I installed a non-electric thermostat in my 2003 about a month ago. I went with a 2006 Motorcraft 195*. So far so good. There have been no problems with the truck at all. The temps did drop by a few degrees but nothing major. I now run about 208*-212* ECT and about 241*-245* CHT solidly. There are a few others on this forum or maybe it's another Ranger forum that have been running without an E-thermostat for a year or two with no issues.
For the moment I have left my old thermostat connected and zip tied up and out of the way. But, I have purchased a 1500ohm chassis resistor to wire in to take the place of the old thermostat. This way it won't trip the CEL. I'm just trying to figure out how I can make the resistor plug-n-play with the existing harness so if I do decide to go back to the E-Thermostat I easily can.
DISCLAIMER: You do this at your own risk. I use my truck for the occasional dump run and hauling stuff for people. The speed limits around here are 55 mph so I've never had it up to 70 or 80 mph. And I have never towed with it. But for the light loads and trips to the dump it's not had a single issue that could be related to running a non-electric thermostat. If this were my daily driver or my bread and butter then I would have stuck with the E-thermostat.
Last edited by Soledad; 06-22-2016 at 01:36 PM.