How to Change/replace a Freeze Plug

How to Change/replace a Freeze Plug

Here is a "how to" for the shade tree mechanic, and maybe even the pro mechanic.

It’s been a while since I have written anything, as I have had lightning strike my computer, modem, and router, which put me down for awhile. (Why do people want to move to Florida again?). I am very grateful and fortunate to be blessed with abilities in music and science (machines). The two do have a co- relation.

For example: I have long slender fingers with the coordination to play the piano, but this also comes in handy when I am working on engines. You may be able to relate to this, especially when you get to a nut or bolt that you just can’t get to!

Let’s face it. Some of the vehicles today are insane to work on. Either you have to be a contortionist and triple jointed, or have all of those “special tools” with some wacky number like 2a4487b24. Or a left hand threaded tap wrench with some ridiculous size like 6.5mm. I am sharing this in hopes that it may benefit the “do it yourself-er” or “shade tree mechanic.” For that matter, maybe this would interest a pro mechanic. Then, of course, I may not be the only one who has tried what follows.

I am first going to assume that whoever is reading this has some basic mechanical knowledge. I wish to shed a little light on the “freeze plug.’’ I have rebuilt and/or helped rebuild quite a few engines in my time, and have (like many before me) become familiar with the freeze plug. For those of us not familiar; a freeze plug is usually a round, dish shaped piece of metal, which is pressed or driven into the engine block and the engine head. There are multiple sizes, and usually multiple locations depending on the engine, and its maker.Common freeze plug locations are:

  1.  Behind the block or cylinder heads, obstructed by the transmission bell housing and/or firewall
  2. along the sides of the engine block, usually obstructed from view by the exhaust manifold.
  3. The front of the cylinder heads and block, usually behind the air conditioner compressor, alternator, water pump, and/or belts and pulleys.

A COMMON MYTH ABOUT THE FREEZE PLUG:

It is an expansion device made to prevent damage to the engine in case the water in the engine should freeze. The plug pops out, instead of the engine freezing.

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22 Comments
keyboardologist, posted this comment on Nov 12th, 2007

I had pictures to go with this article, but Triond removed them for some reason. I guess I’ll put them on Picable, or try again.

jak3, posted this comment on Jan 3rd, 2008

clever way to access a difficult fix.

where did you get this type of brass plug ?

I need to do the same repair.

thanks

keyboardologist (writer), posted this comment on Jan 3rd, 2008

jak3, there are several different types of plugs available. there is a rubber expansion type (similar to a plug in a motorboat). And the brass/copper alloy type. The plug I used is copper. I found this at a NAPA auto parts store. These are fairly common, but you need to make sure the person behind the counter knows what they are doing. The “expansion type” freeze plugs have a precise fit. Carefully install this type of plug, as it is soft metal, and easy to break if you overtighten.
Thanks for reading this article, I hope it helps.

Austin Schnelting, posted this comment on Oct 27th, 2008

I got told that if you hit on side of the freeze plug with a screw driver and and a hammer that it would turn then you could twist it out

jon veselka, posted this comment on Jan 1st, 2009

what size motor is your truck cause i have an ‘87 f-150 and im replacing all of the plugs none are corroded but one popped out this past winter(not enough antifreeze in the coolant) so i figured id replace them all but with the big 351 and both headers i cant get to them to pull them or put new ones in i bought the same type freeze plug you describe but the motor mount is in the way and the headers in the way of the plug right above the starter,
i took off the motor mounts and jacked the whole motor up about 2 inches and am now able to reach one side but the other the headers and the starter is still in the way is there an easier way ?

thanks jon

keyboardologist, posted this comment on Jan 1st, 2009

I have a 5.0 liter (302), and no matter how you slice it…freeze plugs are a major pain in the butt to put in or change out. From what you’re telling me, you might have to pull the starter and the header. I got lucky on mine, because the plug was rusted out, so I could get a flat screwdriver in, and pry it loose. If you can get enough room to get a right angle drill in there (with a short bit), you may be able to get a hole in the plug you are trying to remove. At that point, you could get an awl,or a pointed screw driver in it to pry it out. As far as hitting a freeze plug with a screwdriver and a hammer, I would be gentle. If you ding up the hole that the plug goes in, you’re in for a LONG day. The hole must be as clean and smooth as you can get it. I had to use a mirror and a light to see the plug I was changing. If I had the time, I would have pulled the motor, but I figured if the other plugs were o.k. I’d leave them alone.

jboney, posted this comment on Mar 29th, 2009

i cut a hole in the fire wall by the gas pedal in my 97 tacoma to turn a 1200.00 repair into a .50 cent repair . replaced cut out piece with liquid nails i’m currently trying to find a cheap fix for replacing a freeze plug located behind passenger side motor mount

