Radiator overflow tank?
 

Hey Gang,

I’ve been speaking with another member (Pete Chronis) on what was the factory correct radiator overflow container for our 60-66 trucks. I have ordered a generic 2”x16” container to catch my water expansion when needed for now.

According to what we can see or find, most trucks (65-66) came with a larger radiator overflow tank. Classic Parts #78-416 and is reported to fit ’41-54’. This mounted on the right inner fender next to the battery. However, it’s the same design as what was used on a 65-66.

Does anyone in the group have better information?

Re: Radiator overflow tank?
 

Jake, why don't you post those pics I sent you of the factory coolant recovery tank so other members can see what it looks like. The one thing about this tank is it has a protruding nipple on the top while the earlier designs don't, otherwise it's identical from the ones used in the 30's, 40's & 50's.:ok:

Re: Radiator overflow tank?
 

Will try

Re: Radiator overflow tank?
 

This was sent to me by another member and could be an after market unit.

Re: Radiator overflow tank?
 

The Radiator coolant recovery tank was part of the package on all 65-66 Assembly-line installed Factory AC equipped trucks. Was probably an option on bigger trucks too but to date I have never seen one on any GMC that did not come with Factory AC.

Re: Radiator overflow tank?
 

You may have not seen a coolant recovery tank on no AC models but I pulled a factory recovery tank off a 66 1000 series with a 351E that did not have AC. It makes sense that the larger displacement 351E V6 would come with that as optional or even standard equipment over the smaller 305 engine.

Re: Radiator overflow tank?
 

Jake, that is the correct factory recovery tank set up in the pic.

Re: Radiator overflow tank?
 

You don't still happen to have that one do you Pete? These tanks are prone to rust out - I have three of them all off 65-66 factory AC equipped trucks and every one of them has a rot hole of one sort or another in it - I need to find a solid original one

Re: Radiator overflow tank?
 

Yes GMCNUT I still have the tank, I've been kind of saving it. It's no good since it's rusted and full of holes. On another note our banned member Mr. BARRYGMC (AKA Charon) is touting on another site claiming I'm a clown because these trucks never came with a coolant recovery tank:ahhhh: Well your photos prove such did exist and the fact I pulled one out of a 66 GMC:thumbsup:

Re: Radiator overflow tank?
 

With ANY and ALL GMC specific parts there is a GM part number that can be traced to such part, Steve and Pete . Nothing shows up in a Chevrolet parts book , nothing in GMC accessory books from 1960-1966 . The can shown was used 1937-1948 , after that all Ive seen is aftermarket parts which GMC most likely offered in this situation or added by a service station after the truck sold new.

Re: Radiator overflow tank?
 

Yeah, I figured yours was also rotted - BUT - I do need one with a complete label on it to have the label reproduced - all three of mine are missing some section of the label and it can't be scanned to re-create a new one. Is the label complete on the one you have by chance? if so can you post a pic?

Re: Radiator overflow tank?
 

Not sure how to locate the part number for these Jon - I have a huge master parts catalog for GMC through the 60's so I'll see if I can find it. GMC took the time to change the label design for the overflow tanks used on factory AC trucks so I feel like there is a GMC part number in a master parts book but unless it was offered as a stand alone accessory option (which it obviously wasn't) it would not show in the accessory guides, and it would not show in any Chevrolet books unless used on them, and to my knowledge they were not added to any Chevy trucks after 1955. So this is probably a GMC-only item, and with exception of Petes' unusual example they were on all assembly-line installed AC trucks regardless of 305 vs 351. I have found them on both and have collected three tanks off factory AC GMC trucks so far so we can find a part number I feel like - need to see what the master parts book shows us

Re: Radiator overflow tank?
 

How do you know this Steve ? quote " they were on all assembly-line installed AC trucks "

Re: Radiator overflow tank?
 

I've personally owned or found 4-5 factory AC trucks (more than just about anyone in the country) and every single one had one of these tanks on it or had inner fender holes where one had been - so is it possible for any factory AC truck to have come off the assembly line without one? Possibly - but doubtful. Factory AC introduces more heat and strain on the engine, so that is why every factory AC truck also has a 4 flu radiator in it too vs the more usual 3 flu on V6 equipped trucks, so bigger radiator for greater cooling, and an overflow reservoir was added. Plenty of GMC trucks came with dealer-installed AC units and I have so far never seen one of those installations include a reservoir - only assembly-line installed units using the A6 compressor and riveted-in well nuts in the dash seem to have these.

Re: Radiator overflow tank?
 

My question was more at how you know they were on the truck on the assembly line.

