Questions about replacing a freeze plug

[sdyck]

I have a pretty good coolant leak from the freeze plug closest to the oil dipstick.  This will be the first time I've tackled a freeze plug so I have a couple of quick questions.

 

First, I'm planning on draining the rad and then the block, but I've heard its difficult to remove the engine coolant drain plug.  To access the plug I'm going to have to remove the passnager side heater lines and pipe that are in the way as well.

 

Do I have to drain the block via the engine drain plug or would it be easier to just be ready to catch the fluid as I remove the heater lines and the freeze plug itself?

 

Second, looking at the system it looks to me that the high level of the rad is high enough that the engine should refill fairly easily, and if I run the engine, it should fill any voids pretty quickly. Is that correct.

 

Thanks for the help.

 

Steve  

Edited April 29, 2015 by sdyck

[Zed Head]

Core plug.  From the casting process.

 

Anyway, no real need to remove the drain plug.  I wouldn't, too much trouble.  I wouldn't even remove the heater lines unless you plan to replace them because they're old.

 

On the other hand if you plan to flush the block or something then removing the drain plug might be a good idea.  I removed one from an engine on a stand, using a long handled wrench.  Not terrible, just requires lots of leverage.  I used a 7/8" wrench, but I think it's actually 22 mm.  Hex head bolt style, not the funky square ones.

 

How do you plan to remove the core plug?

[hr369]

I just went down this path you're going. I replaced just 1 and soon after another one popped. It popped in a very inconvenient place too.

Lesson learned:  If 1 is bad the rest are not far behind.  Also, after you replace them they may leak a little bit. Don't panic and rip them out again because sometimes

it takes a few heat cycles to seal completely. 

 

The hardest ones to replace are on the intake manifold side. On my 280 I had to remove the intake manifold to get to them.

If you're going to keep the car forever you might consider going with brass. Seeing that you're up in Alberta i'de see what everyone

up there uses. Rumor has it that brass doesn't pop out in extreme cold. But thats internet folklore.

[sdyck]

Thanks, I will be using brass plugs and plan on punching it out with a blunt chisle. Will tip the plug outwards at the top by driving it in at the bottom.  

 

Hr369, did you empty the block first or just let it run out when you removed the plug? I'm not sure what to expect when I remove the plug, its just weeping a little right now. Will I get a gush of fluid as I remove it if I don't drain the block?

 

I'm still going to try just the one for now the others look good. At some point I'm going to have to remove the carbs to clean them up and I may deal with all the plugs at that point.

 

Thanks.

[siteunseen]

On both my 72s the plug is on the drivers side at the rear below the #6 cylinder. I took mine out after draining the rad and a $^!# load came out.

[hr369]

Thanks, I will be using brass plugs and plan on punching it out with a blunt chisle. Will tip the plug outwards at the top by driving it in at the bottom.  

 

Hr369, did you empty the block first or just let it run out when you removed the plug? I'm not sure what to expect when I remove the plug, its just weeping a little right now. Will I get a gush of fluid as I remove it if I don't drain the block?

 

I'm still going to try just the one for now the others look good. At some point I'm going to have to remove the carbs to clean them up and I may deal with all the plugs at that point.

 

Thanks.

I removed the drain plug. if yours is frozen and you can't get it out, you could try blowing the remaining water out by using compressed air.  They may look good from the outside but mine were rotten from the inside. You could try sticking an ice pick into them to see if its about to rust thru if this is your daily driver.

when these things go it empties the radiator fast. carry a couple litres of water in the car just in case.

Edited April 30, 2015 by hr369

[rossiz]

i'd pull 'em all out and flush the block - you'll be shocked at the crud that will come out. then replace with a set of brass ones. they're cheap and you will be much happier knowing your block is getting good circulation. you can drive one side in and the other pivots out, then grab and yank w/pliers. stubborn ones you can drill a hole in and tap a drift pin into it then pry it out. 

 

somewhere on here i posted a thread showing the goop that oozed out of my block when i pulled my plugs - it'll inspire you.

[siteunseen]

somewhere on here i posted a thread showing the goop that oozed out of my block when i pulled my plugs - it'll inspire you.

 

http://www.classiczcars.com/topic/49406-steam-powered-z/page-2

Post #29

Edited April 30, 2015 by siteunseen

[Jarvo2]

Agreed.  Anyone who has not fully cleaned out their 40+ year old engine can expect to see this sludge in there...

[sdyck]

Lovely!  Ok tonights the night to drain the system, had no time last night, but did get a 22mm socket on the drain plug and it turns.

 

Did you guys use a chemical flush with all that crud or just straight water?

 

I know its a good idea to change all the plugs, but if I strip down the engine to get at them all it will take me to mid summer to get it all back together at the pace I work and the time I have. I want to drive!  So its just the one for now and next winter I'll tackle the rest.

 

Thanks

[rossiz]

i had the head off at the time and used a pressure washer (no chemicals, just water) down into each water passage and blew muck out of the frost plug holes, then went laterally between frost plug holes, it kept puking out crud and goop for almost 1/2 hr of flushing, then eventually ran clear. 

[sdyck]

Drained Coolent and the freeze plug is out. Coolent was pretty frsh not much crud came out when I drained the block. Had to quit to watch the hockey game. go flames!