On my 3.5 the copper radiator plug screw at the bottom is not coming out. It doesn't move at all . Radiator is copper too and very soft metal. When I turn the wrench it is bending the radiator. I can't really put much force on it.
How can I best remove this plug? heat? Well there is still coolant in, not sure if heat will work.

Can you remove the radiator and drain the coolant?

I'd consider drilling it out - but then I don't know if copper replacement plugs are readily available...

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Get the lower hose of and drain the coolant that way. Take the radiator out and worry about the plug later. It is probably heavily corroded in the threads. Not worth risking a radiator if you can drain coolant through hoses (standard procedure in a lot of cars that don't even have drain plugs anymore). The good news about it being stuck like that is that it will not leak

Bert

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'70 111 280SE/c 3.5 (4 spd manual) - sold
'63 MGB
'73 MGBGT V8

Yeah, I'd just forget about the plug and pull the lower hose... I just went through trying to find a rad for my car that was copper (wrecked the trans cooler) and it wasn't fun.

You can use spray penetrate or a freeze spray to shrink the bolt. Be careful, those old radiators are expensive. A radiator shop can fix it, if any are left that is.

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Regards

Warren

Currently 1965 220Sb, 2002 FORD Crown Vic Police Interceptor

Had 1965 220SEb, 1967 230S, 280SE 4.5, 300SE (W126), 420SEL

ENTER > = (HP RPN)

Not part of the in-crowd since 1952.

Yup, first law of mechanical devices, "If it ain't broke, don't fix it".

I couldn't get mine out, and didn't mess once the brass itself began moving. I pulled the lower hose like everyone else says. My oil cooler plug does, thankfully, come out though.

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Current:
2021 Charger Scat Pack Widebody "Sinabee"
2018 Durango R/T

Previous:
1972 280SE 4.5
2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi"
1999 Chrysler 300M - RIP @ 221k

Thanks so much everyone. I guess I better don't mess with the screw and pull the hose- easy. And yes it is true...the screw doesn't leak at all. Thanks again.

Until recently, all I had to do to drain my oil cooler was start the car.