Perplexing temperature problem

[jelloslug]

I'm having an ongoing "overheating" problem. I use overheating loosly because I have never seen any physical problems that are related to overheating. I only see it on my gauge (aftermarket gauges). I also see a drop in oil pressure that goes along with the temperature rise. The problem has carried over from my old 3.0 to my 3.2 so I'm kinda sure that it's not an engine problem. I not getting any codes or having any other running problems and I am getting decent gas milage (22 MPG, dang lead foot ). The ETC sensor has been replaced and replaced again, I just installed a new double core radiator, a new cap (old one was bad), and the t-stat is around a year old (it seams to be working fine). Idling in the driveway the gauge will go to around 245 F and then the fan kicks in, it will go down to around 220 F and then the fan kicks back off. It never boils over or runs odd, even when the gauge reads 245 F. On the highway it will run between 185 to 215 depending on how hot it is out. Any suggestions? I'm at a loss...

 

[projectSHO89]

I would be suspicious of your guage sending unit or guage. 245 is pretty extreme for an indicated fan turn-on point.

Steve

 

[yamahaSHO]

I know you replaced your ECT, but that sounds exactly what mine did when the ECT went bad.... Wonder if the connection or a wire is bad?

 

[Slo-Sho]

A tool such as this will help in the process of elimination.

 

[jelloslug]

Actually I'm going to instrument it with a real, calibrated thermocoupler. Those infrared units are not very accurate at all unless your spending mucho $$$ on it (I know, I have one of the cheap ones). I'm suspect of the thermostat since it seem to be acting a bit erratic also.