Ford EcoBoost 170 degree thermostat Reische Performance

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It is now that time where we are entering the summer months and its getting above 80 degrees outside. The standard operating temperature of the 2018 Lincoln Navigator L seems to be between 210-220 degrees which has always seemed too hot to me. Time after time Ive been shown charts and data throughout my entire life which demonstrate that temperatures like that always lead to premature failures like transmission failure. So I decided to try out the Reische Performance 170 degree thermostat for Ford Ecoboost engines like in the F150. There were a few tricks to getting out the thermostat. The first step is to drain the coolant and there is a reddish drain knob under the vehicle on the drivers side. Its between the left frame rail and tire towards the front. It stands out as its the only red knob under there. If you turn that knob and have the coolant reservoir cap open it will be coming out fast. The other tricks to getting out the thermostat was the gymnastics under the hood. Squeezing my hand into the tight space of the engine to turn little bolts and not losing the tool or the bolt in the process...not fun. At one point I had to remove a large tube on the air intake to gain access but then it took a long time to figure out how to get it back on as more underhood gymnastics was required. When I say not fun, got very dirty, got a few small cuts with blood everywhere and took a lot of time trying to figure out how the air intake hose went back on. When I was done reinstalling everything I added coolant. This was a process because I filled the reservoir up to the top but as the engine warmed up it seemed to need a bit more. So had to monitor the coolant level for a bit. I poured the old coolant with a funnel into the empty coolant bottles that I used to pour the new coolant in. It was about 1-2 bottles of coolant used to refill it. I dont think all of the coolant comes out when you turn that red knob but about 5-6 quarts. I tested it out by driving around for about 20 minutes with full air condition and the vehicle in "Excite" or sport mode with the all wheel drive engaged. Then doing some spirited runs around town. I was able to get it up to 203 degrees maximum. Later on when I was cruising on the highway I found I was able to sustain about 190 degrees. It was 86 degrees out by the way. Usually on such spirited runs I would get the temperature up past 220 degrees easily. From what I read in order to get the maximum benefit from this thermostat I need a "tune" which would set the fans to engage at different temperatures. However, I found that I was getting enough benefit as it was without the "tune". Operating temperatures were quite a bit lower. The story does not end here. Im going to monitor the fuel efficiency of the setup and I might or might not keep it depending upon what I experience mpg wise. There is a Motorcraft 180 degree thermostat available and you can find that one by ordering the thermostat for the 2019 Lincoln MKT Livery. I recently did a coolant flush on that one and put in a new thermostat and found its exactly the same size as the one in Navigator but its set for 180 degrees. Let me explain something about thermostats. When the thermostat is rated for 190 degrees it does NOT fully open at 190 degrees. It will start opening and then somewhere north of 210 degrees is when it fully opens. So the 170 degree thermostat will start to open at 170 and then fully open somewhere above 190 degrees. The Reische Performance thermostat has been out there for years and I found forum posts some 6 years old. I think this modification is a no brainer and should be done right away with any Ecoboost engine. The only question I have right now is about fuel economy with this setup...another question is how will it do in winter and maybe I should switch to the 180 or 190 when that time comes. A lot of people seem to be in agreement that an operating temperature above 210 degrees is not a good thing. 180-200 is more preferable for reliability. I have no data or studies on that but it seems to agree with what Ive heard over the years about heat and engine/trans longevity. https://www.reischeperformance.com/index.html#anchor
 
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I am curious to see what your results will be because the engine programming is set to work at a certain temperature. 210 degrees is perfect and where it should be, that is what it is programmed for to keep things in check for both emissions and fuel economy. Depending on the parameters in your current tuning, you will probably get a check engine light for not getting up to temperature. That may take a while since it usually gives a chance to see if it may just have gotten stuck etc. It will probably keep your transmission cooler obviously since the radiator most likely cools the transmission and radiator temps will be lower. Then again the reason I am curious is because there really isn't any "driving" in NYC. It is acceleration then stopping and sitting in traffic or at a light. I used to live there and the driving patterns are very different than where I am now, for example. Since you accelerate so much and sit so much, it may stay warm enough to not trip the check engine light. But if you were to take it on a long highway cruise at 75 MPH, which is the speeds we drive here, I am almost sure it would give you a trouble code for thermostat temp. That is why you need a tune to do a lower temp thermostat. Many different parts of the tune require changes. You may also find transmission issues such as not allowing lockup or blocking certain higher gears if the tranny doesn't warm up enough either. Also keeping the engine too cool will usually end up causing the engine to sludge up eventually since it can build up moisture inside from not getting hot enough. Way too many variables, but there is a reason why it was set to run at that temp and messing with it will screw up everything else like a domino effect. Best of luck and will stay tuned for the long term results, please keep us posted on what happens.
 
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Originally Posted by Chris142
A thermostat only controls the minimum temp. Once the thermostat is open it no longer controls the temp. I bet that it still hits 220.
^^^ Exactly. Or maybe your gauge is off... or were you using a scantool or similar device?
 
