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Discussion Starter · #1 ·
added 4 row alum rad, 17.5 inch 5 bladed fan. Has a 180 thermo but does not want to run much warmer than 160-170 deg F, particularly when I am moving.

Why would this be? Wouldn't the 180 thermo hold the temp at 180?

Seems like it gets up to 180 after ideling for a long time, then thermo opens, drops. Sometime does this cycle several times.

Would going to 195 help?

Is it reaching thermo temp, opening, then the big rad/fan cooling so fast that temp drops and it keeps cycling like this?

Opinions appreciated. cb
 

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Just some guy
67 coupe, 69 Sportsroof, 86 hatchback
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I would try another 180 thermostat. I've had such bad luck with thermostats over the years that I refuse to buy a cheap one. If your parts counter person says you have a choice of good, better, and best, buy the BEST. Period. I do.
I've had brand new thermostats stick shut, open, and just like yours, open at the wrong temperature.
 

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Before I ever install a new thermostat I always heat up a cup of water to just under the rated temperature and then put the thermostat in it. If it opens then the temperature setting is off. I keep heating the water and inserting the thermostat until I find its opening temperature. If that temperature is acceptable I install it, if not I get another one.

Also how are you measuring the temperature? Are you sure you are getting a correct reading?

John Harvey
 

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Yeah, sounds like you are either in really cold country, or your thermostat is defective. Remember that the thermostat opens slowly and closes slowly, so there is no instant opening and closing. It starts to open at around 180, and is fully open at around 190. Around 190-200 is where these old engines run their best. Keep a 180 degree thermostat in there.
 

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added 4 row alum rad,
Are you sure ?
Most brass rads are 4 row in the HD versions and aluminum rads are usually 2 rows of 1" tube .
A 195 degree thermostat would be fine . I would suggest the Robertshaw# 330-195 balanced
version or the same is also avail from Moroso and Mr Gasket .
 

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Discussion Starter · #7 ·
OfnaJoe said:
Really 4-row alum.?
....oops: stand corrected: THREE row alum. rad.

Was considering a 2 row but wanted to engineer in lots of cooling cpacity while I was at it, and for adding A/C later. Live in Atlanta and a lot of stop and go traffic, all the time.

Did not check the thermo before i put it in with the tric of putting it in water and bringing it to a boil

...and bought the cheap one 9$3.99 from Autozone)

was checking with a new temp gauge installed AND an infra red thermometer.

believe it is time to pull the thermo and check it.

Thanks all. cb

ps; live 18 miles fm Mustangs Unlimited, which is very convenient. c
 

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I've had good luck with the high flow thermostats at the local parts store. The opening is much larger, in fact the opening is the entire diameter of the thermostat. It looks like this:


Where did you find a 3 row aluminum? It either has thin rows or is about 4" thick ;)
 

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I think I run too cool as well. How do you measure the temperature your engine is running at?

In winter w/o A/C on the temp guage doesn't even get above 25%. In summer, with a/c on in Florida, I'm at 75% in stop and go traffic. That seems a bit hot - I'd love to know how measure the temp.

Thanks
 

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Don't use the temperature gauge as an indication of whether you're running at a correct engine coolant temperature. The gauge is best used to determine whether you're running at an anomalous temperature from "normal". I can easily change the gauge reading to whatever you desire electrically and by not adding or deleting anything that Ford provided.

How to measure the true temperature? Use a laser-guided infrared sensor, aimed right at the thermostat housing. Almost every decent auto shop has one.
 

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Discussion Starter · #11 ·
the rad is 4 inches thick. Got from Mustangs unlimited for (ouch) $400.

HAVE been using laser guided infra red thermometer. They are great tools for HVAC, vehicles, etc. cb
 
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