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Old 09-02-2019, 03:41 PM   #1
parb
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Thermostat?

Hi all,

I've been out running my Jimmy all weekend. Its literally the first weekend I've been driving it since the restoration completed besides shake down drives. Now that I'm driving longer distances I noticed that the temp gauge is going to within 10% of the red line.
I don't remember what thermostat I have in it but before I do anything I'm going to measure the temperature at the thermostat with an IR thermometer to make sure it's not just the sensor.

However, in case I need to replace the thermostat what is recommended for a 72 350? I have only new exhaust and an electric carb on it, other than that it's bone stock. I won't drive in the winter and I'd say that my typical weather is in the 70-95 degrees. I've read that some people use 165 degree thermostats in this weather, is that what is recommended?

Lots of suggestions on the internet, looking for some insights. I care mostly about making the engine last so durability is my chief concern.
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Old 09-02-2019, 03:54 PM   #2
DeadheadNM
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Re: Thermostat?

The aftermarket sending units are notorious for being off. Folks say those from Lectric Limited work and that has been my personal experience. Let us know what the temp gun reads.
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Old 09-02-2019, 07:14 PM   #3
MySons68C20
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Re: Thermostat?

I have a 195 deg stat in mine and it reads right up to the edge of the hot zone.
I'm going to replace it with a 180 deg and expect it will read in the middle of the range.
I have read that anything less than 180 deg will cause an increase in engine wear.
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Old 09-02-2019, 08:56 PM   #4
psuedopimp
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Re: Thermostat?

I have a stock 307. 195 degree thermostat at it reads right up to the hot line or a tad before it.

I read somewhere that the 195 degree thermostats was the reason they could bump the oil change intervals from 3k to 5k miles. Saved on engine wear also.
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Old 09-02-2019, 09:17 PM   #5
parb
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Re: Thermostat?

I think I had air in the system. I added a bit of more antifreeze, and while it burped up a little bit more than my overflow container could handle (just a few drops really) it seemed to work. I've now been running the engine for a while and it seems to have done the trick.

Drove it on a mix of surface streets and highway just to be sure and half an hour later the temp gauge has solidly stayed at the mid point. It wasn't even that much anti freeze that I added but it seems to have cured the problem.

The IR temp reader reads 185 -190 going into the radiator (on a metal surface) and about 140-150 on the hose returning coolant to the engine. This is with an engine that is running and has been at operating temperature for a while.

I'm sure I have a 180 thermostat due to these readings. All seems well.

Last edited by parb; 09-03-2019 at 12:48 AM.
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