I'm the proud new owner of a 1972 LT-1 with air conditioning, serial number 137L2S523694. This is only my second corvette, and the first in over twenty years. I know next to nothing about these cars, but am motivated to learn, and very much want to restore this car to it's original condition. I knew my car 's radiator had been re-cored at some time in it's past, but now I suspect that even my end tanks are incorrect. As far as I can determine looking at part numbers, it appears that the 1972 LT-1 equipped with air conditioning used the same radiator as any 72 with automatic transmission. I would very much appreciate hearing from any 72 LT-1 A/C owners if their radiators are fitted with plugged transmission cooling line fittings in the right side end tank. Thank for you help. Mike B.
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Re: 1972 LT-1 with a/c radiator
Michael------
I would not say it could never have occurred but usually cars with manual transmission were not fitted in PRODUCTION with radiators with transmission oil cooler provisions. Additionally, there would have been absolutely no advantage or reason to use such a radiator for cars with A/C if they did not also have an automatic transmission. Of course, I suppose it could have occurred if the factory ran short of the radiators without oil cooler at some certain time but that's the only way I could see that it could have occurred.
However, the radiator without transmission oil cooler provisions was discontinued from SERVICE a LONG time ago and replaced by the version with oil cooler provisions. So, if one needed a replacement radiator and purchased it from GM or Delco, one would have received the type with oil cooler provisions. I expect that's how the one you have found it's way onto your car.In Appreciation of John Hinckley -
Re: 1972 LT-1 with a/c radiator
Joe, thanks for the response. I think you're answer is correct as I just spoke with Drew Papsun and he told me his 72 a/c Bowtie does not have the cooler fittings. The thing that made me question the originality of my side tanks is the fact that there is no drain fitting in the bottom of the right side tank. I was under the impression that all 70-72 corvettes had that drain fitting. I assumed my tanks were correct for a 4 speed as there are no cooler line fittings, but then I discovered the drain fitting was missing. Now I suspect the entire radiator was replaced instead of just a re-core. I'd like to reinstall the proper radiator for my application but I guess I got a little confused looking at the part numbers in that it appeared the correct one also fitted an auto transmission car. That makes sense now after you explained the "no fitting" radiator was discontinued. So now I'm guessing the "correct" radiator for my car would be one out of a 4 speed with a/c, right? And that is a slightly larger capacity radiator than just a 4 speed radiator, right? Then again, I might just say "screw it" and put this one back in. Thanks.Comment
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Re: 1972 LT-1 with a/c radiator
Michael------
I've never seen an original radiator without a drain on one of the tanks although not all were originally fitted with a petcock. In fact, for 1972 I believe the drain was fitted with an elbow and pipe plug. If the radiator is an original GM it should have "Harrison" embossed on one of the tanks. This is quite large and easy to see.
The correct radiator for your application is a GM #3018803. This radiator was used on ALL 1972 LT-1 applications, regardless of whether the car had A/C, or not and had no oil cooler provisions for automatic transmission applications. The equivalent radiator but equipped with oil cooler provisions, GM #3018802, was used for base engine cars with THM-400, regardless of whether the car had A/C, or not. As I mentioned previously, the 3018802 replaced the 3018803 for SERVICE in June, 1974. Partly as a result of this and partly because the 3018803 is the primary LT-1 radiator used over the 1970-72 period, this is a very difficult-to-find radiator. However, the 3018803 was also used for 1969-72 Corvettes with base engine, 4 speed, and A/C as well as most (but not all) 1969-70 Corvettes with L-46. Neither the 3018802 or 3018803 were used after 1972 and, as far as I can tell, neither had any applications other than the 1969-72 Corvette applications I mentioned.In Appreciation of John HinckleyComment
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Re: 1972 LT-1 with a/c radiator
Joe, I do have the Harrison logo embossed on the upper portion of my right side tank but the bottom of that tank does not have a drain fitting. In fact, I just took a wire brush to remove all paint to ensure a drain fitting hole had not been soldered over, and the tank is smooth brass that has never been repaired. My car was previously owned by J & J Corvette Center in Hudson, IA in the mid 1980's. I spoke with Jim Wagoner who co-owned J & J with his partner John Merrich (now deceased). Jim told me that John liked the car so much that he used it as his personal vehicle for many months. Now I'm wondering if those guys, having access to all kinds of parts, might have swapped out a damaged or leaking original radiator for something they had lying around, or maybe even something out of an entirely different model. Surely, Harrison must have made radiators for more than just corvettes. Do you know of any right side Harrison tanks without a drain fitting? I agree that the few 70-72 corvettes that I've personally seen all have an elbow with a plug installed. That's what initially made me suspect my end tanks are not original. So to install a "correct" radiator I need a right side tank without cooler fittings, but with a drain, right? Also, I think I would need a MK9 broadcast tag as well, right?Comment
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Re: 1972 LT-1 with a/c radiator
Michael-------
Harrison made radiators for ALL GM cars and trucks. I've not seen a Corvette radiator without a drain but there may have been some. Or, it could be that some SERVICE radiators were made without a drain. In that case, one has to remove the lower radiator hose in order to drain the radiator. In my opinion, you need a right side tank without cooler fittings and with a drain.