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The tune is to fix idle temps, without it the coolant will still get up to the normal temps at idle before kicking them on. The fan running for AC will mask that issue somewhat.
 

Navi

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The reason why Im doing this is to roll back the fuel economy measures imposed upon us. Right around 5 or more years ago it seemed like everything on cars seemed to change from gas saving tires to the temperature they operate at to the thickness of the oil...not just motor oil but ATF and gear oil. These changes squeezed out small gains in mpg but shortened the life of the vehicle. I have no scientific study to go by but I can point out the 2014 vs 2015 Suburban. The 2014 Suburban had rock solid reliability. It used 5W30 oil, thicker trans fluid, 180-200 degree operating temperatures, etc. When the 2015 Suburban came along the operating temperature moved up to 220 degrees, 0W20 oil, gas saving tires, etc. They were able to squeeze 1 more mpg out of the thing but the 2015 was a disaster reliability wise. The trans on the 2015 failed.at 80 to 90k. Many 2015s nowadays are no longer on the road but still plenty of the older ones are still there...
 

Navi

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Please be kind when I do the mpg analysis. I am going to use the infamous trip computer to do it. Ive been made aware many times by numerous internet aliases of how inaccurate they can be. However this isnt Consumer Reports and I dont have the resources they do to conduct such an analysis so understand this is my "best effort" even though it may not be the best method.
 
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Originally Posted by Navi
It is now that time where we are entering the summer months and its getting above 80 degrees outside. The standard operating temperature of the 2018 Lincoln Navigator L seems to be between 210-220 degrees which has always seemed too hot to me. Time after time Ive been shown charts and data throughout my entire life which demonstrate that temperatures like that always lead to premature failures like transmission failure.
What transmission temperatures have you observed? I think the factory on/off temperatures of the electric fans have more to do with the engine temperature in traffic than the thermostat.
 

Navi

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The fuel dilution on this vehicle and engine have an issue. I know if you use any garden variety 5W-30 in it then it will dilute down to the 8s. Im not sure if its either dilution or shear which are different concepts but the effect is the same in the viscosity falls to 7s-8s which makes you wonder if that will effect engine longevity/reliability. Im not certain if the engine operating temperature has anything to do with the fall in viscosity however.
 
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Note that running too cool an engine temp increases wear. I recall a study that indicated that the "sweet spot" was around 180-190F, below that, wear was increased significantly. Above that, wear didn't really increase, but there were power losses but improved emissions performance and fuel economy.
 
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Does your Navigator Show oil temp like the newer F-150s do? I'd be curious what the temps were before and after the thermostat swap.
 
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Originally Posted by RhondaHonda
Does your Navigator Show oil temp like the newer F-150s do? I'd be curious what the temps were before and after the thermostat swap.
I have a 2019 F150 with the high output 3.5 Ecoboost. The only oil temperature it shows is the transmission oil temperature. It doesn't show engine oil temp. In fact, unless you have downloaded Forscan, and modified the ECM programing a bit, you won't even see actual trans oil temps, until the transmission gets dangerously hot. Using Forscan, you can have the trans temps and coolant temps digitally displayed above the analog gauges all the time. I did this mod on my truck. I also have a Reische 170 thermostat, but have yet to install it. I was seeing 220 degree coolant temps routinely in normal driving. Since unplugging the shutters which regulate air flow through the radiator, coolant temps are 10 to 15 degrees cooler. Why the shutters are there other than to keep the engine artificially hot is unknown. When connected, the shutters only open under acceleration, and close on cruise or low throttle. My truck has a 195 degree thermostat as OEM. The reason I've not yet installed the 170 T-stat is I cannot find what triggers the Ecoboost to switch from open loop operation after startup, to closed loop. On most vehicles, coolant temperature reaching a certain point is that trigger. Older Fords made that switch based on time after start only, but I can't find anything about the later models. If the engine stays in open loop continuously, mileage will take a serious hit.
 

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Originally Posted by Tim_S
Originally Posted by RhondaHonda
Does your Navigator Show oil temp like the newer F-150s do? I'd be curious what the temps were before and after the thermostat swap.
I have a 2019 F150 with the high output 3.5 Ecoboost. The only oil temperature it shows is the transmission oil temperature. It doesn't show engine oil temp. In fact, unless you have downloaded Forscan, and modified the ECM programing a bit, you won't even see actual trans oil temps, until the transmission gets dangerously hot. Using Forscan, you can have the trans temps and coolant temps digitally displayed above the analog gauges all the time. I did this mod on my truck. I also have a Reische 170 thermostat, but have yet to install it. I was seeing 220 degree coolant temps routinely in normal driving. Since unplugging the shutters which regulate air flow through the radiator, coolant temps are 10 to 15 degrees cooler. Why the shutters are there other than to keep the engine artificially hot is unknown. When connected, the shutters only open under acceleration, and close on cruise or low throttle. My truck has a 195 degree thermostat as OEM. The reason I've not yet installed the 170 T-stat is I cannot find what triggers the Ecoboost to switch from open loop operation after startup, to closed loop. On most vehicles, coolant temperature reaching a certain point is that trigger. Older Fords made that switch based on time after start only, but I can't find anything about the later models. If the engine stays in open loop continuously, mileage will take a serious hit.
Closed loop having ECT as a parameter has been around since EEC-IV FYI. That's another reason a 160 t-stat in a 302 was a bad idea beyond higher wear. IIRC, the temp was ~170F to switch to closed loop, which made me safe with my 180.
 
