• Register Today It's free! This box and some ads will disappear once registered!

  • Holiday Special! - 2 for 1 Elite Explorer sale!

    Right now you can purchase an Elite Explorer membership for $20 and receive a two year membership!

    Click Here to start your membership and get rid of the ads!

Custom 170° thermostats


jrgoffin

Elite Explorer
Joined
January 3, 2010
Messages
193
Reaction score
34
City, State
The midwest
Year, Model & Trim Level
'20 Explorer ST
EDIT: I had to make a correction to the original post since I inadvertently added a DIY document that only applies to the 5th Gen Explorer. My apologies since I mixed up the part numbers. This is the correct method to knock out this thermostat easily.

----------------------------------------------------------------------------------------------------------------------

My main involvement with the car scene has been with the '03-'04 Cobra "Terminator" crowd that has gone back many years, including my own web site dedicated to the vehicle and its history: www.terminator-cobra.com. One of my side projects, that is on hold now due to the insanity of 2020, has been a customs Stant 170° thermostat (Stant is the OE supplier, by the way). You can buy them on-line for something like $70, but since I decided to take a break - and may not ever get back to it - I decided to share the "secret" of them for anyone that has just basic mechanical skills and wants to save some coin.

For about $20, this is a total DIY project that takes about 5 minutes and is laughably simple. Since the factory RT1225 thermostat is a 190° version, many might want a lower-temp 170° after getting tuned and modified. All you need to do is buy a Stant 14138 (180°) and 14147 (170°), make a quick part swap, then add a gasket to its flange and you are done. The gasket is also easy to acquire as a Stant 25282 (the same as NAPA 1093 or FelPro 35710).

Here is the 14138 (both MUST be from Stant, easily identified by the blue & yellow box!):

Stant 14138.jpg


With this in hand, you just need to pull out the brass 'foot' and its internal spring. The spring sits inside with a larger coil on the bottom, and then will be transferred to the other thermostat. You can then toss the main thermostat body. Here's what you have once the 'foot' is removed:

20200807_190534.jpg


The Stant 14147 looks like this, which is the 170° base that has a 56mm OD flange compared to the 54mm flange of the 180°:

Stant 14147.jpg


You simply then snap the brass foot and spring back in the bottom of the 14147, then add the gasket to the flange which brings the diameter up to 61mm for a proper fit in the housing (this thermostat also fits the Ford Coyote 5.0 V-8):

P1040960.JPG


In the above image, which is then the final product, note the orientation of the gasket since it has a flat side that faces down. The internal groove will fit right over the flange of the 56mm 14147 housing and you are good to go. As an FYI, here is the OE Motorcraft (also made by Stant) RT1225 190° thermostat. It looks a bit different, but the dimensions are the same as above:

BR3Z8575D-FRO__ra_p.jpg
 








Spacey

Member
Joined
October 24, 2019
Messages
94
Reaction score
19
Year, Model & Trim Level
2020 Explorer ST
Isn't the engine and cooling system going to end up at the same temperature. It will just take a little longer as the thermostat opens earlier. What am I missing?
 




jrgoffin

Elite Explorer
Joined
January 3, 2010
Messages
193
Reaction score
34
City, State
The midwest
Year, Model & Trim Level
'20 Explorer ST
The fan on/off speeds get reset when tuned. With my Cobra for example the engine is always in the 170's - 180's with the lower-temp thermostat and adjusted fan settings. Compare that to 200°+ with the OE settings and thermostat. Not a huge market for thermostat swaps when it comes to the Explorers, but for those that want/need one, this is a quick and easy way to go.
 




Top