How cool is too cool?

94MustangSC

Registered User
My SC'ed Mustang is running between 150 and 190 degrees on a 65 Degree day. On the freeway, at 70MPH it runs 160 ish. If I am going through stoplights, it'll run 180. Is this too cool? Is affecting performance or longevity running at these temps?
 
Do you trust the gauge?

What thermostat are you running?

IMHO, I'd say 150 is too cool. That could negatively affect proper combustion. And it can't occur if you're running the correct thermostat.

180~210 sounds typical on a properly located and operating gauge. I believe a 195 deg. thermostat is stock for the 3.8l SC'd engines.
 
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Unless you have a chip, then running lower than 176 or so could cause some enrichment and spark pulling.... and adaptive actually doesn't start learning until the car runs steady state at or above 176.

Frit
 
I'm running an aftermarket mechanical gauge. THe probe is located right next the the probe for the computer. It's the stock thermostat for an SC. A couple months back the car fell off the jack, and crushed the radiator and ac condensor. I welded up a new radiator support and installed a new aluminum radiator. I also removed the ac condensor. At the same point the fan got broken, so I installed a Permacool unit in place of the stock fan. I am also running a heat extractor hood, with the vents open. When I pull up to stoplights I can see the heat leaving the vents. The car runs like a raped ape the way things are. Recently I installed a new cam and blower, so my benchmark may be a little off. I also run a Mr. Gasket Thermocap on the radiator. It reads in the 190 degree area, so I know the thermostat is opening, but 190 degree's still isn't very hot. Any thoughts?
 
>so I installed a Permacool unit in place of the stock fan.

Runs full-time or on/off...or...?
 
>The Permacool is switched by the computer. I believe it turns on at temps above 200, or if the AC is turned on.

Which would mean it only runs w/the A/C in your case...right?

Get your hands on an IR thermometer/temperature gun and see what the temps are coming off the engine, out of/@ the thermostat housing.

Again, hard to believe you're seeing as low as 170 deg. on the gauge if the thermostat is right range and operating properly. Have you experimented with blocking off portions of the radiator just to see if that has any effect?

  • If the gauge is correct, you might consider steps to raise the temps.
  • If the system is ok, might be time to find a different coolant monitoring method
  • :)
 
The fan turns on at temps higher than 190, which it will hit if it's idling, but not while it's moving. I can put the cover back on the heat extractor hood, which I'm sure would raise temps. Just want to make sure I'm making the situation better.
 
>The fan turns on at temps higher than 190, which it will hit if it's idling

Ah - sorry, based on your original post, I was incorrectly stuck on 190 being the max you saw at all times.

Seems like you're possibly ok during warmer weather, but below desirable in colder weather. Cap the hood between Halloween and April Fool's Day and you should be good ;)
 
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