Replacing freeze plug - block flush question

[motoMark]

I'm doing the ole freeze plug by the starter and boy did I find a lot of junk in the block. In fact when I drilled a hole in the plug for the screw, not much came out besides a trickle of black goop. Coolant finally came out once I whacked the screw with my little slide hammer.

 

No doubt I need to flush the block in that area as best I can, so would I just stick a garden hose in the hole and blast water in there for a while till it runs clear? Not interested in pulling any other freeze plugs since they all look good with no signs of corrosion like the one I'm replacing.

 

Any tips?

 

Thanks,

Mark

 

[andyd]

I know its a PITA but the others will eventually join their friend in leaking.......I ALWAYS replace old plugs with brass ones, , 1 & 5/8th diameter from memory........as for flushing it out, yep, stick a hose in there and squirt away, it would be idea to replace the other plugs at the same time but I understand your reasoning........lol.........andyd

[Dan Hiebert]

I replaced the same plug about ten years ago, just the one.  I sort of recall that the discussion at the time figured that there is a different gap between the cylinders in the water jacket there that tends to attract more crud.  I flushed it out from both directions, first, I had already removed the thermostat housing and thermostat, so I flushed it out from the top.  Ran the good ol' garden hose until the water came out of that plug hole clear.  Then I flushed it back the other way, running the hose into the plug hole.  That loosened a bit more crud, and I finished by flushing from the top again.  Then you should be watchful on the rest of the plugs for a little while, because you may have removed some crud that was keeping other plugs from leaking.  I haven't had to replace any of the others...yet.

[Booger]

Damn! Thats a sci fi film! set up an oil filter while your in the neighborhood. You got the bracket right there

[Los_Control]

Could be you just change the one plug & be done with it .... This is the lowest area of the block .... all the crud settles here.

You could remove the plug above it and a wire coat hanger, a hose and fish & flush.

 

It is common for casting sand from when the block was born to collect here .... the black dirt you see. Some engines seem to have more then others.

Some engines have already been cleaned.

 

You can imagine with the amount of space this crud is taking up, is less coolant your engine holds.

Well worth the $3 to pull the top plug to run the hose into while fishing the crap out with a wire from the bottom plug

 

Myself, I had a overheating issue. I pulled the water pump & all welsh plugs ... Running the hose through the water distribution tube & fishing with wire .... I'm glad I did.

 

At least pull the top plug and fish wire through the block .... will be surprised how deep the crud builds up over 70 years.

[motoMark]

2 hours ago, Booger said:

Damn! Thats a sci fi film! set up an oil filter while your in the neighborhood. You got the bracket right there

Sure is! The car does have an oil filter, I just took it off to get at the plug.

[9 foot box]

   The freeze plug ahead of the distributor has the same amount of crud behind it. I had to clear the left side of my block to clean it and brush paint the block with Eastwood silver ceramic engine paint. It’s not that hard to do. You could do the same thing as long as you’re doing it. I would change at the least, both bottom plugs. Melling sells a MEP14B, 1 5/8” brass freeze plug. If you buy them from Rockauto, heck, I’ll buy the other five. If you can hook up a hose to your hot water tank, you can flush the block and your water heater at the same time. Do it right the first time and you don’t have to worry if another freeze plug will fail. Sometimes a length of inner speedometer cable can be used to loosen the sediment if wire doesn’t work very well. IMO. Rick D.

[Booger]

12 hours ago, motoMark said:

Sure is! The car does have an oil filter, I just took it off to get at the plug.

Youre exactly right. It gets really tight down there. I had some braided oil lines made for oil filter ended up not using. Just no room with the stoopid close placement of in and out ports

[White Spyder]

Lucky you. I have the oil filter mounted in such a way that it blocks access to that plug. What a PIA it was to change. I had to remove the filter and the lines. Then there was no roon to drive the plug into place with a drift and hamer. Bought an air hammer to get the job done. 

[motoMark]

On 4/21/2023 at 8:40 PM, White Spyder said:

Lucky you. I have the oil filter mounted in such a way that it blocks access to that plug. What a PIA it was to change. I had to remove the filter and the lines. Then there was no roon to drive the plug into place with a drift and hamer. Bought an air hammer to get the job done. 

I was able to use my 36" long 3/8" extension to drive the plug in from inside the wheel well. There is a bit of a gap between the top of the frame and the bottom lip of the inner fender, and I was able to sneak the extension in through that gap to the plug. It was at a bit of an angle to the plug, but it worked out just fine. A couple of good hammer hits and the plug was seated.