Overflow tank
Thread Starter
Pro
Joined: Sep 2002
Posts: 624
Likes: 1
From: Melbourne, Fla. 6 months- New Middletown, Ohio 6 months
Overflow tank
I just bought a 71 SB vert with AC and found that it did not have a overflow tank. Had a 70 back in the early 70's but do not remember if it had a overflow or not. Is this due to the fact that with AC there is not much room left under the hood. I would like to install some type of overflow tank, especially with AC in Florida.
I am thinking that I may have to go with one of the small cylinder types that the street rods use and install it next to the radiator in front of the compressor. Would appreciate suggestions if any of you have installed after market tanks.
Did a search and found a similiar comment from a guy in New Zealand I believe on a 69 but nothing for sure on a 71.
Thanks, Bill
I am thinking that I may have to go with one of the small cylinder types that the street rods use and install it next to the radiator in front of the compressor. Would appreciate suggestions if any of you have installed after market tanks.
Did a search and found a similiar comment from a guy in New Zealand I believe on a 69 but nothing for sure on a 71.
Thanks, Bill
Melting Slicks
Joined: Mar 2005
Posts: 2,094
Likes: 298
From: Midlothian VA
These cars didn't come with overflow tanks.
They could come with expansion tanks though.
Expansion tanks are not an "overflow tank" (like you find on newer cars to capture excaping coolant) but an expansion tank for the radiator. When the radiator on one of these cars indeed overflows you'll see that the coolant simply ends up on the ground beneath the car. Capturing that overflow is the function of todays "overflow tanks".
That said, not all cars got an expansion tank. Your old 70 must have been a base model engine with A/C or an automatic transmission (or an LT1).
70-72 all Vettes got an Aluminum expansion tank (Brass for the LS5 wA/C) except:
LT1's and all Base engine & L46 cars with AC and/or AT
They could come with expansion tanks though.
Expansion tanks are not an "overflow tank" (like you find on newer cars to capture excaping coolant) but an expansion tank for the radiator. When the radiator on one of these cars indeed overflows you'll see that the coolant simply ends up on the ground beneath the car. Capturing that overflow is the function of todays "overflow tanks".
That said, not all cars got an expansion tank. Your old 70 must have been a base model engine with A/C or an automatic transmission (or an LT1).
70-72 all Vettes got an Aluminum expansion tank (Brass for the LS5 wA/C) except:
LT1's and all Base engine & L46 cars with AC and/or AT
Last edited by Hammerhead Fred; Feb 5, 2007 at 08:58 PM.
Pro
Joined: Sep 2006
Posts: 551
Likes: 2
From: Clovis CA
Oh you are correct,big blocks did not get them. I tried to fit a 77 bottle, but it did not look right or fit real well. So I took a aluminum Harrison factory tank, cut off the big lines on the bottom, welded the 3/8 inlet tube from the top to bottom. Welded up the hole on top from cut, gutted a factory metal cap so it fits loose but secure. The original burp line next to the cap still functions as a overflow. Then powder coated it semi gloss black.
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
I just bought a 71 SB vert with AC and found that it did not have a overflow tank. Had a 70 back in the early 70's but do not remember if it had a overflow or not. Is this due to the fact that with AC there is not much room left under the hood. I would like to install some type of overflow tank, especially with AC in Florida.
I am thinking that I may have to go with one of the small cylinder types that the street rods use and install it next to the radiator in front of the compressor. Would appreciate suggestions if any of you have installed after market tanks.
Did a search and found a similiar comment from a guy in New Zealand I believe on a 69 but nothing for sure on a 71.
Thanks, Bill
I am thinking that I may have to go with one of the small cylinder types that the street rods use and install it next to the radiator in front of the compressor. Would appreciate suggestions if any of you have installed after market tanks.
Did a search and found a similiar comment from a guy in New Zealand I believe on a 69 but nothing for sure on a 71.
Thanks, Bill
Does your radiator have tanks on each end and/or a radiator cap or does it have a plate type Harrison radiator with no tanks built into the ends?
