Hello I am new here. I have an 03 Ranger with a 4.0. I have developed a water leak that I can not find. I have thrown money at by replacing the water pump, thermostat, and the hoses. My leak is in the front upper section of the engine. I can see anti freeze but I can not find the leak. There is what appears to be a temp sensor on the top of the motor. Has anyone had this problem and know where the leak may be coming from?

 

Unfortunately the plastic thermostat housing can start to separate along the seam connecting the top & bottom of the housing. If you see a pool of coolant under the intake, there's a good chance that has happened.
There is also the possibility that the O-rings for the temp sensors have deteriorated to the point of leakage, but it's less likely. A coolant system pressure test is the best route.

 

Thank you for the information it was very helpful. Unfortunately the intake manifold had to come off to get to it.

 

Actually it doesn't

Good read here WITH pictures: How To Replace the Upper and Lower Thermostat Housing on a Ford 4.0L V6 SOHC Engine

Your '03 will only have 1 Temp sensor on the housing, they dropped the 2nd sensor in '01/'02, but that's the only difference.
The temp sensor is "clipped" in, picture in above link, metal clip slides out sideways to release sensor.

 

I meant to correct you in an earlier post, this information isn't quite right. I had an 06 Ranger that still had two. My 07 only has one as well as the 05 Explorer SOHC that I have.


You don't have to remove the intake, but loosening it so you can lift it a little helps a lot! & removing it entirely isn't difficult.

It's very difficult to remove the thermostat housing without breaking the locating tabs on the bottom without the extra room. If they break, they end up in the coolant system & if you don't fish them out, could be an issue.

 

Thanks for the posts on V6~4.0L~SOHC engines & TStat housings; good reference info.
Replaced the old leaking FRPlastic TStat Housing with a new Aluminum TStat Housing
in 2019Aug on a 2001 Ford ExSportTrac; no leaks as of 2020Mar after ~5K more miles.
My full write up with pics on that repair:
http://2001fordexplorersporttrac.fandom.com/Coolant_ThermoStat_Housing