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Iirc, ford tries to minimize shutter opening unless it's anticipated for cooling demand or AC. The closed shutters improve aero. The fan thing is a complaint on some of the performance forums. I'm not sure if it's warranted, as these engines aren't known to have heat related issues and lots of RVers are towing just fine with stock ecoboosts all day long. But, some of the guys have noted that ford doesn't engage the fans outside of AC demand until the stock t-stat should have opened a good bit. I'd bet a dollar that they reduce them at highway speeds due to natural airflow. So, if you put in the lower t-stat, I'd anticipate tuning that, or possibly expect a wider swing of operating temp range. Unless you're trying to raise the boost on the thing, I'm really not sure I'd alter much with it. It is pretty highly engineered. For an example of this, search for the pdf of ecoboost fuel delivery programming that people have been talking about. Ford really put the effort into these. Ive always been a foreign car guy, but the f150, even with all its plastic, has become my favorite vehicle. They got a lot right with it. M
 
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Originally Posted by Tim_S
Originally Posted by RhondaHonda
Does your Navigator Show oil temp like the newer F-150s do? I'd be curious what the temps were before and after the thermostat swap.
I have a 2019 F150 with the high output 3.5 Ecoboost. The only oil temperature it shows is the transmission oil temperature. It doesn't show engine oil temp. In fact, unless you have downloaded Forscan, and modified the ECM programing a bit, you won't even see actual trans oil temps, until the transmission gets dangerously hot. Using Forscan, you can have the trans temps and coolant temps digitally displayed above the analog gauges all the time. I did this mod on my truck. I also have a Reische 170 thermostat, but have yet to install it. I was seeing 220 degree coolant temps routinely in normal driving. Since unplugging the shutters which regulate air flow through the radiator, coolant temps are 10 to 15 degrees cooler. Why the shutters are there other than to keep the engine artificially hot is unknown. When connected, the shutters only open under acceleration, and close on cruise or low throttle. My truck has a 195 degree thermostat as OEM. The reason I've not yet installed the 170 T-stat is I cannot find what triggers the Ecoboost to switch from open loop operation after startup, to closed loop. On most vehicles, coolant temperature reaching a certain point is that trigger. Older Fords made that switch based on time after start only, but I can't find anything about the later models. If the engine stays in open loop continuously, mileage will take a serious hit.
I have a 2019 Raptor and can display oil, trans, intake air before and after the intercooler and other gauges on mine. I figured they all could do this. Tried to upload pics but they wouldn't go.
 
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It's nice Ford provided that level of drivetrain monitoring on the Raptor. Since my Limited has the same drivetrain (engine and transmission) as the Raptor, one would think Ford would have done the same on the Limited, but no. Intake air temps before and after the intercooler are available, but not engine oil temperature. Just like the phony oil pressure gauge. It' just a fancy idiot light. From what I've read, and I don't know if it's true, some years ago, the oil pressure gauge on F150's (and I'd guess other Ford vehicles) was a true oil pressure readout. Unfortunately, Ford received too many complaints that the oil pressure readout "didn't remain constant, but moved up and down". I guess those complainers were ignorant of the fact that oil pressure fluctuates with engine rpm, particularly between idle and while driving, cold vs hot. So Ford "fixed" it. The "oil pressure sender" is a simple on and off switch, which the ECU interprets as a 3/4 gauge sweep which stays constant.
 

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Originally Posted by Tim_S
It's nice Ford provided that level of drivetrain monitoring on the Raptor. Since my Limited has the same drivetrain (engine and transmission) as the Raptor, one would think Ford would have done the same on the Limited, but no. Intake air temps before and after the intercooler are available, but not engine oil temperature. Just like the phony oil pressure gauge. It' just a fancy idiot light. From what I've read, and I don't know if it's true, some years ago, the oil pressure gauge on F150's (and I'd guess other Ford vehicles) was a true oil pressure readout. Unfortunately, Ford received too many complaints that the oil pressure readout "didn't remain constant, but moved up and down". I guess those complainers were ignorant of the fact that oil pressure fluctuates with engine rpm, particularly between idle and while driving, cold vs hot. So Ford "fixed" it. The "oil pressure sender" is a simple on and off switch, which the ECU interprets as a 3/4 gauge sweep which stays constant.
Yes, and Ford isn't the only brand to have used a switch for the cluster display of oil pressure either. The transition started sometime in the 1980's IIRC. Cars like the Mustang had a large bell-shaped oil pressure sender, which provided real oil pressure to the gauge. Cars like the Town Car had a pressure switch that triggered the oil pressure light or if a gauge was equipped, it always sat at the same position unless pressure dropped below 5psi IIRC.
 
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