter
I tried a variant of the hammer technique while under the car. Unfortunately, I didnt jack the car high enough to give me enough room for a well aimed swing, and I ended up gouging out a chunk of the screw (which made it even harder)
Yeah, I'm a noob.
Yeah, I'm a noob.
06-06-2021, 03:22 PM
#10
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Thank you!!
This is a set of instructions on how to get yourself out of a tight spot
If you've read the threads on doing your own coolant change and flush, then you've likely seen the comments that suggest
that the drain plug / drain **** can be broken by overtorquing it. And now I can speak from personal experience- yes, it is possible, and it is a major PITA to fix. Better yet, I called Mazda and the service guy laughed and said he had never heard of anybody doing such a thing.
So you were most likely reinstalling the plug, and in the process of screwing it back in, you feel the plug give way. Lo and behold, you're holding the head in your hand and the screw is @$^&@ stuck inside the bottom of your radiator.
First off, take a deep breath. All is not lost, but you'll need to do a little bit of work. It is possible to remove the broken plug yourself and install a new one.
If you need to drive the car, it's still possible to do so (though you will be leaking coolant). Simply fill your radiator up with distilled water and drive away. Feel free to add a little antifreeze, but dont put in much because you'll need to drain everything again very soon. Make sure that you run the engine a bit and keep on adding water to make sure that you have too MUCH coolant. Driving for half an hour will easily leak a quart of coolant, and its better to have a messy engine than an exploding one. Check the coolant level before you go anywhere.
It's also possible to patch the bottom of the radiator, but I was unable to get the leak to stop completely. It's cheaper to just buy another couple of gallons of distilled water.
The next thing you need to do is look for a replacement drain plug. The drain plug is a standard Mazda radiator plug (10mm, 1.25 thread). I was unable to find to exact copy with the same part number, but don't worry- just look for a general Mazda plug. I found mine at a specialty auto hardware store. This shouldn't cost more than $5.
Now that you have a replacement, it's time to get the original plug out. Yes, it is possible! It took me two hours to do it, so make sure you're ready to lie under the car for a long time. Use a sharp knife for this step; I used the long blade on my trusty Leatherman. Stab the base of the screw with the tip of the knife. Try to get it in as far as possible and as off center as possible. If you use the center, you'll end up just gouging bits and pieces of the screw when you slip. Once the knife is in, attempt to twist the remains of the plug out (lefty loosy!). If the screw does not move initially, try digging deeper and apply pressure from an angle, not straight up. Do not stab in another location unless the current one really doesn't work, because the more cuts you make, the harder it is to get leverage.
Once the plug starts turning, DO NOT TAKE A BREAK. Resist that urge to breathe a sigh of relief and wipe your forehead. Instead, apply even more upwards pressure and start turning with gusto. Coolant may start coming out from the screw (if you refilled your radiator), and it will quickly get slippery. I took a break after the first quarter turn and failed to get any more movement for another 30 minutes.
The rest of this should be pretty obvious: remove the screw, take care to wear goggles and gloves if you expect coolant to come out, wait for everything to drain, and install the new plug.
Congratulations! You've spent less than $10+a few hours on this fix, and didn't end up buying a new radiator or something equally extreme.
I'll post pictures when I get a chance.
Hope this helps somebody. I spent 4 days running around like a chicken with its head cut off (including patching the car at 6am before going to a wedding, and better yet, doing the final fix an hour before leaving for a track day). I went through a number of temp solutions that all leaked, so skip that trouble and just use this straightforward process.
EDIT: Note that using a pocketknife isn't the best solution in the world. As others have pointed out in this thread, if you have a special drill set for getting broken screws out, use it and you'll skip the hardest part of this process.
If you've read the threads on doing your own coolant change and flush, then you've likely seen the comments that suggest
that the drain plug / drain **** can be broken by overtorquing it. And now I can speak from personal experience- yes, it is possible, and it is a major PITA to fix. Better yet, I called Mazda and the service guy laughed and said he had never heard of anybody doing such a thing.
So you were most likely reinstalling the plug, and in the process of screwing it back in, you feel the plug give way. Lo and behold, you're holding the head in your hand and the screw is @$^&@ stuck inside the bottom of your radiator.
First off, take a deep breath. All is not lost, but you'll need to do a little bit of work. It is possible to remove the broken plug yourself and install a new one.
If you need to drive the car, it's still possible to do so (though you will be leaking coolant). Simply fill your radiator up with distilled water and drive away. Feel free to add a little antifreeze, but dont put in much because you'll need to drain everything again very soon. Make sure that you run the engine a bit and keep on adding water to make sure that you have too MUCH coolant. Driving for half an hour will easily leak a quart of coolant, and its better to have a messy engine than an exploding one. Check the coolant level before you go anywhere.
It's also possible to patch the bottom of the radiator, but I was unable to get the leak to stop completely. It's cheaper to just buy another couple of gallons of distilled water.
The next thing you need to do is look for a replacement drain plug. The drain plug is a standard Mazda radiator plug (10mm, 1.25 thread). I was unable to find to exact copy with the same part number, but don't worry- just look for a general Mazda plug. I found mine at a specialty auto hardware store. This shouldn't cost more than $5.
Now that you have a replacement, it's time to get the original plug out. Yes, it is possible! It took me two hours to do it, so make sure you're ready to lie under the car for a long time. Use a sharp knife for this step; I used the long blade on my trusty Leatherman. Stab the base of the screw with the tip of the knife. Try to get it in as far as possible and as off center as possible. If you use the center, you'll end up just gouging bits and pieces of the screw when you slip. Once the knife is in, attempt to twist the remains of the plug out (lefty loosy!). If the screw does not move initially, try digging deeper and apply pressure from an angle, not straight up. Do not stab in another location unless the current one really doesn't work, because the more cuts you make, the harder it is to get leverage.
Once the plug starts turning, DO NOT TAKE A BREAK. Resist that urge to breathe a sigh of relief and wipe your forehead. Instead, apply even more upwards pressure and start turning with gusto. Coolant may start coming out from the screw (if you refilled your radiator), and it will quickly get slippery. I took a break after the first quarter turn and failed to get any more movement for another 30 minutes.
The rest of this should be pretty obvious: remove the screw, take care to wear goggles and gloves if you expect coolant to come out, wait for everything to drain, and install the new plug.
Congratulations! You've spent less than $10+a few hours on this fix, and didn't end up buying a new radiator or something equally extreme.
I'll post pictures when I get a chance.
Hope this helps somebody. I spent 4 days running around like a chicken with its head cut off (including patching the car at 6am before going to a wedding, and better yet, doing the final fix an hour before leaving for a track day). I went through a number of temp solutions that all leaked, so skip that trouble and just use this straightforward process.
EDIT: Note that using a pocketknife isn't the best solution in the world. As others have pointed out in this thread, if you have a special drill set for getting broken screws out, use it and you'll skip the hardest part of this process.
anyways, I first tried the screw idea I saw somewhere in this thread or another thread, then I tried the knife thing as suggested. It just wouldn’t budge. So, then before giving up I noticed I had some screw eyes. I screwed it into the center of the broken plug, took needle nose pliers and was able to grab onto the eye part and gave it a 1/3 left turn. I then popped the sucker right out! I was so excited that I yelled out “ I got It!!” Even though nobody was around. 🤣😂
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