1989 Ford Ranger with 2.3L engine
This engine runs cold and never gets to operating temperature. ECTS always shows a code 21. I put card board on the radiator and temp went to normal and no codes. Engine even sounds better.

I changed the thermostat but still same code 21 and engine runs cold.

Any idea?

Andrew

 

Not sure what a 21 code is off the top of my head but what temp stat did you put in? You should be running a 195 stat. If that is what you have i'd change it again cause you probably got a bad one, it happens. If you put cardboard in front of the rad and it came up to temp that tells me your stat is wide open. Hope that helps. Carl

 

A code 21 says ECTS out of spec. So I changed it out also along with the thurmastat. I went to Autozone and got their version and it's a 192 degree. I have since gone to Ford and got the motercraft version and it's 192 also. I'll change it Monday and get back. Andy

 

Well I changed the thurmastat again and still engine runs cool. I heard there was a TSB about low/eradic temputure sensors??? Anyway still get code 21 ECTS out of spec. Is there a chance that a dead cylinder would keep the engine cool?

Andy

 

I found the TSM on Alldata about the gauge sensor (singal wire)
95132 950703 Temperature Gauge - Reads Low/Erratic. I can block the rad and engine gets near normal temp. like between "N and R".