FLD120 low coolant temperature

Series 60 12.7 on its last leg. Oil in coolant. Couldn’t get above 130-140 while driving. At idle it would be 85-100. Obviously low heat and no heat with those temps. Changes thermostats today and idled for three hours. Temps at 160 and nice heat. Drove 28 miles to shipper and at high idle already down to 119.

I’m by no means a mechanic or understanding of most things. What am I missing? Is there too much oil in coolant for thermostats to work? Not sure if that even makes sense. Anything else I can so or fix to make this last two more weeks when new engine comes in? Oil cooler maybe?

 

Engine uses 2-3 gallons of coolant a week. At least 2 gallons of oil. Fuel mileage is garbage as well. Still making lots of money but tired of wasting fluids and money.

 

My new engine is being built. I’m just trying to have heat for another week or two till the engine is done.

My temps are fine going down the road and I have heat. idle between 1100-1400 RPM the temp was between 114-119 last night with outdoor temp of 20-25.

The thermostat replacement fixed half of the problem as I have heat and good water temp when going down the road. I just was looking for a solution to the idle temps so I can have heat while sitting/sleeping.

 

Already did that lol. Maybe Its not adequate??