4R5

My ’71 VC radiator’s right tank is stamped OW, nothing on the left tank, no tag except a rebuild tag. Is the OW tank correct? The original tag code would have been SU per the Assembly manual (the Service manual says EB) with a 3017282 part number. This was used on all ’71 Cutlasses with the 455 & a/c (not 442). Would appreciate if someone with a ’71 455 a/c Cutlass or VC and the original radiator look to see what the tank codes are. And if you have the original tag, does it say SU or EB or? Thanks!

Mr Shifty Sidney

According to my notes the OW tank is correct for a "ZK" radiator. The ZK was the required radiator with Y72 (heavy duty cooling and generator package). Hope this helps.

Don W

RocketDevo

The driver side tank on 4 core radiators is 99% embossed with "IF" or is blank. The rad tag code can tell you the tanks, but unfortunately it does not work the other way around. As Don has mention the embossed passenger side tank with "OW" would denote a "ZK" rad code tag that comes with the Y72 package. The "EB" rad code tag has the "IF" and "CP" for passenger side tank. It is a 442 rad code only. To further narrow it down the "SU" rad code tag would come with cars that have AC and either the L30 or L32 engine option. The "EF" rad code tag would be used when available as a replacement for the "EB" rad code tag on 442's. It is extremely hard to find original radiators with the tag still attached.

2blu442

I've got a 1971 Cutlass flat top wagon that came with a 350 2bbl. But it also came with the Y72 cooling option that the other guys talked about. It still has the tags on it and the two large letters are ZK, then the left side of the large tag also has IF, OW, 74 Then the letters embossed in the tank is OW.

Hope this helps.
John

4R5

Thanks for the replys.

RocketDevo, if I read your response correctly, the driver tank is almost always either stamped “IF” or no stamping at all, correct?.

John (2blu442), was there any code stamped on the driver’s tank? It sounds from your reply that it’s not stamped, but could you verify that? If it’s not stamped that would jive with RocketDevo’s response.

So it turns out, I didn’t realize it, but this car has the Y72 package, based on the location of the washer reservoir and that it has an original coolant overflow reservoir. The original alternator and water pump are long gone so I can’t verify the 55A alternator and the 407586 casting # water pump. But based on the OW passenger tank code and the lack of a code on the driver’s tank, it looks like the tanks are original, and for the Y72. I checked, it is a 4 core for sure. Now to find a ZK tag....

4R5

One thing I also found is the 1971 SPECs book says the Y72 package includes the transmission cooler, but the assembly manual shows that option (M55) was deleted for '71. I assumed since I didn't see the trans cooler that the car did not have the Y72.

RocketDevo

That is correct, the driver side for the 4 core is either blank or "IF" embossed. The 3 core tank follows the same pattern, either blank or "IA" for the driver side. The external transmission cooler is a very rare option in a A body in any year.

RocketDevo

Here is a photo of the "ZK" rad tag showing the corresponding tanks. Above the tag you should see the "OW" embossed.

4R5

Thanks RocketDevo for the info & picture! Are you interested in selling that radiator?