Lower Radiator Tube Port?

[Elwood]

Any one know the purpose of the port with the pipe plug in the lower radiator tube, p/n 7707281? The illustration in ORD 9 SNL G-741 January 1954 shows this part without the port, but the one in my '54 M37 has it. I don't think I've seen an M37 without the port, but always with the pipe plug in place. Is it just for coolant system flushing?

It's the circled part in this photo:

[rtkjmk]

It is used for the fender mounted heater /defroster . Most of the original tubes have the plug , a lot of the replacement tubes sold by the various vendors do not .

[Cal_Gary]

Some of our members plumb their cab heaters through it as well. Mine did not come with the bung so I plumbed mine through the water pump.
Gary

[w30bob]

rt,

That's what I thought to.....that it was used for the heater........but it's not. I looked in TB9-2855-45 "Hot Water Heater Installation" and the heater is not plumbed to that bung on the tube. So I don't think we've figured this one out yet.

regards,
bob

[Elwood]

I think I've finally answered the question as to what this pipe plug is for:



Used for the power plant heater kit.

[Cal_Gary]

Good info to know-thanks for sharing!
Gary