1966 - thermostat Question

[Rob M.]

I'm getting ready to replace the radiator, hoses, clamps, etc. on my '66 327/300 and I wanted to know what the pro's and con's are regarding a 160 degree thermostat vs. a 180 degree. I know it came with a 180, but I don't plan on having it judged anytime soon. In the meantime, I don't drive it very hard and I live in Southern CA. The 160 was recommended by a mechanic in the local corvette club. I appreciate your comments.

[Duke W.]

Re: 1966 - thermostat Question

Oh, let's see. How about blowby gas dilution of the oil because the crankcase is cool enough to let it condense and not boil out the blowby that condenses during warm-up.

How about less power and poorer fuel economy because the cooling system is removing more of the fuel's thermal energy than is necessary. Chrevrolet Product Performance has been telling us for 30 years that higher jacket temperatures result in more power at the brake. Read any 30 year old Chevrolet Power Manual, if you don't believe it. NASCAR teams don't take tape of the grille opening until the temp goes over 230.

A primary reason why pre war and some early post war cars had 160 stats is because it reduced the boil out rate for alcohol antifreezes, but with ethylene glycol and 13-15 psi caps, the engine can be run hotter. Higher operating temps are beneficial. The only downside is possibly shorter hose life, but modern materials are much better than 30 years ago. That's one reason why modern engines are set up to run from about 190-230.

160 Thermostats should have disappeared in the fifties, but some myths just won't die.

Duke

[Joe L.]

Re: 1966 - thermostat Question

Rob------

I used to think that going to a 160 degree thermostat was a good idea. However, I no longer do. I think that a 170 or 180 degree is a better choice. Slightly higher operating temperature can make a slight improvement in engine operating efficiency. However, the big reason lies elsewhere:

Keep in mind that a thermostat only controls the engines MINIMUM operating temperature after the thermostat's full open temp is reached. The ACTUAL temperature that the engine operates at is controlled by a variety of other factors which are far more important (and, "unchangeable") than the thermostat installed. Most of the time, the temperature that engine is operating at is above the thermostat's full open temp. So, when this is the case, the thermostat is irrelevent.

By using a 170 or 180 degree thermostat, you can keep the temperature that the engine ACTUALLY operates at much more consistent. Since 180 is about the temperature that the engine will ACTUALLY operate most of the time, especially in a relatively warm ambient environment like southern California, I think that a 180 is a good choice. A 170 is ok, though.

[Rob M.]

Thanks Duke and Joe!! *NM*