Since I put my Edge Programer on my truck I always pay attention to the Engine Core Temp. It is usually right around 186 degrees. We have been having some hotter weather here and I have noticed that the ECT has now gone as high as 208 degrees. Is that too high under normal driving conditions? I have a 03, screw 5.4ltr

Could I need a RAD flush?

 

That is a lot of fluctuation and sounds to me as if you are having some blockage. Either thermostat or radiator.

As to your question about temp, Troyer posted about 3 years ago that the optimum efficiency temp for the Triton was 210. That is why we have 195 thermostats. Mine ranges from 190 to 196 at all times unless it it very cold and it will go down to 188 or so.

 

mine fluctuates between 195-205 usually. Fact is I've never seen mine go higher then 205. Might try getting a new thermostat and flushing.

 

I just had my bank 2 cat replaced and still sporaticlly getting a code 0430 about cat effecincey below threshold. Could that contribute?

 

If you have a stock thermostat installed, your readings are pretty normal, especially in hotter weather.

 

i've seen 210 once. it was in traffic on a hot day though.

just keep an eye on it and as long as the temp is not spiking, everything is fine. coolant interval is 60,000. if it's been that long go ahead and do it. couldn't hurt anything.