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Discussion Starter · #1 ·
For those of you who drive long distances on the freeway, how hot does your car run? While driving down the freeway today (40 miles) my car ran about 3/4 up the gauge for about half of the drive at 60-70 mph. I have a new radiator, 4 blade fan with no fan clutch, fan shroud is installed and I've recently flushed the engine of all rust/debris and pulled the block drains and flushed all that out. 68 with a 289
 

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197-199 degrees or 203-205 with the a/c on or about a third of the way up the temp gauge.
 

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The factory gauge can be meaningless. Never very accurate, they are now 50 years old. If you have an aftermarket replacement sender, you're really in trouble.

So, you need to find out what the temperature really is. These cars ran about 200°F summer, winter, city, highway when they were new.
 

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I've noticed different temperature senders can show a slightly different reading. But it's no more than the width of the needle. Most gauges will read cooler than yours though.
 

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A/C 3-core radiator, shroud, flex fan - no clutch. Lot's of timing. Pretty steady 200* or so.

Do your fuel gauge and oil pressure gauges also seem to be a little bit on the "high side"?
 

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I run 195 in 100 degree weather with a 195 thermostat. BeCool aluminum radiator and two sucker fans with a 427 Dart Windsor.
 

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How do you (anyone) know what temperature you are running?


IR indicator scanned off the top of the radiator?
 
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How do you (anyone) know what temperature you are running?


IR indicator scanned off the top of the radiator?
Fitech handheld. I had to replace the sender that came with the kit with a good one, but I'm pretty sure its accurate.
 

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My 66 runs 5 miles on 90 degree summer city heat. Read

Thermostat housing 177

Intake manifold just after thermo hosing 186

top hose 186

bottom hose 161

Top tank 176

Bottom edge of tank 150

Collect connection at bottom hose 160

So I mm tempted to change to a aluminum high rise intake manifold and change the thermostat to a 160. But I dont know if the result will be meaning full. Also dont know if the heat is right for the spark plugs.

V8 , long pipe headers 4BBl 2 core all OEM. 8 degrees timing.
 

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67 coupe, 69 Sportsroof, 86 hatchback
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How do you (anyone) know what temperature you are running?
Autometer makes some very high quality temperature gauges. With numbers on the face. Bargain shoppers might install one temporarily to see how actual numbers correlate with the stock gauge. Then the stock gauge readings are a lot more meaningful. Kind of a pain the the butt to accomplish but you get to keep the interior of the car stock and have at least an idea of what's up when looking at the stock gauge.

Same trick is a lot easier to do with an extra oil pressure gauge. I've used one on all my Fords (with stock gauges) just so I know better what the stock oil pressure gauge is telling me.
 
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Discussion Starter · #11 ·
I haven't checked it yet with my temp gun since I've gotten all the new bits installed. I'll do that when I get a chance. I have a thermal camera, so I'll try that too, just didn't think to bring it with me on this highway run. My girl gauge reads empty when there's still about 4 gallons left, but I've chocked that up to the sprectra sender. Oil pressure gauge works, but doesn't do anything right now because the sender is best and I haven't changed it yet.
 

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Like 22GT said, the originals were not accurate, nor were they intended to be. 50 years on, with many hands in the pot, corrosion, ageing wiring, unknown quality of senders and grounding. Increased resistance in the ground path changes the readings. If there were actual numbers on the gauges, the dealerships would have been flooded with vehicles with nothing wrong, other than the owner's perception. Millions upon millions of cars were on the roads with nothing more than a set of warning lights.
 

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My 66 runs 5 miles on 90 degree summer city heat. Read

Thermostat housing 177

Intake manifold just after thermo hosing 186

top hose 186

bottom hose 161

Top tank 176

Bottom edge of tank 150

Collect connection at bottom hose 160

So I mm tempted to change to a aluminum high rise intake manifold and change the thermostat to a 160. But I dont know if the result will be meaning full. Also dont know if the heat is right for the spark plugs.

V8 , long pipe headers 4BBl 2 core all OEM. 8 degrees timing.
I don't see any problems with your temperature readings, why do you feel the need for a 160° thermostat ?

Like 22GT said, the originals were not accurate, nor were they intended to be. 50 years on, with many hands in the pot, corrosion, ageing wiring, unknown quality of senders and grounding. Increased resistance in the ground path changes the readings. If there were actual numbers on the gauges, the dealerships would have been flooded with vehicles with nothing wrong, other than the owner's perception. Millions upon millions of cars were on the roads with nothing more than a set of warning lights.
When I was young I wanted every aftermarket ever made for "precise information", I never ended up spending the money for them. Guess what ? 34 Years later and multiple vehicles with nothing more than factory gauges with never a need for anything more, including my 30 year old Toyota. The one time I had a car overheat from a blown head gasket, I didn't need a fancy gauge to tell me ! Failures are rarely subtle.

If you have a fairly modified engine/cooling system, I could see it for diagnostics, or at least getting a correlation to the factory gauge reading.
 

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67 coupe, 69 Sportsroof, 86 hatchback
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and change the thermostat to a 160. But I dont know if the result will be meaning full. .
The result would be an engine that never gets up to proper operating temperature. In the long therm that would mean a bunch of very ugly black carbon oil sludge buildup inside the engine which you'd probably incorrectly blame on the oil. (It's a tradition) If your thermostat needs changing, change it to a proper factory recommended 195F thermostat. I've had numerous issues with aftermarket thermostats, enough to where I take the trouble to get a Motorcraft brand one. There are many threads here explaining why one should use the correct 195 degree thermostat if you care to search a couple up and read.
 

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How do you (anyone) know what temperature you are running?
I put a 3/8 pipe thread fitting in the hot tank of the radiator. Threaded in a thermocouple that I hooked up to a Fluke meter for trouble shooting.
Also compared that to an Infrared gun. The gun was close (<5 degrees different) if I was aiming at a painted surface.

Answer is that the engine runs 205-210 all the time.
 
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