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Does a rebuilt engine run warm until the break in is finished?

The major factors for heat transfer are the amount of masses to be involved in the transfer, both of the water flow and the airflow, AND the temperature difference between the two, not time. There are of course others less critical like the ability of the coolant to transfer heat, etc.

Excessive water flow concerns only enter the picture when water flows fast enough over/around internal obstructions than it can cavitate even with the normal cap induced static pressure in the system creating hot spots that are difficult to detect, ie likely very rare.
 
What causes the low temperature differential between the top and bottom radiator hoses?

What us considered normal?

Is too great a difference bad?
 
Rather than shooting the upper and lower hoses with the temp gun, try shooting the upper and lower tanks near the hose connections and see what the difference is. Temp guns read some types and colors of surfaces more accurately than others, black, metallic being generally the best.
 
themechanic said:
What causes the low temperature differential between the top and bottom radiator hoses?
Click to expand...
a. Not enough airflow
b. Air Temperature too close to water temp
c. Not enough radiator between the two
d. inadequate heat absorption by the coolant chosen
e. the radiator hoses are possibly over insulated and preventing a realistic measurement on the internal water temp
themechanic said:
What us considered normal?
Click to expand...
a. Whatever allows the engine to operate at the chosen temp
themechanic said:
Is too great a difference bad?
Click to expand...
a. No because, the thermostat chosen will regardless maintain the min temp, it would however indicate the system is over designed and overcapacity, at that moment it is being measured
 
AR67GTX said:
Rather than shooting the upper and lower hoses with the temp gun, try shooting the upper and lower tanks near the hose connections and see what the difference is. Temp guns read some types and colors of surfaces more accurately than others, black, metallic being generally the best.
Click to expand...
Top rank is easy. Bottom tank will require a bit of contortion of the body
 
Is the AC system a new addition ?
 
themechanic said:
No.
Click to expand...
I seen were its a original AC car , I just wondered if the classic air was a new addition ?
One easy test on idle air flow is to place a dollar bill on the grille front.
At operating temp with the fan locked up at low idle that bill should stay in place. If it slips down or falls off you do not have enough air flow.
 
1967coronet said:
I seen were its a original AC car , I just wondered if the classic air was a new addition ?
One easy test on idle air flow is to place a dollar bill on the grille front.
At operating temp with the fan locked up at low idle that bill should stay in place. If it slips down or falls off you do not have enough air flow.
Click to expand...
I had the AC installed in 2012.

A red shop rag sticks to the condenser at idle; hot and cold. You can feel the air blow out from under the hood where it meets the fenders.
 
R413 said:
Yes they run hot, your numbers look good for what you have there.

Also, thanks for all the detailed info. Many never post this stuff so we must guess.

If it's too warm then try a 160 thermostat. It will be fully open 20 degrees cooler.

Also you don't need a 50/50 mix antifreeze, that's -35 protectoion. What is the record winter low where you live? Less antifreeze cools better.
Click to expand...
hits -38c 2-3 times a year here. I had been led to believe 50/50 was good to -45c?
 
themechanic said:
Does anyone know the coolant volume of the engine vs the radiator and hoses?
Click to expand...
The coolant volume circulated is determined by the pump's design, ( impeller diameter, number of impeller "blades or vanes", and impeller RPM). Remember that the velocity of the coolant (the faster the better) is the secret to efficient heat transfer.......in terms of Btu/hr.......second law of thermodynamics applies.......
BOB RENTON
 
RJRENTON said:
The coolant volume circulated is determined by the pump's design, ( impeller diameter, number of impeller "blades or vanes", and impeller RPM). Remember that the velocity of the coolant (the faster the better) is the secret to efficient heat transfer.......in terms of Btu/hr.......second law of thermodynamics applies.......
BOB RENTON
Click to expand...
Is the volume in the block equal to the volume in the radiator at all times?
 
A 440 engine is very close to 2 gal of coolant. Then add what the hoses and radiator hold.
 
j-c-c-62 said:
No and there is no real basis across the board that it need be.
Click to expand...
It matters. Say you have a larger volume in the radiator cooling down than you have hot coolant circulating in the block. If that is the case, it would seem more efficient than the other way round.
 
I never said it did not matter. What matters is whether the system is able to obtain and maintain the temp sought, and equal volume by itself is no guarantee or requirement for achieving that goal.
 
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