- Joined
- May 11, 2016
- Posts
- 219
- Reaction score
- 338
- Location
- North Carolina
- Ram Year
- 2017
- Engine
- 5.7 Hemi
OEM's use hotter T-stats primarily because a hotter running engine yields better emissions performance. How much cleaner is unknown. A hotter running engine will push engine oil temps higher as well. That issue gets compounded if one tows in hot weather. Coolant and oil temps can climb quite high. Engines generally make the most power with relatively cool water and relatively hot oil. Engine coolant in the 185 to 195 degree range, and oil temps between 180 and 220 degrees.
Installing a 180 degree T-stat will have coolant temps stabilizing in the 185 - 186 range while moving at speed. On an untuned truck, you do want coolant temps to initially reach at least 186 because if it stays cooler than that, a code may be thrown. Also on an untuned truck, sitting in stopped traffic will still have coolant temps climb into the 190's and possibly into the 200's as your e-fan doesn't turn on until coolant temps climb into the 220 degree range. Some have reported issues with the hemi shutters fighting the 180 T-stat. The shutters allegedly are for better aerodynamics, but in fact they do restrict air flow thru the radiator & trans cooler to a degree. The entire assembly can be removed if desired by performing one of two tweaks to the motor that drives the shutters. Search this forum, as there are posts describing both methods. My shutters have been removed for over 15K miles with no issues.
Some have said that motor oil can safely take consistent temps in the 230 degree range or higher. Perhaps, but motor oil is rated at 100 degrees C, or 212 F for hot running performance. Higher temps than that will cause the oil to thin, not perform as a 20 weight, if you are running 5W-20, or perform as a 30 weight, if you are running a 5W-30 as examples. The higher the temps go, the more the oil thins, and the less effective the oil is at reducing wear.
In my truck, the 180 T-stat has my coolant stabilizing at 186 degrees while underway, and my oil temps in the 203 degree range. Aggressive driving, or climbing a grade while towing my enclosed cargo trailer will force those a bit higher, but still ok. I'm happy running the 180 degree T-stat in my truck.
Installing a 180 degree T-stat will have coolant temps stabilizing in the 185 - 186 range while moving at speed. On an untuned truck, you do want coolant temps to initially reach at least 186 because if it stays cooler than that, a code may be thrown. Also on an untuned truck, sitting in stopped traffic will still have coolant temps climb into the 190's and possibly into the 200's as your e-fan doesn't turn on until coolant temps climb into the 220 degree range. Some have reported issues with the hemi shutters fighting the 180 T-stat. The shutters allegedly are for better aerodynamics, but in fact they do restrict air flow thru the radiator & trans cooler to a degree. The entire assembly can be removed if desired by performing one of two tweaks to the motor that drives the shutters. Search this forum, as there are posts describing both methods. My shutters have been removed for over 15K miles with no issues.
Some have said that motor oil can safely take consistent temps in the 230 degree range or higher. Perhaps, but motor oil is rated at 100 degrees C, or 212 F for hot running performance. Higher temps than that will cause the oil to thin, not perform as a 20 weight, if you are running 5W-20, or perform as a 30 weight, if you are running a 5W-30 as examples. The higher the temps go, the more the oil thins, and the less effective the oil is at reducing wear.
In my truck, the 180 T-stat has my coolant stabilizing at 186 degrees while underway, and my oil temps in the 203 degree range. Aggressive driving, or climbing a grade while towing my enclosed cargo trailer will force those a bit higher, but still ok. I'm happy running the 180 degree T-stat in my truck.