My recollection is that MK9 was the broadcast code for the 3018803 radiator. I don't know that all these radiators had this tag on them, though.In Appreciation of John HinckleyComment
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Re: 1972 LT-1 with a/c radiator
My 71 w/AC has what looks more like a plug than a fitting. You may want to look closely, as it really doesn't stick out much on my car.Vice-Chairman (West), Michigan Chapter NCRS
71 "deer modified" coupe
72 5-Star Bowtie / Duntov coupe. https://www.flickr.com/photos/124695...57649252735124
2008 coupe
Available stickers: Engine suffix code, exhaust tips & mufflers, shocks, AIR diverter valve broadcast code.Comment
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Re: 1972 LT-1 with a/c radiator
Don't worry about the drain fitting. A competent radiator shop (And, yes I know those are getting harder and harder to find.) can add that drain fitting if they can procure it. The kind of shop I am familiar with probably has a fitting like that laying around. I know of such a near by to me shop, and if you can get the proper passenger side end tank and all you need is that fitting, let me know and I will go pester them to look in the dingy recesses of their grimy shop. They are a bunch of odd ducks over there, and I generally avoid them unless absolutely necessary.
Last time I was there they identified the application of the radiator I was carrying as I walked up their driveway. It was like the employees were playing a game of "identify the radiator." I suspect the loser had to buy the next twelve-pack. That is the kind of place you just might find your end tanks as well.TerryComment
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Re: 1972 LT-1 with a/c radiator
My 1970 LT1 (obviously no AC) has a right angle fitting that once had a hex plug in the fitting. I am pretty sure I have seen the same right angle fitting in 1970-72 large motor applications as well.
If all the copper/brass radiators don't have that right angle fitting (and I thought they all did) maybe it is something we should identify for the next TIM&JG revision. I believe we have already identified that the material of the hex plug matches the material of the radiator.TerryComment
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Vice-Chairman (West), Michigan Chapter NCRS
71 "deer modified" coupe
72 5-Star Bowtie / Duntov coupe. https://www.flickr.com/photos/124695...57649252735124
2008 coupe
Available stickers: Engine suffix code, exhaust tips & mufflers, shocks, AIR diverter valve broadcast code.Comment
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Re: 1972 LT-1 with a/c radiator
Thank you everyone for responding to my questions.
I think I'm going to take Terry's advice and quit worrying about this. I've decided to reinstall the radiator "as is" and concentrate on "bigger fish to fry". Perhaps at some point I'll have the end tank modified, unless I run across an original in the mean time.
I've got a rusted out 1972, base engine, automatic, parts car that has served as my "Bubba the mechanic learner car" for the past year. I compared the radiator out of that car to the one from my LT-1 and there were only three minor differences that I could detect. The dimensions appeared to be exactly the same. The first obvious difference was the transmission cooler line fittings. Secondly, no drain plug in my LT-1 radiator. Third, the overflow tube attached to the filler neck was at a slightly different angle.
I'm attaching some pictures.
Lastly, to anyone who might want to attend the National in Denver next July. The Crowne Plaza Airport in Denver is now accepting reservations. The website still shows "No Available Rooms", but if you call the 1-800 number they will book a reservation.
Thanks again.
P.S. Screw the pictures. I'm tired of trying to figure out how to post them.
Mike B.Comment
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Re: 1972 LT-1 with a/c radiator
Mike-----
I thought you indicated that the radiator you have in the 1972 LT-1 has the transmission oil cooler provisions? The radiator in the 71 with automatic trans should have the same fittings. So, the radiators should be the same.In Appreciation of John HinckleyComment
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Re: 1972 LT-1 with a/c radiator
Hi Joe,
Sorry for the confusion. The tank in my LT-1 does NOT have automatic transmission cooler line fittings. However, neither does it have the drain fitting at the bottom of the right side tank. When I first noticed that the tank had been re-cored I examined the side tanks more closely, and discovered the missing drain fitting. Then looking in catalogs and parts reference books, they all indicated the correct radiator for my car also fit a car with an automatic transmission and/or air conditioning leading me to believe that GM installed the automatic trans radiators (3018802) in the 72 LT-1's that were optioned with air conditioning. You clarified things for me when you posted that the 3018803 radiator was the correct one but had been discontinued, with the 3018802 as it's service replacement. That's why all the catalogs and parts books now call for a 3018802.
Thanks.
P.S. I finally figured out how to post those photos.Comment
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Re: 1972 LT-1 with a/c radiator
Michael,
The first three photos are of a non-OEM radiator core, and I suspect the end tanks in those photos are of similar provenance. The last photo is an OEM core. I suspect that end tank is OEM also, btu I can't see enough of it to be absolutely sure. The two holes, one square and one rectangular in the top bar of the core in the last photo is typical of OEM. The proportions of the top bar are also typical of OEM. On the end tank the fluid drain tube is angled as expected for an OEM end tank also.TerryComment
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Re: 1972 LT-1 with a/c radiator
Terry,
When I saw the square and rectangle were missing from the LT-1 core I knew immediately it had been re-cored, or was an altogether wrong tank. That's when I examined my side tanks closer and discovered the missing drain fitting. The very last photo is of the tank out of my 71 parts car and is an original tank for an auto transmission car. I included that photo to show the different angle the overflow tube exits the filler neck.
MikeComment
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