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Why Won't ECT Reach 181* ?

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Old Feb 6, 2017 | 07:50 PM
  #1  
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Why Won't ECT Reach 181* ?

Hi guys, new oem thermostat, new coolant temp sensor. Took a 200 mile trip at highway speeds, (65-85 mph) and my coolant range was between 159* and 165*. The EOT was between 200* and 204*.

Why won't it warm up? Can an EGR delete cause the cold nature due to no exhaust temperatures reaching the EGR cooler and the engine coolant?

Should I try the Mitso 200*? or could the motorcraft thermostat be malfunctioning?
 
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Old Feb 6, 2017 | 08:32 PM
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Did you buy the thermostat and housing combo or just the thermostat? When I replaced mine with the Mishi I noticed my housing was worn to one side so I replaced the housing. Did you check to make sure it was seated correctly in the housing before install?
 
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Old Feb 6, 2017 | 09:48 PM
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Sounds like it's stuck open. After reading so many posts about the hi dollar mishimoto tstats needing to be boiled to open all the way first to ensure proper seating, I decided to boil my gates tstat before i put it in. It just seems like the extra 15 minute procedure at the kitchen stove is definitely worth doing on ANY tstat prior to install and makes a whole lotta sense imo.
 
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Old Feb 6, 2017 | 09:51 PM
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Originally Posted by OneCylinder
Hi guys, new oem thermostat, new coolant temp sensor. Took a 200 mile trip at highway speeds, (65-85 mph) and my coolant range was between 159* and 165*. The EOT was between 200* and 204*.

Why won't it warm up? Can an EGR delete cause the cold nature due to no exhaust temperatures reaching the EGR cooler and the engine coolant?

Should I try the Mitso 200*? or could the motorcraft thermostat be malfunctioning?
Am I the only one seeing the EOT/Coolant delta and am a bit worried?

Richard
 
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Old Feb 6, 2017 | 10:00 PM
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Originally Posted by DarkStarMedia
Am I the only one seeing the EOT/Coolant delta and am a bit worried?

Richard
Delta isn't of concern unless the coolant system is operating normally. Coolant temp must be in the normal range first before true delta is an issue.
 
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Old Feb 6, 2017 | 10:56 PM
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EOT is about where it should be if coolant temps are normal, so I'm actually a little skeptical of the ECT sensor on this one. Might be worth verifying that the cold temp reading is accurate.
 
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Old Feb 6, 2017 | 11:25 PM
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FiznUKa
No, I had my local shop do the work.

Bumblebee04
Looks like it's coming out for a trip to the kitchen. Seems to me that Motorcraft is having QC problems. The original stuck closed on me. Good thing that I noticed and shut her down. Also out of a set of 8 reman Motorcaft injectors, 3 have been waranty replaced.

DarkStarMedia
I agree with Bumblebee04, the EOT is where it should be.

seijirou
The temp sensor was replaced with the tstat, however you have a good point. How can there be a +/- 40* difference between the two fluids. I think I'm going to start with the sensor connector.

Thanks guys
 
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Old Feb 7, 2017 | 01:23 AM
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The further away from 200f your coolant is, the higher your delta is going to be. With an OEM thermostat, you should see at least 190f cruising on the highway. With a mishimoto 200f thermostat, the "magic" 15f delta cutoff becomes a 12-13f delta cutoff.

Something is out of whack if you are seeing coolant temps that low. There is a possibility you got a bad thermostat out of the box. There is also a good chance that the thermostat housing is aftermarket and the OEM thermostat is opening prematurely as a result.
when i upgraded to a mishimoto 200f t-stat, i noticed the existing aftermarket thermostat was a different length. I bit the bullet and bought a new OEM t-stat housing (dealer would only sell it with a new t-stat). The OEM t-stat was the exact same length as the mishimoto. I installed the mishimoto with the motorcraft housing and had no issues. If i had noticed the difference in time, the mishimoto t-stat would have likely still fit in the aftermarket housing, leaving me with further issues.
 
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Old Feb 7, 2017 | 01:51 AM
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brandonrr
So they make aftermarket tstat housings that are dementionaly different than OEM? If so that makes sence, I had the radiator and tstat replaced a couple of years back. That shop may have used the aftermarket housing and tstat (I had no problems then). The new shop used a Motorcraft tstat and if they're not compatible, I may have a bypass situation.

Thanks
 
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Old Feb 7, 2017 | 07:43 AM
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Mishomoto, from what I have read, has taken care of the issues of fitment. Not saying there is not any NOS stuff out there.
 
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Old Feb 7, 2017 | 08:12 AM
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I'd start with a cold reading to verify both are close in temperature to say... they work.
Next is the connector, mine does this occasionally, wiggle the connector, readings change. Next boil the t-stat and verify the fitment with the housing in the pot with the T-stat... go from there, its good or bad, doesn't fit, won't fully open/close or you have a connector issue.
 
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Old Feb 7, 2017 | 11:13 AM
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Originally Posted by OneCylinder
brandonrr
So they make aftermarket tstat housings that are dementionaly different than OEM? If so that makes sence, I had the radiator and tstat replaced a couple of years back. That shop may have used the aftermarket housing and tstat (I had no problems then). The new shop used a Motorcraft tstat and if they're not compatible, I may have a bypass situation.

Thanks

The parts store thermostats come with the housings. The autozone unit that was in my truck was shorter than OEM.
 
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Old Feb 7, 2017 | 11:16 AM
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Originally Posted by OneCylinder
Hi guys, new oem thermostat, new coolant temp sensor. Took a 200 mile trip at highway speeds, (65-85 mph) and my coolant range was between 159* and 165*. The EOT was between 200* and 204*.

Why won't it warm up? Can an EGR delete cause the cold nature due to no exhaust temperatures reaching the EGR cooler and the engine coolant?

Should I try the Mitso 200*? or could the motorcraft thermostat be malfunctioning?
How many miles on this motor?
 
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Old Feb 7, 2017 | 09:00 PM
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There is about 30k on the engine.
 
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Old Feb 7, 2017 | 09:34 PM
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Block the entire front of the radiator with a sheet of cardboard. Watch the temp closely. If it comes up into the 186+ operating range then the thermostat is prematurely opening. If you allow it to get warm enough you'll also hear the fan speed ramp up. Remove the cardboard and watch the temp drop. Replace thermostat.
 
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