Engine temperature

I am looking for some help here. 1998 Legacy O B wagon with 2.5L DOHC, auto trans AWD & A/C. I have new cyl head gaskets, timing components, water pump, T-Stat, belts, hoses. 146,000 miles. It runs good, 3K miles since reinstall. 29 MPG, no SES light. I am a Suby novice. 1st one I have owned. With my scan tool I am watching engine temps, not sure if what I am seeing is normal. Running on the highway, it will run different temps at 65-70 MPH. Sometimes as low as 183, or clear up to 221 degrees F. Cooling fans work normally, coolant is full. Little difference with or with out A/C on. Its usually steady within 2-5 degrees. It seems to have no pattern that I can see. Ambient temps make no difference. When I come off the highway & turn down the dirt road to the farm, going from 65 MPH to 40 MPH the temp climbs to 221 or 223. I get that some fluctuation is normal. I cant see any external reason for this, thinking I will repl the T-Stat this weekend. It sure does not seem normal. I do not want to shorten the life of the engine here. Anyone seen anything like this? This range of temp cannot be normal in my humble opinion.

I suggest only using Subaru thermostats if you check in the 2nd gen forum that is a very big deal. Also it sounds like you have an air bubble in your coolant system. If you post in the second gen forum you will probably get more responses. I hope it is an easy fix

 

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