Thread Starter
Pro
Joined: Sep 2002
Posts: 624
Likes: 1
From: Melbourne, Fla. 6 months- New Middletown, Ohio 6 months
It is a crossflow radiator with tanks on each end and the Radiator cap on the right side of the radiator.
As assumed earlier, I do have the base engine and AT in the 71. My 70 was a 350/350 4 speed. I am thinking that my 70 may of had a tank like 68RATVT showed. Before the 70 was a 66 327/350 4 speed. I know at least one of the two had the tank. There is no room under either fender on the 71 for a tank unless I can pull the side grill off the passenger side and possibly mount a tank of some sort in there. Have to look at that to see if there is enough room there.
As assumed earlier, I do have the base engine and AT in the 71. My 70 was a 350/350 4 speed. I am thinking that my 70 may of had a tank like 68RATVT showed. Before the 70 was a 66 327/350 4 speed. I know at least one of the two had the tank. There is no room under either fender on the 71 for a tank unless I can pull the side grill off the passenger side and possibly mount a tank of some sort in there. Have to look at that to see if there is enough room there.
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
If you have a radiator with expansion tanks built in then you can install a recovery type radiator cap and use a recovery tank. An expansion tank is not necessary.
I don't have any pics, but a 77 recovery tank should fit in there. It's tight. Perhaps someone can post a good pic of one installed.
Here is a tank to give you an idea.http://forums.corvetteforum.com/show...&postcount=391
I don't have any pics, but a 77 recovery tank should fit in there. It's tight. Perhaps someone can post a good pic of one installed.
Here is a tank to give you an idea.http://forums.corvetteforum.com/show...&postcount=391
Last edited by noonie; Feb 6, 2007 at 03:00 AM.
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Team Owner
Joined: Jun 2000
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From: Southbound
Cruise-In II Veteran
Check the AIM. Some applications had the expansion tank, others did not. You may not need one.
My base engine AT '68 has the big 4-row Harrision radiator and no expansion tank.
My base engine AT '68 has the big 4-row Harrision radiator and no expansion tank.
Safety Car
Joined: Sep 1999
Posts: 4,930
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From: AnyTown NJ
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
The base engine in 71 with AC and or automatic did not have an expansion tank.
Why do you think you need one? I've never had mine spit up antifreeze even on the hottest day w/ac on. If yours is I would look for a cause first rather than try to fit a tank in there.
Why do you think you need one? I've never had mine spit up antifreeze even on the hottest day w/ac on. If yours is I would look for a cause first rather than try to fit a tank in there.
Pro
Joined: Sep 2006
Posts: 551
Likes: 2
From: Clovis CA
I also have the big radiator with side tanks, fan shroud, seals in place and a clutch fan. I'm making sure she never overheats, they are known too. Why not have a recovery tank for extra protection in case of burps?
Safety Car
Joined: Sep 1999
Posts: 4,930
Likes: 11
From: AnyTown NJ
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Well, early BB's were known to overheat.....never was an issue w/sb's so if your cooling system is in good working order this shouldn't be a problem.....cooling systems designed w/an external expansion tank obviously need one, those designed without one don't.
Thread Starter
Pro
Joined: Sep 2002
Posts: 624
Likes: 1
From: Melbourne, Fla. 6 months- New Middletown, Ohio 6 months
My only reason for asking for thoughts on the subject was that I randomly had problems in August in Florida in traffic with my 70 which was a 350 with 11:1 compression. The 71 is 8.5:1 and seems to run pretty cool now. I will not do anything unless I do find a need. I appreciate all the replies.
Bill
Bill
Race Director
Joined: Dec 1999
Posts: 19,610
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From: Forked River NJ
Most drag strip will require you to have an overflow tank, puke tank. I did not have one as mine is a LT1 car. I never used the wipers so for sure did not need the washer tank. I just ran a hose to the washer tank and presto a puke tank. Never have gotten any fluid in it but it passes tech at the strip.