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Could there be such a thing as running TOO cold?

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Old 06-17-06, 02:24 PM
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Could there be such a thing as running TOO cold?

just a thought i was having while sitting in traffic. i know cars have nominal operating temps, but with our (or at least my) obsession of keeping underhood temps down i was wondering if it were possible to have the car running below nominal temps.

my car has a vented hood, water wetter added to the coolant, manual fan control, and the more air-flow efficient 99 front end. but i have the stock radiator. what would happen if i were to throw an after market radiator into the mix?

thoughts on this? or am i off my rocker....
Old 06-17-06, 02:33 PM
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For driving without hard acceleration, there is no such thing as too cold. For spirited driving, I like to see coolant temps 190 or higher. The stock ecu may not let your car run at its full potential if coolant temps are under 190.
Old 06-17-06, 03:01 PM
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i was running too cold a while back. I removed the stat and i was dipping into cold start teritory on cruising. ( droping below 70 deg C )

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Old 06-17-06, 04:15 PM
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The main thing to worry about would be oil temps. Oil needs some heat for its lubrication properties to work effectively.
Old 06-17-06, 04:26 PM
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Measure oil temps before water temps. Oil temps matter most.

edit: My Main Man Mahjik already mentioned it.
Old 06-18-06, 08:13 AM
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i hear ya... thanks for the input. i think im gonna replace/upgrade my oil coolers... the rocks and crap out here in VA are wreaking havoc on them (more than a few bent fins).
Old 06-18-06, 08:39 AM
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Adam, I thought 180 was the lower limit?
Old 06-18-06, 09:45 AM
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The stock ecu does not open the double-throttle plates until 176F.
Old 06-18-06, 03:25 PM
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Originally Posted by FDNewbie
Adam, I thought 180 was the lower limit?
On my car I get some high rpm hesitation, at WOT, when the coolant temps are only 180. It doesn't seem to matter how long I have been driving the car. If I let the temps climb to 190, or more, the car runs stronger, and there is no high rpm breakup. I attribute this to ECU, thinking the car isn't fully warm, trying to "protect" the engine.
Old 06-18-06, 03:32 PM
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Old 06-18-06, 07:09 PM
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I thought there was a certain temperature engines needed to run at for optimal performance, mind you, it probably can run below ths temp without damage but I figured it should be held at that "just right" temperature. Its not the magical number for all cars, but im sure its a range.
Old 06-18-06, 07:12 PM
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You thought right. The optimum temp range for the FD is 180 - 220. Or as Adam as mentioned, it may actually be 190 - 220.
Old 06-18-06, 10:16 PM
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Originally Posted by rynberg
The stock ecu does not open the double-throttle plates until 176F.
Double throttle plates? Who has those? lol
Old 06-19-06, 02:47 AM
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yeah dude, you're a little neurotic, the only time when you're going to run too cold is during your warm up period. and id never thought i'd see a thread like this in the third gen section where im supposed to be reading about people overheating thier motors from idling... geesh


and sorry for the thread hijack but im a newb and dont want to start a new thread. what temp do you guys with the manual fan switch mod flip it on? and when is the terminally highest temperature you can operate at, as in as high as you possibly can without damaging the motor
Old 06-19-06, 03:19 AM
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Originally Posted by StealthFox
yeah dude, you're a little neurotic, the only time when you're going to run too cold is during your warm up period. and id never thought i'd see a thread like this in the third gen section where im supposed to be reading about people overheating thier motors from idling... geesh


and sorry for the thread hijack but im a newb and dont want to start a new thread. what temp do you guys with the manual fan switch mod flip it on? and when is the terminally highest temperature you can operate at, as in as high as you possibly can without damaging the motor

also a newbie with the same question
Old 06-19-06, 11:38 AM
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I have a manual fan switch. I flip it on at 70C and thats when I allow myself to get on it (double throttle plates and accel warmup removed). Dunno what that is in F.

On a side note, a correctly oporating thermostat wont allow you to run "too cold." It'll just stay closed till it gets warm enough, open, cool down, then close back up.
Old 06-19-06, 12:10 PM
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I don't flip on my fans until about 89C-90C. running 65/35 coolant mix.
Old 06-19-06, 05:40 PM
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Say you have your fans on well below the tstat opening temp(below 80C). What if you engine coolant is way hotter than the radiator coolant? If this happends will the Tstat not open for circulation and cause engine failure?

I would personally say setting the fans to go on when the tstat is fully open or just slightly before Aprox. 95C? What you think?

Last edited by RSXJOSH; 06-19-06 at 05:45 PM.
Old 06-19-06, 05:52 PM
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Fans cool the coolant in the radiator. They have nothing to do with the t-stat. The engine heats the coolant until the t-stat opens. When it opens, it allows cooler coolant to enter the engine.

Turning your fans on at a certain temperature is a matter of choice. I like to make sure that I turn them on well before I reach my destination. This ensures that the engine temps will be as low as possible when I shut the engine down. I also like to keep the coolant temp under 210, so I will turn on the fans accordingly.
Old 06-19-06, 09:22 PM
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Originally Posted by StealthFox
yeah dude, you're a little neurotic, the only time when you're going to run too cold is during your warm up period. and id never thought i'd see a thread like this in the third gen section where im supposed to be reading about people overheating thier motors from idling... geesh
Oh really? Then you haven't seen the 1001 threads about colder t-stats (below operating temp, such as 160 degrees), and not using a t-stat at all? If you lurk the forum long enough, you'll see threads about just about ANYTHING here
Old 06-20-06, 01:39 AM
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yeah thats true, this is the third gen section where anything goes.
Old 06-20-06, 01:42 AM
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Originally Posted by adam c
Fans cool the coolant in the radiator. They have nothing to do with the t-stat. The engine heats the coolant until the t-stat opens. When it opens, it allows cooler coolant to enter the engine.

Turning your fans on at a certain temperature is a matter of choice. I like to make sure that I turn them on well before I reach my destination. This ensures that the engine temps will be as low as possible when I shut the engine down. I also like to keep the coolant temp under 210, so I will turn on the fans accordingly.
that sounds like a good idea, i want to do this mod so i can start doing that and toss out that rediculous turbo timer
Old 06-21-06, 07:18 PM
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Originally Posted by kuroi FD
Double throttle plates? Who has those? lol
Yea pretty much.

Although it's fun to see people posting when they're trying to remove them for the first time.
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