DIpaint, posted this comment on Mar 30th, 2009

working on a 1968 Ford F-100 that has set for years!!I fially got it running ,went to put water in & it ran out the back !!The pu. has set in the same spot! I looked under & found a Freeze Plug!! Can’t find where it goes!! It is fhe 240 cu. 6cyl. can anybody HELP

jeremy, posted this comment on May 31st, 2009

what is the easiest way to replace a freeze plug on a 00 dodge durango i have the part but when i start it it flips and flops around on me is there any special tool i could use to prevent that from happening

keyboardologist, posted this comment on May 31st, 2009

#9 (jeremy), If you can get to the freeze plug (if you have the engine out of the vehicle), you can use a socket that is close to the size of the freeze plug, and center the socket and plug over the hole. You need to hit it as straight as possible, but you don’t want to hit it too hard, or you will bend the freeze plug. I find that the two piece freeze plugs are a lot easier to use.

juan, posted this comment on Jun 15th, 2009

so do u hit one end of the freeze plug then twist it out? or do u poke a hole in the middle and pry it out?

keyboardologist, posted this comment on Jun 15th, 2009

Juan, if you are able to get a hole in the middle of the freeze plug, then you can pry it out. I was lucky in my situation, because the freeze plug had a hole rusted through it.

Michael, posted this comment on Aug 13th, 2009

Wow, some really useful information here. So here’s my issue, I replaced my engine last year with a used engine (5.0L 305-96 Chevy in a K-1500). My engine overheated, radiator cracked/replaced Rad, hoses, water pump & fan clutch, thermostat. OK! Engine ran perfectly for a while, couple of days actually. I started losing coolant (approx 1.5 gals. every other day). Bottom line, I’m pretty sure the freeze plug above my starter under the manifold is shot. Are there others? And where are they located? Can you tell me where I might find the freeze plug locations, I have looked and I need some diagrams of specific locations

mike, posted this comment on Dec 30th, 2009

i also have a freeze plug dripping, ln a 92 chev sierra pick-up. its located on the passenger side behind the started
will this brass plug work for me?

keyboardologist, posted this comment on Dec 30th, 2009

If you are able to get your hand up there to press it in, it should work. Keep in mind that you will also have to get a wrench in there to tighten it. There are rubber “compression type” plgs available also, which tend to work well in tight spots. It’s important that you get the right size diameter plug however.

John SCB, posted this comment on Jan 24th, 2010

I just traced a coolant leak coming from behind the passenger side motor mount on my ‘92 F150 5.8L. It looks like it must be a freeze plug as I’ve checked all other coolant system sources.

My question is: If I remove the engine mount to access the plug, where is the best place to support the engine on a jack? And, is it safe to remove just the one motor mount or should I do them both to eliminate any stress.

Any other tips on this procedure would be much appreciated.
Great write-up here and thank you!

John in SoCal

jeelocked, posted this comment on Mar 4th, 2010

Good topic thread info.

I will be replacing several (if not all) the freeze plugs on 1994 Lincoln Town Car. I have the replacement plugs in hand and the car up on blocks. (I will be calling for the compression type replacement plug $prices shortly.

Here’s my question. Any one heard of a tool purpose built to extract freeze plugs in close working quarters?

If the plug is accessible using a right angle drill and a short drill can be purchased (or made by breaking off a standard length drill and pointing it with a drill sharpener) then someone should by now have designed an extractor, bolt driven like most wheel pullers.

Drill the plug.
Insert the extractor.
Turn the nut (ratchet wrench or ratcheting box end watch-ma-call-lit wrenches)
Pull the plug.

The extractor would have to have semi compressible ‘jaws’ on the working end. Like the common EXACTO blade holders.
The pulling force isn’t much in terms of working tools. Being on a thread ramp, one might turn the thing by hand! Nah use a wrench.

There’s ‘nuttin new here!

Send me a proof of concept model and I’ll beta-test it for ya. . .

Jim, posted this comment on Mar 9th, 2010

SOME mechanic is trying to charge me 577.00 to change 3 freeze plugs in an hyundai sonata 2001 v6…..is that too much? what would be a reasonable price?

Robert, posted this comment on Mar 23rd, 2010

@jim Midas is trying to charge me 200 for 1 so I would assume that’s reasonable.

javier, posted this comment on Jun 12th, 2010

great information, i drive an 84 ford f150, this information is of so much help to me, thanx

darrell turner, posted this comment on Apr 22nd, 2011

There are several locations for freeze plugs depending on engine type..I have had continuos success using a punch & hammer to remove plugs,placing punch to one edge and tap moderatly, don’t go wild & it should twist enough to take long nse pliers & rmove.. Clean hole with fine emery cloth to remove rust and gunk & replace new oe type with a socket of same size or use a sel driver deigned for this job..Some engines need to be jacked up 3 to 4 inches by using jack then undo motor mounts and sometimes while its up go ahead and rmove starter and manifold if necessary, or you stand around and fuss & fight it and MAY not get them in properly & next week you’ll wish you would have gone an ztra step to save the xtra work & pain..Good Luck ,,Be Safe… dt

Debra, posted this comment on Oct 29th, 2011

thanks for all your info – mechanic at Waly-mart never heard of freeze plugs.

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