351m block drain locations

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Jul 28, 2019 | 10:49 AM

packagerjr

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351m block drain locations

Attached is a picture of what I think this the driver’s side block drain plug. I could not feel the passenger side plug around the starter but haven’t dropped it yet. Can someone confirm the location of the passenger side plug? Thanks.

1980 Bronco, 351m

Jul 28, 2019 | 12:29 PM

Tedster9

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From: Waterloo, Iowa

I think so. Pipe thread gives it away.

Jul 28, 2019 | 01:58 PM

77&79F250

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From: S/W Missouri, Polk county

A block drain....that's a new one to me. I'd take it out, and if water/antifreeze comes out, bingo. If oil comes out, not a block drain.

Jul 28, 2019 | 02:24 PM

Tedster9

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From: Waterloo, Iowa

It's good to check or clear them in older engines, rust sediment and scale buildup becomes a problem though it wasn't a problem when they were new.

Jul 28, 2019 | 03:41 PM

FMJ.

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From: Cape Town, South Africa

It's a coolant drain plug.

The passenger side one will be at the front just under the exhaust manifold.

When you drain the block, drain the radiator first.

But stand back anyway coz the block holds a f$$k load of coolant, and there will be a mess.

Jul 28, 2019 | 05:26 PM

packagerjr

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Thanks group. I was surprised to see coolant at the thermostat when I removed it after draining the rad, but guess it’s the way the system is designed. Plus I got maybe 6 quarts out the rad which told me I’ve got more elsewhere.

Best I can tell, the drivers side looks like a 1/4” pipe plug. I’d like to pick up a dedicated socket just to reduce chance of round off. Can anyone confirm the size?

thanks.

Jul 28, 2019 | 07:38 PM

Ozzie H.

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From: S.E. Louisiana;so far USA

Quote:

Originally Posted by packagerjr

You're lucky that they are square heads. My 460 had recessed Allen sockets, which rounded out when they were attempted to be removed after 42 years, requiring drilling out. I don't know the size. You can measure the size and buy an 8 point socket that size. If you flush/drain frequently you can put a valve in place of the plug. It makes cooling system flushing much easier and efficient. If it's never been out in 40+ years, it will likely be full of crud, and you'll have to dig it out with a wire. You may want to wear safety glasses or a face shield when doing the work. Sometimes it will come with a gusher. As mentioned, drain the radiator first.