Opinions / thoughts on condition of this late 1966 Expansion Tank (photos)

[Scott S.]

Hey guys, it has been a while since I have posted. I came across an expansion tank that is dated 66L (November 1966, if I remember correctly), which should be acceptable for my early January 1967 build date.

What do you guys think about the condition, based on the photos?

[Gary B.]

For an original, survivor part, it looks pretty good to me. No pin sized or smaller holes anywhere? Will it hold 15 psi?

Gary

[Scott S.]

For an original, survivor part, it looks pretty good to me. No pin sized or smaller holes anywhere? Will it hold 15 psi?

Gary

Hey Gary, good to see you!

I asked the owner if there had been any repair work done to the expansion tank, and if it had been cleaned to the extent that the original 'patina' (for lack of a better word) has been scrubbed off, or if it had just been wiped clean of surface grime.

He replied "No repair has been done to it to my knowledge looks very original. It was just cleaned no abrasive material used to clean it."

I was wondering mostly about the tube connection at 11 o'clock, if you are looking at the front of the tank. In picture #4 and picture #6, I'm not sure if the weld is original, or whether it has had some kind of repair at some point. The other welds are smooth, but that one looks like some kind of gray material (e.g., something like epoxy) is under the welded area. Also, there is what appears to look like a 'bead' at 12 o'clock (in the weld area) in picture 4, and another similar 'bead' directly below the thumbnail of the person holding the tank in picture #7, also visible from another angle in picture #8.

I don't know if I'm just seeing things because I'm paranoid from so many disappointing purchases over the many years of restoring the car, or if it's something that might be obvious to those with experience welding aluminum, or just more experience than me with these expansion tanks.

Also, the aluminum in this example seems somewhat shiny, more so than the expansion tank I have (not original to the car) dated 67A, which has a much more dull or flat silver-gray appearance. I don't know if both are normal, or if the comparatively shiny example shown in the photos here indicate that it has been polished at some point, before the current owner acquired it.

[Gary B.]

Scott,

Tomorrow I’ll retrieve the original ‘66 expansion tank from its storage box. I recall it has a 66 G date so pretty close to 66 L. My tank should give us an idea what the original welds looked like.

Gary

[Scott S.]

No pin sized or smaller holes anywhere? Will it hold 15 psi?

Gary

The seller's description: "1966 Corvette Expansion Tank 3155416 Harrison Dated 66L + AC Delco Cap Original. This is an original tank not an aftermarket copy. Sold as is, there is NO visible deterioration of the aluminum. Please make sure this is the correct item you need before purchasing. Please look at pictures for details and condition."

Guessing no way to know whether it will hold 15 psi without installing it. Seller's description ("there is NO visible deterioration of the aluminum") should hopefully rule out any pin sized or smaller holes. Everything with these old parts is a crap shoot. The expansion tank I have (dated 67A) is a pretty nice example, but the car was built January 11, 1967 and the JG says the tank should pre-date the build date. 67A is essentially the same as the build date, while 66L or 66M would probably be typical.

The original radiator was stamped 66M.

From the survey data in Noland Adams' Restoration & Technical Guide, Vol. 2, page 446:

VIN ........................ Radiator .......... Surge Tank
194677S 106631 ..... 66M .............. 66L
194377S 106636 ..... NA ................ 66L
194377S 106838 ..... 66M ............. 66B
194377S 107569 ...... NA ............... 66K
My VIN is between the VIN above and below (1078xx)
194677S 108548 ...... NA .............. 66L
194377S 1088 17 ....... NA .............. 66L
194377S 109958 ...... 66M ........... 66G
194677S 110140 ........ NA .............. 66M
194677S 110798 ....... 67B ............ 67A

The first surge tank in the survey that was dated 67A was reported on VIN 110798, or roughly 3,000 Corvettes after mine.

[Scott S.]

Scott,

Tomorrow I’ll retrieve the original ‘66 expansion tank from its storage box. I recall it has a 66 G date so pretty close to 66 L. My tank should give us an idea what the original welds looked like.

Gary

Thanks Gary, I appreciate it! 👍

Here is a close up of picture #4. The weld doesn't look uniform like the other weld (or like both on my 67A example). There is what looks like a gritty gray putty-like substance in the weld area in the attached photo, along with the 'bead' at 12 o'clock, which makes me wonder if those are signs of repair.

[Gary B.]

Scott,

Here’s the original, uncleaned tank from my July build ‘66. Each weld has one or more little goobers. Not perfect welds. But my guess is the tank you’re looking at has been repaired.

Gary

[Scott S.]

Scott,

Here’s the original, uncleaned tank from my July build ‘66. Each weld has one or more little goobers. Not perfect welds. But my guess is the tank you’re looking at has been repaired.

Gary

Thanks very much Gary. That's what I was afraid of, and why I wanted a pair of experienced and unbiased eyes to look at it. The search continues!