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Offline fastfred

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180 degree thermostat without a fan?
« on: December 16, 2014, 03:31:05 PM »
I used to have a 195 degree thermostat in my 1977 2.3 Pinto motor. I thought it ran a little hot in the summer. Can get warm in NC then!  I installed a 180 degree thermo. which improved things.   Because the fan is set up to run constantly I am thinking of removing it. Should be okay with a 180.  I understand these motors run quite hot but still! Anyone tried this?

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Offline amc49

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Re: 180 degree thermostat without a fan?
« Reply #1 on: December 16, 2014, 08:35:42 PM »
If you are thinking of removing fan totally and just relying on the stat that is a mistake....... ..there WILL be times when engine absolutely needs the fan working. Like at idle and traffic light.

Here's a bit more food for thought. Running temperature is a relative thing. We old people were (at least I was) taught that the engine runs better at 180 than 195, but not so. FYI, all engines run a bit hotter than the stat value, or a pretty close to a solid ten degrees plus over what the stat is rated at, because stat BEGINS to open at that rated temp. It opens further but only as water gets hotter. That makes a 180 stat run engine closer to 190 real world, and a 195 runs closer to 205+. That's important for emissions, HC reduces with more temperature but that's not where I'm going. I have later MPFI cars and all are 195 stat and no way would I consider changing that for lower even though the stats are available to do it. First reason, the PCM looks for the higher temp and going to closed loop is sharply defined by that. Running a lower temp stat can get you much worse gas mileage as the PCM then takes longer to go to closed loop and also richens based on the colder temp. The most important reason though is that the engine will last MUCH longer with the hotter stat if everything else is kept in good shape. Why? The hotter stat puts engine temp closer to 212 boiling and at that point all water that gets into the oil then steams out to be sucked off by the PCV system. That's why you can pull a valve cover off a hotter running engine and find virtually no sludge or varnish on engines with over 150K on them. Do that on a colder stat motor and I guarantee you'll find far more sludge, it is formed by having water in the oil because the water doesn't get burned off. The water is necessary for the chemical reaction that turns oil residues into acids, the acids then form sludge. Modern engines pretty much all run hotter, the 3 zetecs I have do not even turn on electric fan until engine hits 220 degrees to guarantee the water is gone. That of course leaves you less squeeze room in an emergency like blown hose or bad water pump, you will be much closer to head gasket blowing temps and why you have to stay after the engine maintenance to make sure it doesn't happen. Why many later engines in junkyard have blown head gaskets, the norm of human nature, or I'm not fixing squat there. Stupid, as the engines can often run to over 300K now and that running hotter is one big fat reason why. A really good reason to keep that PCV in good working order as well.

Offline fastfred

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Re: 180 degree thermostat without a fan?
« Reply #2 on: December 17, 2014, 10:38:43 AM »
Thanks for the reply.  All you wrote makes sense.  I thought maybe a 180 without a fan would in fact allow the temp. to get to 200 or so.  Maybe I will put the 195 back in after all.

Thanks again.

Offline amc49

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Re: 180 degree thermostat without a fan?
« Reply #3 on: December 17, 2014, 06:45:29 PM »
Stat with no fan is fine while car is moving but go to sitting like in a traffic jam and no air flow to radiator, motor will cook then even with a 160 stat. Gotta have that fan at least once in a while. Modern PCM cars may not turn it on for as long as 30 minutes in weather like now but when it wants it it better have it or melt motor city. Car with a/c another story, they need fan a LOT and common on many models to turn fan on 100% of the time when a/c is turned on. Otherwise a/c condenser heat toasts the radiator and no cooling there.

Offline 65ShelbyClone

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Re: 180 degree thermostat without a fan?
« Reply #4 on: October 24, 2015, 11:31:44 AM »
I will add this:

The rate of heat transfer is dependent on temperature differential. Bigger difference = faster transfer, which means that the radiator actually dissipates more heat energy as coolant temperature rises.

Running without a fan at all is a PITA and I don't recommend it.
'72 Runabout - 2.3T, T5, MegaSquirt-II, 8", 5-lugs, big brakes.
'68 Mustang - Built roller 302, Toploader, 9", etc.