195 degree thermostat running at 180?

Aaron Ford · Dec 18, 2011

I wrote a few eeks ago about running a hotter thermostat (195) in my Massey 65 gasser that was originally equipped with a 160. With the 160 the engine temps never exceeded 157 and slobbered and stank when warm. After last nights workout, I noticed a trend. The engine ran cleaner on the governor when demand increased or decreased. The exhaust was much cleaner smelling and looking. There are no black soot fallout marks on the hood. The engine "sounded" better. Smoother. As for fuel usage? I have no idea.

Now the bad. The coolant in the radiator never really came up to temp. The coolant temp would rise until the thermostat opened 190-192, then fall quickly until 175-180 degrees, then begin climbing again. It followed this cycle all night. The load was a 7K car hauler with about 3000 lbs on board. Lots of starts, stops, hills, shutdowns, and alternator load due to full lighting on the tractor and trailer.

A 180 degree thermostat would have been a better choice. With several hours of work to get to it and several more putting it back together, the 195 is gonna stay. It will be interesting to see the effects on the oil.

Aaron

JDseller · Dec 18, 2011

Several reasons you MIGHT be getting a lower reading on your water temperature. The most likely reason is that your gauge is not reading correctly. Not many of them are that accurate. I have a good infrared temperature probe. It is withing +or- 2 degrees. I have found many gauges that are over twenty degrees off from what they are reading. The next common thing causing this is that the thermostat is on the front of the engine and the temperature sender is on the back of the head. So your thermostat could be doing what it is supposed to be doing but the temperature is different front to back on the motor.

buickanddeere · Dec 18, 2011

Is there a coolant bypass around the stat on that engine? It maybe allowing enough cold rad water into the engine to keep the coolant tamps down.
You have verified a fact that many folk can't get through their heads. Somewhere out there the idea was formed. "If too hot and boiling over is bad, then cooler is better".
Hence all the machines that have had the stats tossed in the garbage bin. 160F stats installed or the shutters missing/jammed wide open.
180F is the minimum operating temp. Below 185F cylinder wall wear, ring wear and cylinder wall lube washdown with raw fuel. All problems increase exponentially was the temps drop.
Nobody seems to think about all the rad boil overs from the 1910's into the 1970's with 180F stats. Now vehicles run with 195F stats and the cooling fans don't even switch on until 200F+.
When was the last time a 1980's or later vehicle was seen over heated?

RusselAZ · Dec 18, 2011

You went caroling?

evilboweivel · Dec 18, 2011

put some cardboard in front of that radiator
or a burlap bag completly across the grill
somehow some way limit the amount of air across the radiator and the tractor will run at 190 like you want it to

Ron

Indiana Ken · Dec 18, 2011

(quoted from post at 11:11:06 12/18/11)

....."The coolant in the radiator never really came up to temp. The coolant temp would rise until the thermostat opened 190-192, then fall quickly until 175-180 degrees, then begin climbing again. It followed this cycle all night."....

The above part of your post caught my attention. I believe you meant to reference the temperature of the coolant in the engine, since the thermostat can not control the temperature of the coolant in the radiator. However, the main focus of this reply concerns the cycling between 190-192 to 175-180.

The last thermostat I installed in a 1992 300 cu in Ford 6 did not want to open and I finally shut off the engine. I could hear coolant boiling in the block however the thermostat would not let any water thru to the radiator. After the boiling stopped, I restarted the engine, coolant flowed to radiator and I added the remaining gallon + of coolant. After thinking about what happened I concluded the thermostat sealed well enough to create an air lock at the top of the engine preventing hot coolant from reaching the thermostat.

Now to this fall. I installed a new thermostat in my 1977 wood hauler also a 300 cu in Ford 6 (yeah I like em) however, first, I drilled a 3/32 diameter hole in the mounting flange of the thermostat. The objective was to allow air and coolant to flow past the thermostat allowing it to better sense the coolant temperature. The thermostat works great and there was no air lock - I was able to add all the coolant with out restarting the engine and waiting to top off.

Now to my point, I also believe the bypass hole allows for better temperature regulation since the thermostat cannot accurately sense the coolant temperature when there is no flow. Without flow it may wait (depending how it is located within the engine) until all/most of the coolant in the block is hot after which it opens and remains open. Then it receives a slug of cold coolant from the radiator and quickly closes, waiting to repeat the cycle.

As another poster suggested blocking cold air to the radiator should also be effective.

I would be interested in any comments/observations from others who may also drill the bypass hole when installing thermostats.

Aaron Ford · Dec 18, 2011

Yep!

Aaron

Aaron Ford · Dec 18, 2011

The thermo I used was also for a 300-6. I used an econo 160 degree which I drilled, but this one is the OEM style that already had a vent. I really thought that the coolant temp in the radiator would warm to the point that the temps would stabilize.

Aaron

Aaron Ford · Dec 18, 2011

This should read, "The first thermostat I used was a 160 degree econo. This one is a 195 degree OEM."

Aaron

195 degree thermostat running at 180?

Aaron Ford

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JDseller

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buickanddeere

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RusselAZ

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evilboweivel

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Indiana Ken

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Aaron Ford

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Aaron Ford

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Aaron Ford

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