T-stat bad?

[07lariat]

Recently I've noticed that my delta has increased. Not so much from the eot increasing but the ect not getting to temp. I'm running between 182 - 186 in town and 186 - 192 highway. Could the t-stat be failed open?

[pizza pig]

the OEM Ford t-stat is partially open at 182* and fully open at 192*

pretty sure those are the numbers

[2 stroker]

Originally Posted by 07lariat

Recently I've noticed that my delta has increased. Not so much from the eot increasing but the ect not getting to temp. I'm running between 182 - 186 in town and 186 - 192 highway. Could the t-stat be failed open?

From what i have see by my coolant flushing and changing out my t/stat yours could be stuck open better than closed. A stock t/stat starts to open at 192.2* and is fully at 219.2* the back side of a stock t/stat is stamped 89/104*C Celsius to Fahrenheit converter | Celsius-Fahrenheit.com When replaceing a t/stat use only Ford 3C3Z-8575-AA Thermostat with housing
2 stroker

[thomaslord84]

How cold is it where you are? My truck was running around 186 cruising @ 65 so I thought that mine was bad, bought a brand new one from Ford and I still run 186 @ 65. That's all with outside temp around 50f. When it's 100+ outside I run around 194 @ 65.

[07lariat]

It's been hovering around freezing for the past several days here (central Ontario). If the t-stat is failing does it affect the eot as well or just the ect?

[thomaslord84]

If you have the stock oil cooler your ECT is going to have a rather large effect on EOT. If you have the BPD oil cooler it will still have an effect but not as much.

[travelin_farmer]

Originally Posted by 07lariat

It's been hovering around freezing for the past several days here (central Ontario). If the t-stat is failing does it affect the eot as well or just the ect?

I believe my t-stat is partially stuck open (have not had time to replace it yet) and i have observed ECT at 60 mph @ 184 degrees and EOT steady at 188. That is with outside ambiant temps of below freezing. In fact when the outside temp is around the freezing mark, i would not see EOT above 190 unless i put my foot in it...

[worldwide73]

You should be running about 192-196 with a good new thermostat. Between 35-50 degrees outside temp where I am.

[cdelap]

I am pretty sure my t-stat failled this weekend, this past weekend towing my 10k fifth wheel in 40* weather my ECT was ~176-179 and E)T was 185~190. I typically have a ~7* delta while towing my camper but was in the 10-11 degree range this weekend. Is it likely that my delta was larger due to the truck not running at temp or is time to flush the system? I checked the fluid and it is all good

[Rhys05]

Originally Posted by pizza pig

the OEM Ford t-stat is partially open at 182* and fully open at 192*

pretty sure those are the numbers

It starts to open at 89C and is fully open at 104C...so that is 192F and 219F respectively... Mine was running in the low 180s, I replaced my thermostat and now it is pretty steady at 190F..that was with it cold and rainy, so I would imagine that if it isn't rainy it will be ~192F or so.