Cummins ISX Still Overheating

I have a similar issue. I just changed the thermostat last night. It only has one that I could find. It’s still
Over heating. It runs between 215-225. It does seem to cool down after a steep pull or if the driver gears down a couple gears, it seems to run just fine. Water pump is
My next guess. .....

 

I would be having a look at the oil cooler. Those engines run near volcanic oil temps at the best of times. If the oil cooler is in any way compromised it can only drive the water temp up.

 

Here is a funny take on the over heating issues. A friend of mine was assigned a different truck by my company. They told him, "This truck always runs hot. You need to back out of full throttle pulling hills."

So he starts pulling loads with it, sure enough it runs hot. He took a 98K gross load up CA-62 from I-10 to get to Twenty Nine Palms. I was following him with the same load. He had to get down into first gear to pull the 8% grades. By comparison, with the same engine I would normally be about 30 mph.

He complained and took it to our shop in Fontana, then later to our main shop in Lodi. The replaced thermostats. Flushed the radiator. Did a number of things, but the issue persisted. It got to the point dispatch didn't dare send him too far, in case it broke down.

Meanwhile TWO oversized banners on the front bumper got sucked up into the radiator area on two consecutive oversized loads. He bungled the #### out of the second one and it still got sucked up into the radiator area.

Then one of the mechanics noticed something peculiar.

His fan was installed backwards.

Yep. Let me say it again.

The fan was installed backwards.

It had apparently been driven for YEARS like that. "Oh, it just runs hot. You need to learn how to drive it."

With the fan pushing air FORWARD the radiator wasn't getting cooled AND oversized banners got sucked into the vortex. Turn the fan around so it draws air through the radiator and just like magic, it can pull hills like a champ without overheating.

Simple solution. Lots of parts and shop labor later.

 

I've had to read that last part 3 times ...'the fan was installed backwards' ...wtf ...I've heard of air filters being installed backwards but fans ...wtf ...

 

Yeah, just got off the phone with my friend. Looking back on it there were tell tale signs, like when six of us ran 10 miles of dusty dirt roads in 100°F temperatures. All of us had the engine fan kicking up a dust storm, except for his truck.

 

Fan installed backwards does not make it push air. It will still suck, just alot less efficient because of the curve of the blades. To make a fan blow the opposite way, the pitch of the blades needs to be changed.

 

The physics of it all is beyond my pea brain warranty.

Yesterday I spoke with the mechanic that discovered the fan was installed backwards. He had no idea how long it had been that way, but documentation of driver complaints of overheating go back for a long time, well before my friend was assigned the truck last Fall.

Now that the fan is installed correctly, the truck runs great. No over heating. Pulls like a champ, like the rest of the fleet. The truck now has a new radiator, thermostat, etc. All that work could have been avoided if someone had the fore knowledge to look at the fan blades.

Seems like a good idea for anyone with chronic overheating issues to check the fan blade. That would be a cheap and easy fix, before diving down the expensive rabbit hole.