C1 is overheating !!

[Don IZzo]

My 60 with a newly rebuilt motor is overheating.I bought the car as a basket case so I can offer no known history.It is a base motor with the radiator with the goose neck filler and no expansion tank. I Replaced the water pump with a rebuilt unit at time of engine rebuild. My original radiator was sent out and checked for leaks prior to start up as there was evidence of an old repair located just below the top tank. The repair looks like someone removed about 3/4" of the fins and repaired a leak. The car has a 160 degree thermostat. When I built this car my local Corvette supply/repair shop recommended I install a new radiator. They said that the original units were prone to overheating. The temp gauge and sender are working correctly. When I overheat the radiator pukes out coolant through the overflow pipe. DO you guys think that the old repair may have reduced the cooling ability of the radiator? Do you think the repro radiators afford any better cooling than the originals? Or should I look for an aftermarket unit, and are there any that are direct replacement? The car is a great driver that will never be judged.

Don

[Ed Jennings]

Re: C1 is overheating !!

If originality is not a concern there are definately replacements available that will outperform the original. Look up DeWitts website. There is a wealth of info there, as well as some real good prices on Griffin radiators.

[Terry Payton]

Re: C1 is overheating !!

Don-just a comment-had the same problem w/my C1. Replaced everything..be cool all-aluminum radiator/new pump/ 2 new thermostats...turns out after spending all the $$$, the 2 thermostats were simply bad. The third one worked-problem solved. just my two cents.

[John M.]

Re: C1 is overheating !!

Don,
Even if the radiator does not leak, it's cooling ability is probably much less than when it was new. Age causes deposits on the insides of the tubes which can really affect the heat transfer. If you have your original radiator, Dewitt sells a repro core that cannot be distinguished from the original. You just have a local shop put you original top and bottom tanks as well as the mounting strap on the new core. I put up with my original radiator for a quite a while before putting the new core and I wished that the core had been available years before! My 60 now runs cool even in the 100 degree heat of Texas. In the past, I would only take my car out on cool mornings or evenings for fear of the car overheating, but now I can go out and bake my brains in the midday sun without worrying about the car overheating. Now overheating myself is a different matter.......

Regards, John McGraw

[Don IZzo]

Re: C1 is overheating !!

It sounds like most (if not all) of you guys think my old tired radiator must be my problem. I did test the thermostate on top of the stove with a thermometer in one of my wife's best pots (not happy!). The thermostate opened right on or about the 160 degrees and closed back down when I added cold water, so I don't think its a thermostate problem. I guess I will go with a new aluminum unit and put the stock unit away. So...what are your opinions? Dewitt or Griffins? My parts guy at the local Corvette supply shop is leaning me to Dewitts. They do have a great warranty and a reasonable price.

Don

[Bob Simard]

Re: C1 is overheating !!

Is the car running hot or just puking a little fluid? If you fill the radiator to the top, some antifreeze will be expelled when hot since the coolant expands and the space does not. When equilibrium is reached, the cool radiator will have antifreeze up to the bottom of the filler tube (approx.). If it really is overheating, the new aluminum radiators will cause you to lose your heater in cool weather. You can't heat it up with so much cooling going on.

[Duke W.]

Re: C1 is overheating !!

A properly operating themostat will not allow the car to "overcool". When closed or just cracked open, the system circulates most of the water through the heater core.

I would recommend a 180 thermostat with a higher pressure cap. Modern radiators and hoses will withstand that pressure. If you have an original aluminum type radiator and it is clogged up it must be replaced. A brass radiator can either be rebuilt with a thorough rodout or a new core.

Also be sure that your initial timing, centrifugal, and vacuum advance are in spec or otherwise acceptable for your engine and that the engine has the proper fan and if a clutch fan, verify that the clutch is operating properly.

Duke

[Larry E. Howard]

Re: C1 is overheating !!

Don, I went through the same problem with my 57 I started with the original fan blade and no shroud or thermostat. The gauge would peg on a 90+ degree day, but it never did boil over or spit out fluid. Understand though that I am running a 283 bored to 4 inch (302) Dart aluminum heads and total compression of about 10.5 to one. Anyway, I bought a shroud first - no help. then installed a 7 blade flex fan - no help. I then bought an aluminum Griffen radiator, based on a suggestion from another 57 owner. The car still pegs the temp gauge. I think my problem is with the aluminum heads and the thin walls from the bore job. The point I am making is that even after shelling out over $700 bucks, I still have the same problem it just takes a longer time to peg the temp gauge. Some guys say that a rebuilt motor runs hot For a while. I have about 800 miles on mine and no noticeable change. IF you bored yours very much when you rebuilt it. could be the problem. Also don't forget that a blown headgasket, Will also cause overheating and fluid loss.