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I regularly pull 8% grades in the Big Horn Mtns. here in WY and The Black Hills of South Dakota. I have put on over 5000 miles this summer on my 5er and truck. My aux fans come on at 240 degrees oil temp. The highest temp I have seen is 249 degrees. The fans do a good job of dropping the temps. Also, it's a good reminder when they come on that just because the truck will pull 18,000+ pounds up a hill at 50 mph, doesn't mean you should do it. It sure is fun tho. I do wish I knew how hot the coolant was, too.
... just because the truck will pull 18,000+ pounds up a hill at 50 mph, doesn't mean you should do it. It sure is fun tho. I do wish I knew how hot the coolant was, too.
I disagree...you won't hurt a thing. The fan is completely computer controlled on these engines, and the reason it doesn't come on before this is to protect your fuel economy and power delivery. Before your truck gets warm enough to risk damage the engine will de-rate to protect itself.
The truck has sensors for oil temp, coolant temp, tranny temp, exhaust temp, and secondary coolant temp. This is so the PCM knows how to run the truck most efficiently and safely....you will not hurt it by pulling something up a hill as fast as possible. This is why it's only rated at 400/800 instead of the 600/XXX tuned trucks are capable of; this is how much power can be produced safely.
But then again, I'm one to push limits...I have never modified a vehicle, but my Mustang sees it's 6,750 RPM redline every time it gets driven!
I disagree...you won't hurt a thing. The fan is completely computer controlled on these engines, and the reason it doesn't come on before this is to protect your fuel economy and power delivery. Before your truck gets warm enough to risk damage the engine will de-rate to protect itself.
The truck has sensors for oil temp, coolant temp, tranny temp, exhaust temp, and secondary coolant temp. This is so the PCM knows how to run the truck most efficiently and safely....you will not hurt it by pulling something up a hill as fast as possible. This is why it's only rated at 400/800 instead of the 600/XXX tuned trucks are capable of; this is how much power can be produced safely.
But then again, I'm one to push limits...I have never modified a vehicle, but my Mustang sees it's 6,750 RPM redline every time it gets driven!
Oh, trust me. I keep my foot in it. I just wish I could see the engine temp. I don't plan on letting up anytime soon. It's a kick in pants. I love towing my 5er up them hills.
I used to own a 1970 Boss 302. Orange/Black. 7200 rpm was my top effort. The little pony never missed a beat. Sure do miss that little filly.