Ranger 2.3L coolant temp

[fratermus]

The Duratec 2.3L appears to be sending a head temp* rather than a coolant temp;  normal operating temps show up as 240-260F.  This occurs with both UltraGauge and Scangauge, so it's the truck rather than UG.

Evidence:
http://www.ranger-forums.com/showthread.php?t=106888
http://www.therangerstation.com/forums/showthread.php?t=12197
http://www.ranger-forums.com/showthread.php?t=79405

The truck drives, smells, and feels fine at this reported temp.  The stock gauge reads normal with no 'check gauge' idiot light.  Temp gun confirms normal temps in the hoses and radiator. 

Since the stock gauge trips the alarm at 250F this results in semi-constant alarms.  I am going to set my temp alert at 275F based on the following logic (using 190F as normal and 210F as overheating):

1. if the reported temp is ~33% higher than coolant, a useful alert might be ~275F
2. if the reported temp is an absolute ~65F higher than coolant, a useful alert might be ~280F
3. picking the lower of the two to be safe = 275F.


* or something.

[Tiger-Heli]

That seems logical, but I wouldn't worry about it all that much.

My Focus has the opposite problem - it is supposed to have a CHT and no coolant temp sensor according to Haynes, but UG shows 195-235 on the CWT gauge.

But I bought the UG mainly b/c the analog gauge reads right in the middle except one time that the fan resistor broke and the gauge read "a bit hot".

I found out the Low speed fan should kick in around 225-232 and the HSF should kick in around 240-245.  Based on that, I left UG at 250, but I'll probably watch the analog gauge and if it gets hotter than I think it should be, I'll probably set the alarm for that reading (or 250 - whichever ends up lower).  I've had the UG for 3 days and have seen 236 on it and the analog gauge was dead set in the middle.

The above is probably the best for you as well.