I have replaced everything in my jeep to keep in cool during trail riding. On highway or in town in runs at190 degrees. Slow trail riding it runs at 220 degrees. I have new thermostat, water pump, fan clutch, additional electric fan, exhaust system, oil pump and screen, aluminum radiator, temp. Sensor, etc. Is 220 to high for trail riding with 4.2L?
normal operating temp. on 4.2
MCobb5
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I have replaced everything in my jeep to keep in cool during trail riding. On highway or in town in runs at190 degrees. Slow trail riding it runs at 220 degrees. I have new thermostat, water pump, fan clutch, additional electric fan, exhaust system, oil pump and screen, aluminum radiator, temp. Sensor, etc. Is 220 to high for trail riding with 4.2L?
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Yep, you are in range... A 4.2 isn't hot until you start approaching 240+. With an electric fan, and 3 core aluminum rad. I can keep it down as low as 180 with the fan running constant, but have the thermostat set to turn on at 215 and off at 195. A hotter engine is actually more fuel efficient to a point.
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It can run forever at 220f without causing any issues what so ever.
Dwayne
Dwayne
as long as it isn;t overheating, running warm is fine.
i have had vehicles run at 3/4 temp all day long.
220 only on the highway, in town its lower? have you cleaned the radiator out? sound like a dirty or clogged radiator.
if its hot around town but cool on the highway, its the fan clutch or something like that.
if its hot on the highway but cool around town, its the radiator.
both of those are most common, not absolutes
i have had vehicles run at 3/4 temp all day long.
220 only on the highway, in town its lower? have you cleaned the radiator out? sound like a dirty or clogged radiator.
if its hot around town but cool on the highway, its the fan clutch or something like that.
if its hot on the highway but cool around town, its the radiator.
both of those are most common, not absolutes
Thanks for the reply. It has a new 3 core radiator, new flowkooler waterpump ( the correct one for serpentine belt) new hoses and heater core and the engine is fresh rebuild with 6000 miles. I have a smittybilt xrc front bumper with a 9500 lb. Winch. This blocks about half of airflow or disrupts it enough that it won't cool at 70-75 mph like it should. If I stay at 60-65 it runs about 180-190. I think I'm going to try some hood louvers and see if that will allow more airflow. What say yall?
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Just a heads up!!! I'm in the process of changing out my engine and some other work. I had a post on here a year or two ago about it running hot on the highway and just figured out what was going on when I went to pull the engine. Somebody changed out the fan on my old engine and it had reversed blades compared to the engine that I picked up. Both engines are v-belt regular rotation, not reverse rotation. Explains why around town it didn't heat up but at highway speeds it would shoot up. The faster I went the warmer it would get. Stupid POs!:gunfight:
its easy to tell if you have the right fan on it. as the engine is turning off, watch the fan. the leading edge of the fan blade should be the side closest to the radiator. the leading edge lets the blade pull so as long as the closest side is the side going whatever direction the fan is turning, it will pull air in.
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Running them cool is BAD.
They make the most power and get the best fuel milage when run at the factory determined temps. 220f all day long.
Dwayne
They make the most power and get the best fuel milage when run at the factory determined temps. 220f all day long.
Dwayne
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To add to the fan clutch theory, mine was running hot at idle all day long and as soon as I'd hit 20 mph the temps would drop so I replaced the fan clutch and all is well. Hopefully someone sees this for future reference.
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I'll agree with you to a degree. (pun intended)
The difference between a 195 and a 220 isn't enough to make a dramatic drop in performance, yet keeps the engine cooler on the trails. Now, dropping to a 180 or a 165? Yeah, no bueno.
My mechanic (ASE Certified Master Mechanic for over 20 years) and I talked about this at length and the consensus was --- if it's going to be on the road most of it's life, go stock 220. If it's going to be trail riding with lots of strain and tons of idling, drop to 195, but no further.
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This is my normal operating temperature at high idle mid 20s outside temperature
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