Re: Radiator overflow tank?
 

nobody can prove something was on a truck off the assembly line unless they have the ppwk showing it, or they themselves were working on the line and happened to snap a picture - all we can do is observe untouched original trucks for how they appear to have come when all the hardware and related placement etc mirrors that of other known untouched original examples. I have no oubts of any kind that these overflow tanks were installed at the assembly line level and no one can prove they weren't just the same as maybe I can't prove they were.
After seeing several examples of factory AC equipped trucks all having these tanks, it only makes sense that they were obviously part of the standard equipment commonly installed on AC equipped trucks - that's my take on them until someone proves they are dealer installed or something

Re: Radiator overflow tank?
 

The "overflow condenser" shown by Groby and others was definitely an accessory in the 50's and earlier. It was used on vehicles without A/C. It was used in vehicles without special radiators. Just guys adding a neat aftermarket gizmo they didn't need.
If they are "Factory", GMC would have mounted them in exactly the same place with exactly the same bracketry, hoses and hardware; and be the same unit with GMC logo. The fact that they are on A/C truck with larger radiators just means that GMC could have used larger radiators with A/C. Does not mean that the "overflow condenser" was installed at factory. The overflow condenser does not keep the radiator from over heating due to more "heat and strain" anyway. If they used a bigger radiator so that it would handle the A/C "strain", it would handle it.
The examples I see so far on this post show that the units were not mounted the same. They look aftermarket/dealer units.
If the vendors thought it was used in 60-66 they would surely include those years for more sales.
Until it is found on a build sheet or in a GMC document for 60-66, it should not be labeled "Factory", that's my take on it. Just an opinion not hostility.

Re: Radiator overflow tank?
 

What "untouched originals" do we have to look at ? I haven't seen ANY nice original GMCs with AIR that were untouched. I spent a good part of my day looking through 1964 1965 1966 print dated GMC parts books and older books back to the mid 50s , no cans. The only radiator surge tanks I found were for BIG trucks. Zero applications for 1000 to 2500 series trucks and no listing at all to do with AIR. Without a picture of these parts matching these numbers I found, its impossible to say if they are the same ,but the books do not lie. If theres not a part number to application , theres no such "factory" part. The only theory that makes any sense is the can pictured of Steves was a service option made in the aftermarket or one of the BIG truck cans retrofitted to fix customer concerns. To say its factory without proof , or because you had a truck with one , or several , still does not mean it came off the assembly line this way. Every "original part" can be traced. So far , these cannot be.

Re: Radiator overflow tank?
 

The one I pulled off was from a 66 351E with no air conditioning. The setup was exactly the same as GMCNUT's right down to the mounting, I also found it's basically the same tank that was used in the 30's, 40's and 50's. I will check this weekend for any possible part numbers, the label on it is pretty faded out. I seriously doubt these were installed by a service station as they are a real GM Part, more research needs to be done to figure why there was no info listed anywhere.

Re: Radiator overflow tank?
 

Ken / Jon - the GMC factory installed radiator overflow tanks on AC trucks have a special bracket made to fit a very specific spot on the right inner fender behind the battery - in 100% of the cases I have observed including all THREE tanks I pulled and saved here, they were mounted in exactly the same spot. I know you guys don't like to believe the books are ever wrong but they are sometimes wrong I hate to tell you. Jon's 1964 Chevrolet Data book does not show a 327 V8 option for 64 1 ton C30 trucks, but somehow magically he now has one with that very motor and with assembly line installed AC no less - something else hundreds of book believers didn't think could happen. Jon's C30 has all the ppwk showing the 327 and shows assembly-line AC both being ordered for it - so look guys - we can beat a dead horse a thousand times over trivial stuff, but I am telling you from EXPERIENCE - these 65-66 GMC AC trucks have Radiator overflow tanks on them that have been there from day 1 regardless of what the books all say or what the books omitted. The only book any of you can count on is the Bible - other than that, they are often as flawed as those who wrote them.

Re: Radiator overflow tank?
 

The books are not wrong Steve , something you missed in what I was telling you , the Data books are only PART of the story. They do not list every option or combination. They list a base-line , Theres more books needed that complete the story. My March 1st 1964 or 3/1/64 data book did not get the revisions that were available to the dealers and checking the dates of my truck engine, it was built = assembled 3/24/64. My 66 Data bookS , three , are all slightly different with updates. Back to what you said is not in the books , every part of my 64 327 AC C30 is in the GM parts book , every factory piece right down to the last clip washer, original belt numbers carb , you name it. GMC did the same. Data books are not always updated by the dealer but the parts book has every single piece. I found you that 55-58 GMC Suburban gate emblem part number you didn't think existed also. Experience is great Steve , we are all anxious for facts though , something positive to back up a claim.

Re: Radiator overflow tank?
 

