Cooling system help...
Thread Starter
Pro
Joined: Jul 2005
Posts: 606
Likes: 0
From: Prattville AL
Cooling system help...
Well... I have been on a pursuit to resolve my overheating problem.... or indicating overheat condition or... airflow problem... or... well, you get the idea. Alright.. I am about to take some holiday vacation time and plan on working on the Vette to resolve my problems... so I have the seals to put on either side of the radiator support and across the bottom to seal up the gaps... question is this... any recommendations on how to seal up the gap across the top btwn the radiator and the shroud?
Thanks
Scott
Thanks
Scott
Race Director
Joined: Jan 2002
Posts: 15,342
Likes: 2,717
From: Close to DC
C2 of the Year Finalist - Modified 2020
Scott, What year, model, engine are we dealing with? Is the overheatring occuring at speed or low speed or idle? On another approach what is the condition of your ignition system, inparticular the distributor vacuum advance. Is it working....disconnect the line to the vacuum can and see it your engine idle changes, if it does it means the can is working. I'm sure other her will advise and suggest. If your car is a midyear you can get the top seal (it clips on) from Long Island Corvette supply. Good luck! 
Thread Starter
Pro
Joined: Jul 2005
Posts: 606
Likes: 0
From: Prattville AL
Thanks for the reply... the car is a '62 with a FastBurn 385 crate motor with a BG Speed Demon carb.... it is perfectly tuned wrt ignition, timing and advance (thanks again Lars)... the gauge indicates 220+ (pegged high)... I have changed nearly everything to include a new aluminum radiator, new sender (twice), new thermostat (balanced high flow 180), checked the gauge with a modern one which indicated the same... I have IR gunned the motor and it looks good all the way around... nothing suspiciously high... does not puke fluid... seems to run near normal temp at speed... it is missing the lower shroud which I have now to install next week.. has an electric pull fan on the backside of the radiator as well as a flex fan on the motor... my next step was to try to seal up the gaps around the radiator btwn the radiator support and the radiator... we'll see how that helps... my only concern was the gap btwn the radiator and the top shroud which is about an inch and half....
Scott
Scott
Burning Brakes
Joined: Oct 2006
Posts: 797
Likes: 11
Have you tried water wetter yet ? Also some electric fans are designed to go on the front or back of the radiator and you have to switch the blades. Check the rotation and pitch of the blades.
Last edited by Injected Stingray; Dec 10, 2006 at 10:03 PM.
Melting Slicks
Joined: Sep 2004
Posts: 2,917
Likes: 13
From: NE Illinois IL
I'm not sure I get this--when you IR the upper radiator hose the temp is ok, but from both the factory and an aftermarket gauge the temp is at 220?
Honestly, it sounds like you are doing everything right. With everything you've replaced there aren't many variables left. Do you have vacuum advance, and if so, are you sure it is coming in with the vaccuum your engine produces at idle?
Also, have you performed a cooling system pressure test?
Honestly, it sounds like you are doing everything right. With everything you've replaced there aren't many variables left. Do you have vacuum advance, and if so, are you sure it is coming in with the vaccuum your engine produces at idle?
Also, have you performed a cooling system pressure test?
Le Mans Master
Joined: Nov 2000
Posts: 7,246
Likes: 21
From: Going too fast over the hill. Iowa
I don't know where you are or what the altitude or ambient temp is, but since your profile says you're a naval aviator - I'll guess near sea level and a moderate climate. Higher altitude can require carb changes, and the Gulf coast or socal can make city traffic hot.
IMO since it runs at 180 on the highway, I will assume the cooling system has capacity to cool the engine, but I found that a stock rad couldn't handle my car at 80-85 going up mountains with A-C running - and neither could an aftermarket aluminum rad with 1inch tubes - so I now have a Griffin with 1.25inch tubes that can handle it. With that big engine, you may need a rad upgrade, but don't decide that until you seal the shroud. BTW you can test the effect of the air gap at the top of the rad by sealing it with duct tape/cardboard.
Does the engine temp stay at 180F if you let the car idle in the driveway with the pull fan running and the hood up? If so, sealing the shroud may fix an air flow problem with the hood down. If not, I suspect that either the pump or the rad lacks capacity. I assume the lower rad hose is good and not collapsing under pump suction and that you have stock pulleys driving the pump at the correct speed.
IMO since it runs at 180 on the highway, I will assume the cooling system has capacity to cool the engine, but I found that a stock rad couldn't handle my car at 80-85 going up mountains with A-C running - and neither could an aftermarket aluminum rad with 1inch tubes - so I now have a Griffin with 1.25inch tubes that can handle it. With that big engine, you may need a rad upgrade, but don't decide that until you seal the shroud. BTW you can test the effect of the air gap at the top of the rad by sealing it with duct tape/cardboard.
Does the engine temp stay at 180F if you let the car idle in the driveway with the pull fan running and the hood up? If so, sealing the shroud may fix an air flow problem with the hood down. If not, I suspect that either the pump or the rad lacks capacity. I assume the lower rad hose is good and not collapsing under pump suction and that you have stock pulleys driving the pump at the correct speed.
Last edited by magicv8; Dec 11, 2006 at 11:06 AM.
Tech Contributor
Joined: May 2005
Posts: 15,576
Likes: 118
From: Conroe Texas
For reference, here is Orion's previous thread on his cooling system problems. This will get us all on the same page with regard to the problems/solution attempts
http://forums.corvetteforum.com/show....php?t=1557994
http://forums.corvetteforum.com/show....php?t=1557994
Le Mans Master
Joined: Nov 2000
Posts: 7,246
Likes: 21
From: Going too fast over the hill. Iowa
Thanks 62jeff
Orion: I sealed my shroud gaps with automotive self stick .5x.75 weatherstrip from a local Farm&Fleet store. After 2 years the weatherstrip is shrinking from the heat, so I went junkyard shopping and got some wide back door weatherstrip from a Chevy suv. I will replace the self stick with the edge grip factory weatherstrip this winter. As for the gaps at the top, I built that up with fiberglass (my BB shroud is plastic) but the suv weatherstrip is over an inch wide, and might work for you.
Orion: I sealed my shroud gaps with automotive self stick .5x.75 weatherstrip from a local Farm&Fleet store. After 2 years the weatherstrip is shrinking from the heat, so I went junkyard shopping and got some wide back door weatherstrip from a Chevy suv. I will replace the self stick with the edge grip factory weatherstrip this winter. As for the gaps at the top, I built that up with fiberglass (my BB shroud is plastic) but the suv weatherstrip is over an inch wide, and might work for you.
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Instructor
Joined: Jun 2006
Posts: 199
Likes: 1
From: Atascadero California
I had the same problem with my 65 vert,finally put an aluminum rad in.It still ran 200 around town and 180 on the freeway with a 160 stat.
Today i put a seven blade flex fan on her and that solved my problems.
160 on the freeeway and 180-190 in town.
yello65
Today i put a seven blade flex fan on her and that solved my problems.
160 on the freeeway and 180-190 in town.
yello65