'65 Expansion Tank Date Coding

[Clark K.]

I am going over my '65 Coupe with a "fine toothed comb" called the NCRS "Judging Guide". Man, am I learning about my car! I noticed that my A/C compressor is a '66 unit, or at least the label's coding indicates this. So, I will need to change out the label, not the compressor.

I noticed something odd when I checked the date code on my expansion (surge, overflow) tank. The code is 85 C. According to the Judging Guide, this tank is coded for being made in March, 1985! What is a twenty year newer tank doing on my car? I can only speculate that the original tank was replaced with this current one by a former owner.

But, before I spend $195 on a reproduction that is date-coded properly, can anyone confirm that I am reading this code correctly? Thanks.

[Tom H.]

Re: '65 Expansion Tank Date Coding

Don't have my guide handy, but I suspect you are right that this tank was replaced with a unit made and dated in the 80's. Not unusual.

[William C.]

Re: '65 Expansion Tank Date Coding

If I were you, I'd take a good look at that compressor if you have the system apart, '66 compressors were different from '65 in that the main case of the '65 compressor is swedged to reduce the diameter toward the from of the compressor, where the later units have a case that was two piece welded construction. Any '65 judge who knows anything about an original a/c system will catch the compressor in an instant, even without checking the date on the rear plate.

[Clark K.]

Re: '65 Expansion Tank Date Coding

In regard to the secondary concern, the A/C compressor:

The compressor housing is one-piece. There is no evidence of this housing being welded together or otherwise made up of two pieces. The rear casting shows the correct numbers, but I cannot read the date code above these numbers, with the hoses in the way. The compressor is installed, not out of the car or otherwise dissasembled at this time. The label shows incorrect numbers. The model on the label shows the incorrect number for the L76 engine. I have already posted that the date code is for 1966. The rear of the compressor has the muffler installed as described in the judging guide.

Anyone have any ideas how best to correct the problem with the A/C compressor? Label change or compressor change?

[William C.]

Re: '65 Expansion Tank Date Coding

The original compressor labels are not accurately reproduced, but there is a reproduction that is much better than using the later style label. If you have the correct one piece compressor body, and especially if the date on the rear is correct, I'd use the best available label and let it be.

[Clark K.]

Re: '65 Expansion Tank Date Coding

Thanks, Bill. I agree that it would be best to just buy a reproduction label (in this case, a set of two labels) rather than going to the expense of buying another compressor, expecially since the repro compressor would then need a repro label set.

The existing compressor has the correct yellow ink stamping: OK Final Test" in a circle with "Chev" underneath. So, everything looks good EXCEPT that compressor label. A previous owner must have installed a Nov. '66 compressor which might be the same (?) as installed on a Feb. '65 Corvette. This would explain the incorrect label.