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Topic: Radiator Leak?

in Forum: C3 Cooling and Heating Systems


Radiator Leak?

Posted: 4/8/16 11:34pm Message 1 of 10
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Vancouver, WA - USA
Joined: 8/25/2005
Posts: 869
Vette(s): 1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
Twice now, I've caught my car dripping coolant at the driver's side bottom corner of the rad - once back in Feb when I just started it and let it run long enough for the thermostat to open and then again today when I took it on a 10 mile drive.  It did not do this the one or two times in between that I drove it.  It does not drip a whole lot and stops after it cools down.  It's dripping off the bottom radiator support.  Am I for sure looking at a radiator leak?  Or could it be something else?  It doesn't seem like there's much else around there that it could be.  Can't see anything from underneath or opening the hood.  If it is a rad leak I think the shroud is covering it  



 

1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
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Re: Radiator Leak?

Posted: 4/9/16 5:34am Message 2 of 10
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Scottsdale, AZ - USA
Joined: 5/23/2007
Posts: 617
Vette(s): 1981 Corvette Two-Tone Claret color, 4 spd, C7 Vert
Sorry Dave, besides trying some "stop leak" you know the eventual cure will be a trip to the radiator shop!  Smile


      Only 34 years together

Re: Radiator Leak?

Posted: 4/9/16 12:57pm Message 3 of 10
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Gig Harbor, WA - USA
Joined: 10/2/2014
Posts: 405
Vette(s): 1973 L82 4 Speed Coupe - Very original, well documented driver/survivor. 2016 Bend Regional NCRS Top Flight.
Dave - unless you have a leak at one of the hose connections you're probably looking at a radiator leak. The system usually builds the greatest amount of pressure when hot just after you shut it off, that when most small leaks occur. 

The best way to look for a leak is to find a radiator pressure tester that attaches in place of your radiator cap. They are getting harder to find and it will probably end up with the trip to the radiator shop as Johnu mentions. If you can find someone to test it, have them pressure test your cap at the same time.

Good luck !!



John Sigmund
valkman57@sbcglobal.net
NCRS Member 61302
NW NCRS Chapter Member



Duct tape is the new Black !!

Re: Radiator Leak?

Posted: 4/9/16 6:24pm Message 4 of 10
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Overland Park, KS - USA
Joined: 7/9/2003
Posts: 914
Vette(s): 1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day. 2023 Accelerate Yellow HTC Stingray
Check the joint where the upper radiator hose nipple fits into the tank. Mine had to be repaired several different times because it would crack the joint. The radiator hose is just cantilevered off of it and has no support which puts a lot of stress on that solder joint.  IIRC, some GM models had a support bracket for the upper hose.

Bar's stop leak is the best that I have found and not have small leaks reoccur.


1973 L-82 4 spd

Re: Radiator Leak?

Posted: 4/10/16 12:28am Message 5 of 10
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Vancouver, WA - USA
Joined: 8/25/2005
Posts: 869
Vette(s): 1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
Thanks for the input, guys.  Yep, I know (and knew) that it's almost assuredly a radiator problem.  So here's my radiator story:  When I bought the car 15 years ago (this July) it had a small radiator leak.  I had just bought the car, was getting married in a few weeks, and was pretty much broke.  It was the original one then so I had a shop look at it but they said it was too far gone.  So in went an Autozone rad and all was well until 3-4 years ago when I had another leak.  Somehow, I found my receipt from 11 years prior and since it was a lifetime warranty AZ honored it and replaced it for free.  Sounds like their quality control has gone down since this one only lasted 3 or 4 years and the first one lasted 11 or 12.  So trying to decide what to do - Barr's stop leak, new AZ rad (maybe they'll give me another new one, who knows) or get the current AZ rad fixed.  I'd like to get a good aluminum rad, but not sure a new DeWitt is in the cards right now.  Both AZ rads have cooled the car well, even after I rebuilt and bumped up compression I've never once had any concerns with overheating.  

I'm considering trying some stop leak, but that kind of thing always makes me a little nervous.  I don't care if it messes up the rad, but don't want any problems somewhere else, like in a water jacket or the heater core.  Thoughts?  




 

1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

Re: Radiator Leak?

Posted: 4/10/16 4:44am Message 6 of 10
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Bellingham, MA - USA
Joined: 6/23/2014
Posts: 175
Vette(s): 1980 loaded red on red. 68,000 original miles. Second owner. Well documented with all original paperwork. NCRS Founders Award 9/27/14. NCRS Top Flight 10/12/14.
I put a Champion three row in mine for $220 with cap. I Bought it on line from radiators for less.com if I remember correctly. Very satisfied with it


Re: Radiator Leak?

Posted: 4/10/16 7:07am Message 7 of 10
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Overland Park, KS - USA
Joined: 7/9/2003
Posts: 914
Vette(s): 1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day. 2023 Accelerate Yellow HTC Stingray
 Do you know where the failure was in the previous radiators?


1973 L-82 4 spd

Re: Radiator Leak?

Posted: 4/10/16 9:00pm Message 8 of 10
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Vancouver, WA - USA
Joined: 8/25/2005
Posts: 869
Vette(s): 1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
Man, I'm trying to remember where the leak was on the one that Autozone replaced.  I remember it was very obvious where it was leaking - I was prepared to put up an argument if they tried to say it came from mechanical damage.  But they didn't even really look at it.  I think it may have been leaking on one of the side tanks near the bottom, probably along the solder joint there.  



 

1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

Re: Radiator Leak?

Posted: 4/11/16 2:08pm Message 9 of 10
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Bellingham, MA - USA
Joined: 6/23/2014
Posts: 175
Vette(s): 1980 loaded red on red. 68,000 original miles. Second owner. Well documented with all original paperwork. NCRS Founders Award 9/27/14. NCRS Top Flight 10/12/14.
I'm bad! forgot to mention it was ALUMINUM radiator.


Re: Radiator Leak?

Posted: 4/11/16 5:11pm Message 10 of 10
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Overland Park, KS - USA
Joined: 7/9/2003
Posts: 914
Vette(s): 1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day. 2023 Accelerate Yellow HTC Stingray


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|UPDATED|4/11/2016 5:11:12 PM (AZT)|/UPDATED|



1973 L-82 4 spd

in Forum: C3 Cooling and Heating Systems


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