'60 overheat solved, thx NCRS

[don whitehead]

Well folks, looks like my overheat on the 1960 270 hp was a combination of things and looks like we've solved them with everyones help.
1 bad fan clutch,even new ones don't work sometimes
2 bad rad cap, not holding pressure, only 7 lbs
3 timing off
4 heat gauge 10 degrees higher than actual
5 tight new engine
6 anti-freeze mix ratio
7 bad heat riser(yes even NOS don't work sometimes)

The last problem was diagnosed/solved when the gas perc'd in the carbs. The heat riser was sticking. Special thanks to Bob Kunz for that one.
Thanks all! Hopefully we finally got it.
Don

[Michael W.]

Don't understand #6-

how could the ratio between water and antifreeze contribute to overheating?

[Michael W.]

Don't understand #6-

how could the ratio between water and antifreeze contribute to overheating?

[Joe C.]

Re: Don't understand #6-

Mike:

The boiling point of the coolant is dependent on the antifreeze/water mix ratio. A 50:50 mix will raise the bp to somewhere around 240 degrees @ atmospheric pressure. Optimal ratio is 70:30, where the bp climbs to about 265 degrees @ atmospheric. Check the label on the antifreeze bottle for exact temperatures.

Joe

[Joe C.]

Re: Don't understand #6-

Mike:

The boiling point of the coolant is dependent on the antifreeze/water mix ratio. A 50:50 mix will raise the bp to somewhere around 240 degrees @ atmospheric pressure. Optimal ratio is 70:30, where the bp climbs to about 265 degrees @ atmospheric. Check the label on the antifreeze bottle for exact temperatures.

Joe

[Joe C.]

ADDENDUM

The boiling points are WITH a 15 pound cap, NOT atmospheric.

50:50----265 degrees
70:30----276 degrees

[Joe C.]

ADDENDUM

The boiling points are WITH a 15 pound cap, NOT atmospheric.

50:50----265 degrees
70:30----276 degrees

[Duke W.]

Re: Don't understand #6-

Ethylene glycol has less heat capacity than water, so a temporary crutch to running hot is reducing the antifreeze concentration.

GM designs its cooling systems to have adequate cooling capacity under most driving conditions with a 50/50 water/glycol mix.

Duke

[Duke W.]

Re: Don't understand #6-

Ethylene glycol has less heat capacity than water, so a temporary crutch to running hot is reducing the antifreeze concentration.

GM designs its cooling systems to have adequate cooling capacity under most driving conditions with a 50/50 water/glycol mix.

Duke

[Bernard M.]

Understand 6 Confused about 2

Shouldn't a 1960 only hold 7 pounds pressure? I thought they came with a 7 pound cap.

[Bernard M.]

Understand 6 Confused about 2

Shouldn't a 1960 only hold 7 pounds pressure? I thought they came with a 7 pound cap.

[John H.]

Re: Understand 6 Confused about 2

Yup, 7# is correct - a 15# cap won't make it run any cooler, but it will increase the temperature at which it boils, overcomes the cap seal pressure, and pukes out of the overflow on the ground.

[John H.]

Re: Understand 6 Confused about 2

Yup, 7# is correct - a 15# cap won't make it run any cooler, but it will increase the temperature at which it boils, overcomes the cap seal pressure, and pukes out of the overflow on the ground.

[Michael W.]

Re: ADDENDUM

Yes,

You're right that the boiling points/freezing points are altered with the use of antifreeze.

The question was why does the engine run hotter/ cooler by varying the mixture? Duke suggests that antifreeze "absorbs' less heat, which I accept, but how effective is this in the real world?

[Michael W.]

Re: ADDENDUM

Yes,

You're right that the boiling points/freezing points are altered with the use of antifreeze.

The question was why does the engine run hotter/ cooler by varying the mixture? Duke suggests that antifreeze "absorbs' less heat, which I accept, but how effective is this in the real world?