Fan clutch failure?

[Auger]

Hey all!

Seeking some advice regarding an issue with my 2017 Ram. Regardless of my coolant temperature, the mechanical fan locks. Its progressively gotten worse in the last month.

It starting coming on when I had the A/C on even if I was moving. Now, after 30 seconds of running the fan locks up and my truck sounds like a vacuum cleaner!

When the engine is off, I can turn the fan but there is definite resistance. I unplugged the connector going to the fan and the problem persists.

I thought the fan was controlled by the truck, but it looks like it is a simple clutch failure.

Anybody have experience with diagnosing these or a theory of operation to help me better diagnose?

Truck has 39k miles. I don't want to shoot the parts cannon at the truck, and the clutch is over $300.

Thanks in advance,
Tom

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[InlineSix.7]

Tom, the fan operation is intentionally more aggressive when the AC is turned on so that additional air is pulled across the condenser. Without that, the performance of the AC would tank when you were parked and/or in stop and go traffic. Even with a cold engine and the AC turned off the fan will be spinning whenever the engine is running. When the engine is turned off it is also normal to feel resistance when turning the fan by hand. I just replaced the fan clutch on my 2012 a few weeks ago because the AC was going hot when the truck wasn't moving. I'd speculate that with as new a truck as you have it's not likely the fan clutch has gone bad. I'm no expert on the matter but if you can tell a difference in noise/fan operation when you turn on/off the AC I'd say that it's working properly. These are just big engines with equally large fans that make a lot of noise. The newer Cummins engines are just so quiet you can hear things like engine fans. Whenever my 2001 was running with the hood up I always felt like I needed ear plugs from all of the diesel rattle

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[Polaraco]

Hey all!

Seeking some advice regarding an issue with my 2017 Ram. Regardless of my coolant temperature, the mechanical fan locks. Its progressively gotten worse in the last month.

It starting coming on when I had the A/C on even if I was moving. Now, after 30 seconds of running the fan locks up and my truck sounds like a vacuum cleaner!

When the engine is off, I can turn the fan but there is definite resistance. I unplugged the connector going to the fan and the problem persists.

I thought the fan was controlled by the truck, but it looks like it is a simple clutch failure.

Anybody have experience with diagnosing these or a theory of operation to help me better diagnose?

Truck has 39k miles. I don't want to shoot the parts cannon at the truck, and the clutch is over $300.

Thanks in advance,
Tom

Tom, the fan operation is intentionally more aggressive when the AC is turned on so that additional air is pulled across the condenser. Without that, the performance of the AC would tank when you were parked and/or in stop and go traffic. Even with a cold engine and the AC turned off the fan will be spinning whenever the engine is running. When the engine is turned off it is also normal to feel resistance when turning the fan by hand. I just replaced the fan clutch on my 2012 a few weeks ago because the AC was going hot when the truck wasn't moving. I'd speculate that with as new a truck as you have it's not likely the fan clutch has gone bad. I'm no expert on the matter but if you can tell a difference in noise/fan operation when you turn on/off the AC I'd say that it's working properly. These are just big engines with equally large fans that make a lot of noise. The newer Cummins engines are just so quiet you can hear things like engine fans. Whenever my 2001 was running with the hood up I always felt like I needed ear plugs from all of the diesel rattle

That's good info inline.

Those fans are made to default to engaged when they are failing. They are electrically controlled by the ECM. The control is based on the AC function and engine temp. I'm pretty sure there is a temp sensor in the fan to read the rad temp before the engine temp is considered. Don't quote me on that. 1st gens had a bimetal coil that controlled the fan clutch by the rad temps. Just like the older cars had.

In the past, I have seen a few where the wiring got loose and chafed through. On the 2nd and 3rd gens, there's a metal shield over the wiring. Not sure on the 4th gens. It runs up the left side of the Rad to the front of the engine behind the fan. There is a slip ring somewhere for the connections.

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