72 351C starts to overheat at idle
#11
Mike,

I am using a 190 degree thermostat and the engine stays at 190 at idle.  When cruising it will drop down to between 180-185. 

It is possible you have an air pocket as Mike suggested.  My thermostat did not have a bleed hole so when I filled the radiator up I disconnected the heater hose on the manifold.  This will allow air to pass through when initially filling up the radiator.

Mike
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#12
Honestly, I have never seen a thermostat rated at 190 degrees.  Is that something you find on the east coast?  On the west coast we have 160, 180, 195 and if you want OEM Ford the closest to 190 is 192.  Also, if put a thermostat in a pot of water with a thermometer you will find they start opening at the rated value and fully open 10-15 degrees above that.  Why a motor would run at temps below the thermostat rating, I don't know.  That doesn't make any sense.
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#13
(06-23-2019, 04:06 AM)1969_Mach1 Wrote: Honestly, I have never seen a thermostat rated at 190 degrees.  Is that something you find on the east coast?  On the west coast we have 160, 180, 195 and if you want OEM Ford the closest to 190 is 192.  Also, if put a thermostat in a pot of water with a thermometer you will find they start opening at the rated value and fully open 10-15 degrees above that.  Why a motor would run at temps below the thermostat rating, I don't know.  That doesn't make any sense.

Maybe it is 195 degree thermostat...but the car runs at 190 at idle and 185 when driving.  I just got back from a cruise night with the Fairlane.  I get a lot of compliments on the car. Not too many around.

https://www.summitracing.com/parts/mof-rt1139/overview/
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#14
That's the thermostat I use in my F150 with a 5.8L.  It's stamped at 192 which is close to 190.

I'm thinking your Fairlane has a 180 degree thermostat in it.  If it's a 190 degree the minimum possible normal operating temp would be 190 unless it is not working properly.
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#15
(06-23-2019, 12:00 PM)1969_Mach1 Wrote: That's the thermostat I use in my F150 with a 5.8L.  It's stamped at 192 which is close to 190.

I'm thinking your Fairlane has a 180 degree thermostat in it.  If it's a 190 degree the minimum possible normal operating temp would be 190 unless it is not working properly.

I know its not 180 so I would say 190 since that is the max temperature it reaches.
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#16
Maybe double check the temp gauge.  It might be off a little.


Maybe there is some confusion.  Thermostats regulate the minimum normal operating temp not the maximum normal operating temp.  For example, a motor with the 180 degree thermostat should at minimum run at 180 degrees.  In reality with a good cooling system the motor will operate about 5-10 degrees hotter than the thermostat rating.  So if your motor runs at 185 to 190 degrees most of the time, it is behaving like it has a 180 degree thermostat in it.  If not, something is not correct, thermostat not operating correctly or the gauge is a little inaccurate.  My guess is the gauge is a little inaccurate.
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#17
I have a 351c in my 71 Mach1.
If you have the factory restrictor plate that is shown on the first page then you need a thermostat that has a "hat"  on it, as shown here. The hat blocks off water flowing into the block and directs it to the radiator. Most parts stores dont know the difference between the 351c and 351w.

https://www.flowkoolerwaterpumps.com/col...thermostat


Here is a substitute thermostat without the hat but the restrictor plate and thermostat are made so that the bypass is still blocked off.

https://www.flowkoolerwaterpumps.com/col...s-bypass-1

As mentioned, you also need a good water pump and radiator in the system.
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