I said, if Factory, they would be mounted same, same bracket, same hose, etc. If you found several that were exactly the same, then I would agree it points to what you believe. I don't doubt you at all. It may be trivial but it's what truck guys/semi-purest like us all, like to debate. Like to study, like to give opinions. It's a forum for that. I also mentioned Logo's. Many tanks from the 50's have a winged logo on it that says "Chevrolet". The photo that Jake was sent and posted, seems to have something above the text, could it be a Chevy Winged Logo? The other picture has the exact same wording as the Chevy unit but has no Logo. I did find an NOS one in a box with a Chevrolet part no. of 985528. No Winged Logo. The box says "Chevrolet Accessories". That means not Factory. The Jake picture also shows a modified strap. These were made to mount on a flat firewall and would have to have bracketry to mount on an angled surface. Don't see that. In my previous profession I was trained to double and triple check before making something cast in stone, or in our case, building an accurate database of 6066 info. Test theories, find documentation. It is not easy to be absolutely sure about this issue. Maybe other info will come in to firm it up. I was giving another possibility of why they were on some trucks. I don't have any proof as you already said. I did check the GM Heritage Center (Vehicle Information Kits, no GMC) and as far as I can see, factory coolant recovery systems not mentioned in their kit info for Chevy Trucks until about 1973, for whatever that is worth. Maybe someone has Chevy info.

Re: Radiator overflow tank?
 

Ken , am I reading that Chevrolet Accessories are NOT factory ? in this comment "I did find an NOS one in a box with a Chevrolet part no. of 985528. No Winged Logo. The box says "Chevrolet Accessories". That means not Factory.

Re: Radiator overflow tank?
 

Accessories are sold usually by dealers. Options are factory. If that is what you are asking. I was merely saying that the box says it's an accessory item. It's not a factory item in that case.
This same discussion was started on 67-72 ChevyTrucks site by Jake on 8MAY17. Other members of 6066 are also responding. Some have Chevy Data from 66-66. No recovery tank options or accessories. Others say no factory tanks on 60-66 trucks. The advice there is no factory recovery. The picture Jake posted that he got from a 6066 member is also on there from a guy who saved it from years ago. He is ClassicV6GMC's from Overland Park, KS. I really don't think these are true factory installed. I would have to see one or two in person and examine the mounting and see if it was bent, modified or monkeyed around with. Probably never get the chance to do that. The picture does show the strap kind of designed for the inner fender but I can't see if it was modified and can't see where else its mounted. Can't be just one tie point. I do see evidence it was modified. I see a bolt towards the rear of bracket that looks like the original foot was bent, bolted to the other foot and an extension strap to inner fender was added. A conspiracy theory for sure. If it was made for 64-65 it would not be designed like that. The person adding the tank would have to change or modify the radiator cap for it to work. That modification is described in the 50's Chevrolet literature for the recovery tank accessory.

Re: Radiator overflow tank?
 

Okay , I read that as they were not part of Chevrolet or GMC at all , meaning not GM , my mistake Ken . Accessories are stated as factory original very often , some not put on at the assembly line but Many accessories WERE put on , on the assembly line but could also be bought separately. A great example of that are west coast mirrors. Plenty of pictures of those trucks coming down the assembly line with those mirrors plus they were sold as accessories for dealers to install. Its all in how you ORDERED the truck VS purchased off the lot. What Im going to call "factory AIR" or indash air was another thing sold separately and factory ordered. To find out exactly what was and what wasn't you need to look at dealer order forms , data books etc. As for these catch cans for the radiator , we did find a GM part number for a "radiator surge tank" but the application is C40 and up , diesel , V6 etc . No pictures have been found of those but its possible these were fitted to AC trucks.

As to the other 67-72 forum on Jakes post, Ive been posting on that one also as user ID 60-66.

Re: Radiator overflow tank?
 

Understood. All this is kind of funny when you visualize that advertisement showing the water blowing out the motor. Stating all the specially designed water jackets, water pump and flow volume. The recovery tank lends no performance or cooling to the motor. It is truly an accessory like a Kleenex box holder. It is valuable regarding antifreeze. Don't want that spilling out.
Went thru the entire 1966 Chevrolet truck documentation at GM Heritage Site. Lists all std., optional, RPO and dealer installed items. No recovery tanks. GMC is very hard to pin down as to that info.

Re: Radiator overflow tank?
 

I removed the post to make everyone happy. I'm sorry I started this topic. I really am......

Re: Radiator overflow tank?
 

I suggest everyone else omit any mention of it. I did. Thanks Jake. Your restoration is top notch.

Re: Radiator overflow tank?
 

:goodjob::signthankspin:

Re: Radiator overflow tank?
 

Hate to burst your bubble Steve on not believing books , or that GM books are wrong and didn't record everything, well I found the engine suffix code on my 64 327 C30 ,Steve, UC , in another source from a friend who has all the Flint engine records. You can see that info on the other forum. Been thinking about where we might find these cans , anybody here have GMC service bulletins ? Might be a good place to look .