Dave Tuten

Hello All,
Having an overheating problem, I think. Just installed newly rebuilt 283 and first time running it for break-in my temp went to 200 quickly with 180 degree therm in (was stuck shut). Replaced thermostat at 180 and after running about 15 minutes temp started climbing and I shut off at around 190. Now, all is in place, water, new 180 therm, fan shroud directing air over motor, radiator cleaned and boiled and new hoses. Question: the hood is off and car is enclosed in garage, door open. Will the hood off cause some of this problem? Also, is there any disadvantages of going with a 160 degree thermostat? Not sure which way to go....hood or 160 thermostat or both.....
Thanks,
Dave T.

65GGvert

If the temp climbs after a 180 thermostat opens, it will climb after a 160 thermostat opens, too. A thermostat doesn't control how hot an engine will run, it opens when the engine has reached it's minimum operating temperature, decided by the operating temp of the thermostat.

gbvette62

The engine is not cooled, by air flowing over the engine. Engine cooling is accomplished by the fluid in the engine, being cooled by the radiator. The purpose of the shroud, is to allow the fan to draw as much air as possible, through the radiator.

Actually, air coming through the radiator, may have an adverse effect on cooling the engine. Once air comes through the radiator, it's been heated.

Having the hood off, isn't going to cause the engine to run hot. If anything, it should run cooler with the hood off. A closed hood will trap hot air, under the hood.

A 160 thermostat, may help, but I don't really think that is where your problem lies.

Is the timing set right, as this will cause an engine to run hot. You may also have air trapped in the system. Do you have a clutch fan, and is it working properly? It's not real common, but it's even possible that there might have been crud in a water passage, that was loosened up by the rebuild, and is now clogging the radiator.

Freshly rebuilt engines, can run a little hot too.

1955 copper

Is the original design and uses 160. originally

56Heap

Nothing wrong with 190 or 200 idling.

ejboyd5

Newly built engines may run a little hotter than usual - nothing to worry about. Don't trust the temperature gauge. If you are concerned get an IR gun to check temperatures at several different places in the cooling system. If it were my engine, I'd take it out on the road and see how it goes. 190-200 after idling for 15 minutes is not abnormal. By the way, you did do the cam/lifter break-in routine, didn't you? Prolonged idle periods with a new engine are not good.

JohnZ

That was in the days of alcohol-based anti-freeze that boiled off at 180*F; with permanent (glycol-based) anti-freeze, 180*F thermostats were used.

JohnZ

You might want to read this article so you better understand how your Corvette cooling system operates, how to diagnose it, and how to dispel the "internet myths" about cooling problems.

http://www.lbfun.com/warehouse/tech_...em/cooling.pdf

Dave Tuten

Thanks John,,,very informative. I'm sure my timing may have a part in the heating problem...thanks again
Dave