Overflow tank missing?

[Calvin C.]

I have a 69 coupe, 350/300, non air car. I baught it from the second owner, it had 64000 miles, and the only major part change is a brake caliper. I am restoring it and I do not remember removing a overflow tank and there are no brachet mounting screw holes like the assembly manual shows, what am I missing? See picture

https://www.forums.ncrs.org/attachme...1&d=1272599361





thanks

cal

[Alan S.]

Re: Overflow tank missing?

Hi Cal,
Is your car a 4-speed or automatic? I believe that would affect what radiator (aluminium or copper) was installed and thus what expansion tank (aluminium, brass, or none) was used.
Regards,
Alan

[Calvin C.]

Re: Overflow tank missing?

The car is an automatic. The ncrs tec info manual indicates the expnsion tank is aluminum for a 69 300 horse, but it looks like there was no tank installed.

thanks

cal

[Michael W.]

Re: Overflow tank missing?

My copy of the judging guide shows 300HP with auto as having a copper rad. That would rule out the use of an aluminum expansion tank.

[Joe L.]

Re: Overflow tank missing?

My copy of the judging guide shows 300HP with auto as having a copper rad. That would rule out the use of an aluminum expansion tank.

Mike and Cal------



Absolutely correct. 1969 small blocks with THM-400 used a copper/brass radiator and no external supply tank was used with this radiator. In fact, there are no fittings on that radiator for an external supply tank, so even if one were to install the supply tank, there would be no way to connect it. The small block aluminum radiator cannot be used with a THM-400 equipped car because there are no fittings for the transmission cooler lines.

1969 300 hp with M-40 and/or C-60 use the copper/brass radiator. 1969 L-46, the only other small block available that year, use the same copper brass radiator if equipped with C-60. Also, many 1969 L-46, particularly later-built, use the copper/brass radiator even if not C-60-equipped. There were no 1969 L-46 built with M-40 so that combination is non-existent.

[Calvin C.]

Re: Overflow tank missing?

My copy of the judging guide shows 300HP with auto as having a copper rad. That would rule out the use of an aluminum expansion tank.

That would explain it, but where did you find that in the judges manual. I located the copper radiator but not where it says copper radiators have no expansion tank.

thanks

cal

[Lynn H.]

Re: Overflow tank missing?

That would explain it, but where did you find that in the judges manual. I located the copper radiator but not where it says copper radiators have no expansion tank.

thanks

cal

Cal,
I have an older 68/69 judging manual (second edition) and the information concerning radiator usage is in item 19 of the Mechanical section, under Radiator. I can see where in text it is somewhat difficult to understand, but they have a chart that depicts radiator usage with different motor/trans/AC options. They list the radiators as being either A, or C. A being aluminum, and C being copper radiators. Then under the Expansion Tank paragraph, they have another chart with tank usage with A, B, and N designations. A, being the aluminum expansion tank, B for the brass tank, and N for no tank used. Hope this helped.
Lynn

[Joe L.]

Re: Overflow tank missing?

That would explain it, but where did you find that in the judges manual. I located the copper radiator but not where it says copper radiators have no expansion tank.

thanks

cal

cal-------


One of the things that confuses things is that the 69-72 big block copper/brass radiators did use an external supply tank. However, the 1969-72 big block copper/brass radiators were the only copper/brass radiators EVER used on a Corvette which also used an external supply tank. NO other copper/brass radiators EVER used on a Corvette used an external supply tank----not a single one.