Thermostat questions and running RPM and temps

JLANEF said:
I guess I didn't understand. I thought at high mph speeds is when the freewheeling fan comes into action and is pushed by the wind and actually starts spinning faster then the motor and pulling even more air through. What does the freewheeling fan do at under 40? Thanks, always good to learn more!
Click to expand...
The fan isn't required when it's cold so it freewheels. When conditions are hot the clutch engages the fan which is driven by the serpentine belt from the engine.
 
  • Like
Reactions: Zorba
JLANEF said:
I guess I didn't understand. I thought at high mph speeds is when the freewheeling fan comes into action and is pushed by the wind and actually starts spinning faster then the motor and pulling even more air through. What does the freewheeling fan do at under 40? Thanks, always good to learn more!
Click to expand...
It is at low speeds when a fan is pulling air through the radiator for cooling. At higher speed it is being forced through the radiator.
 
JLANEF said:
Boogieman, the whole system contains about 2 1/2 gallons. drain it all and then put how much thermocre in? How much? Then flush with how much? Trying to determine how much wastefluid I would have in the end? As a kid back on the farm in Iowa I would flush at least 20 to 30 gallons through my 327 at least!
Click to expand...
Empty system, add one bottle of Thermocure with water to refill system and run it a total of 6-8 hours (however many days it takes) to fully clean the system. Then drain and refill with water and run until it's clear. Refill with 50/50 antifreeze.
 
Hoses
Radiator cap
Thermostat

Oh my...

Everything you're describing is a hose, cap, thermostat issue.

Store driving...rpms up...then down. Stopped. Then back up..then down...then stopped.

Hwy you're holding steady at much higher rpms. The water pump is trying to flow massive amounts of water.

Let's review.
You flushed the cooling system. You claim to have done this many times. Let's assume you know what you're doing there.

Your worst trouble is when the coolant is really flowing...or attempting to....but something is preventing this.

Check overflow tank level when cold.

Go for drive. Get it in hot condition. (Not over heated)
Check overflow level now.

It should be more.

If it's no different then you've got a cap problem.

My gut says by your description you've got a hose issue though. Not collapsing all the way shut but enough to limit the flow.

Just know there is a vacuum effect that can happen by any of the above failing. They all work together. If one isn't playing nice you will create a vacuum effect that can also suck a hose closed but due to a failing thermostat and or a bad cap.

Thermostats and caps are cheap. Replace those immediately and really take a good look at your hoses.
I'd do that before anything else
 
  • Like
Reactions: 5632
Top Bottom
Back