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206* Normal Operating Coolant Temp? *UPDATE*

JSchleim18

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Oct 16, 2006
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Long Island, NY
Just wondering if this is normal. I have the stock 193* or so thermostat, 1.3 bar radiator cap, aluminum radiator, FMIC, single puller fan and custom shroud.

The coolant temps read 206* in normal cruising on a 65* night. It got as high as 210* at 60 MPH.

Should I try to 180* thermostat to lower my temps?

What could be causing the higher than what I'm seeing from everyone else coolant temps?

Thanks
 
Last edited:

Polish

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Jan 10, 2005
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NE, IN
That is about what mine always ran at too. As long as it doesn't get over 210°ish and the fan can keep it there or lower, it shouldn't hurt anything. Those are normal stock operating temps.
 

trunks

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Feb 5, 2010
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Annandale, MN
This is what I'm seeing too and was thinking the exact same thing /ubbthreads/images/graemlins/dunno.gif
 

beaner

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I too am trying to figure out the optimal temp range for my car, as far as ECU/timing goes. I believe before 179 and after 206 the ecu pulls 1 degree of timing _however_ at ~186 the ecu will switch into closed loop. So 190-200 seems to be the happy spot. This is all from searching around YMMV.
 

trunks

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That's interesting as I was getting an intermitant cel that I believe was for knock when accelerating at times (until I turned it off with link) which makes sense. So we appear to be running too hot then? I just replaced my radiator and fan as well and the temps seem to still be climbing over that 200 range.
 

SouthCaliVR4

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Jul 31, 2010
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North county San Diego
Cruising down the freeway you should sit where the t-stat is rated (ish). around town your fan switch will become the thermostat. I believe the fan switch turns on around two ten & off around 190. if your seeing higher temps at cruise, check the stat & your rad core. to low on the cap pressure can also let the water pump cavitate at higher rpms leading to higher temps.
 

Terry Posten

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Dec 16, 2003
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Davenport, Iowa USA
The 200+ temps are what the factory wants you to be at for emissions but it does not work really well for boost as this causes knock sooner. With a stock setup (ECU) just make sure it you keep it below 215.

With aftermarket setup (link or the like), set it up for 160. That way you can optimize your timing, fuel, and boost. After you reach 190, your knock chances go way up.
 

JSchleim18

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I was thinking about running the lower temp t-stat and using Link's Coolant Offset feature. Is that what you did Terry?
 

dsmless

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Jun 12, 2008
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tucson,az
I always change all my modified cars termostat to 180 and run with on fan on all the time in the galant the stock puller fan infront of the condensor will push alot of air and in 100 degree arizona weather with ac on it never went past 210 would sit at 190 this is with, stock pusher, a 14 puller and water wetter, a 50/50 coolant mix and a 1g aluminum radiator and 180 failsafe thermostat
 

SouthCaliVR4

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North county San Diego
Quoting JSchleim18:
I was thinking about running the lower temp t-stat and using Link's Coolant Offset feature. Is that what you did Terry?



Yea, that's what he's talking about.

Note if you don't have a way to modify this parameter in the ecu it will see this as a constant low temp situation & can cause driveability issues.
 

JSchleim18

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Long Island, NY
OK so I was thinking a little bit today...

I don't have AC so I took that temperature switch OUT and I moved the coolant temp switch from the radiator into that port (top port on t-stat housing). When the temperature hits 185*, that triggers the switch to run the fan on LOW. However, I have a 190* thermostat. So that switch isn't seeing any real reading until the thermostat opens at 190*. Once that opens, the fan then gets turned on and it's already "too late" aka pass the 185* mark when the fan should kick in.

So my solution here seems that I should just get a 180* thermostat and that should fix the issue. This will then allow the thermostat to open at 180* to allow the switch to activate at exactly 185* and kick the fan on.

Does this sound like a good possibility at solving my issue???
 

Brunoboy

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Apr 25, 2008
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San Bruno,CA Home of SFO
Sitting at idle today with a 190 thermo I reached 226F according to link with a full size push and slim puller.
 

beaner

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b'ham, mi
Couple things come to mind. Do you have the overflow hooked up? I've learned the hard way the overflow is pretty important. Are you sure the fans are pushing/pulling the correct direction? How are you adding coolant to the system? I always take the cap off before starting the cold engine, and add coolant until the engine is warmed up and done burping bubbles, then put the cap on.
 

JSchleim18

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Oct 16, 2006
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Long Island, NY
A little update.

I got the 180* Thermostat from JNZ Tuning. Drained my whole system. Put the 180* t-stat in and filled the system with 30/70 coolant to distilled water and a bottle of water wetter. Burped the system with the cap off until I couldn't fill it anymore. Put the cap on and squeezed the upper radiator hose a bit. Took the cap off and was able to add even more water. I did this about 3 times.

Fired the car up and it hit 193* when fully warmed up. Stayed there until I started moving. The car hovered around 196* around town and at freeway (65MPH) speed it was at 200*. Funny it's reading exactly 10* lower with a 10* lower thermostat.

This was on a 70* night outside.
 

belize1334

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Nov 18, 2003
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Bozeman, MT
Just be aware that the ECU has to read 197* in order for "learning mode" to kick in. If it never gets to that temp you're fuel trims will not update.
 

JSchleim18

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Oct 16, 2006
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Long Island, NY
Are you sure it's 197*? I'm looking on the ECMLink forum and it shows 190* so that would be OK for me.
 

Terry Posten

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Dec 16, 2003
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Davenport, Iowa USA
The ECU starts auto adjusting around the 190 mark but if you have a link, just offset that level.

Mine likes to run 10 degrees hotter than my t-stat as well. I figure that is just a product of the t-stat being at the hottest spot where water is just coming out of the engine.

The water going into the engine is probably 30-40 degrees colder.
 
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