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Operating Temperature Range?

BGBronco

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N A S H V I L L E
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Jun 23, 2017
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Loc.
Tennessee
I have a 76 w/ A/T, 302, FiTech (upgraded temp sensor), newer 195 thermostat, original radiator (I think). Mainly use it for in town driving. My operating temp range is 195 - 205 right know but it has spiked to 210 in the past when sitting in traffic.

I'm wondering if this is 'acceptable' or if I need to start trying to dial this back to a more consistent 195. If so, where should I start diagnosing the problem?

Thank you.
 

B RON CO

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Bronco Guru
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Jun 29, 2016
Messages
2,413
Loc.
Statesville, NC
Hi, your engine is not running too hot now, but you may see higher temps in the summer, or on a trail.
First, free and easy is check your timing, including advance. If you don't have a dial on the timing light, at least raise the RPMs and the timing mark should go up under the water pump. That is your mechanical advance. You check the vacuum advance with a vacuum pump.
Or put in a 180* thermostat.
I would imagine an original radiator is nearing the end of it's life.
Good luck
 

Broncobowsher

Total hack
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Jun 4, 2002
Messages
34,835
Completely acceptable. The thermostat is analog, not digital. it will have a lot of variability to it. Mine comes up to about 180 fairly quick, starts to open and slowly creep up to about 190. give it some run time, stop and go traffic, summer day, it will hit 205 and stabilize. Shut it off and let it heat soak and it will spike higher.

Don't forget that the FiTech temp probe is well known for not being accurate.
 

Eoth

Bronco Guru
Joined
Mar 10, 2004
Messages
1,677
Your fine... 220 is suppose to be the upper limit. Generally speaking the engine runs better on the warmer side however higher heat over time will take its toll. I like using a 180 degree thermostat so I have a bigger cushion and its more obvious I have a problem before things overheat.
 

Timmy390

Bronco Guru
Joined
Jan 1, 2011
Messages
5,609
Loc.
Conway, AR
IDK about the FiTech but the standard for factory EFI seems to be right at 210 for all makes. EFI likes a bit more heat.

I run a 195 stat and sit at 210 on a mechanical gauge. On really hot days stuck in traffic I've seen 220 but that could have something to do with the fact I'm running an electric fan so it's kicking on/off. No constant airflow like with a fixed fan.

Keep in mind stat starts to open at their rated temp but will not be fully open till 12-15 degrees above that.

Tim
 

Steve83

Bronco Guru
Joined
Jul 16, 2003
Messages
8,981
Loc.
Memphis, TN, USA, Earth, Milky Way
Read the back of any coolant jug for the correct temperature range. There's no danger until you approach the boiling point of your coolant mixture AT THE CAP'S PRESSURE (which is a higher temperature than the bottle's chart). So ~240°F is generally safe. The higher the temperature, the more fuel-efficiently the engine is running, and the more water & gas will be cooked OUT of the engine oil (which is good).
 
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BGBronco

BGBronco

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Jun 23, 2017
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Loc.
Tennessee
As an update, I just did a 65 mile Interstate drive average about 65 MPH. ~80 degrees and sunny. Small variation here and there but steady at 210. Acceptable?
 

73azbronco

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Bronco Guru
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Nov 11, 2007
Messages
7,796
I use a scanner on my 2013 jeep to read data through the ODB port, one is water temp, the sensor is located last cylinder on left. Anyway, it runs anywhere from 200 fully warmed up when it is really cold, and up to 238 on hill climbs pulling 1500lbs 110 outside air temp AC on. Thats normal, the hi speed fan kicks in at 238 and immediately cools temps to 220. Day to day, 210-220 is what I see as normal.
 
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