Clutch Fan Running when engine is cold

[Big_Horn]

I have an 06, and this year I have noticed that the clutch fan is engaged when I feel it shouldn't. The other day, first start up engine temp showing 60 degrees (ambient temp) and it engaged, no load, even at idle. I hear it disengage after traveling a little but then it kicks on at lower speeds. No performance reduction, no coolant temp increases higher than normal operating temp. I have read lots of issues that the fan is not engaging, but in this case it seems as though it is on when it shouldn't. Any ideas??

 

[Hoefler]

Engaging for the A/C

 

[cerberusiam]

It will engage on startup until the viscous fluid warms and the ECM takes over controlling it, engine has to be running and at operating temp for it all to work like it should.

 

[AH64ID]

Did you scan for codes?

Often fan codes won’t set a CEL.

The fan clutch is ECM controlled so it could be a bad temp/pressure sensor of it could be normal.

 

[Big_Horn]

No codes. What is confusing for me is that I have had this truck since day 1. It has never acted like this till this year. Obviously there is a temperature sensor that controls the clutch. I am wondering if this sensor is going bad. I do not know what sensor it uses though. build it the hub unit of the clutch, engine temp or ambient temp sensors. Engine temp sensor and the ambient temp. sensor appear to be working normally.

 

[AH64ID]

There are lots of sensors it uses, to include ambient air, coolant, intake air, a/c pressure, etc.

The ambient air temp on the overhead isn’t the sensor it uses for the fan.

 

[Joe Hatfield]

No codes. What is confusing for me is that I have had this truck since day 1. It has never acted like this till this year. Obviously there is a temperature sensor that controls the clutch. I am wondering if this sensor is going bad. I do not know what sensor it uses though. build it the hub unit of the clutch, engine temp or ambient temp sensors. Engine temp sensor and the ambient temp. sensor appear to be working normally.

did you ever find a cure for this problem. my 2003 with 400,000+ miles has started doing the same thing. new hub installed 6 months ago. fan will come on at odd temps (i.e on at 160/170 off at 180/190 ect) ac has no effect on this condition. I have owned since new and it has never done this before. no codes show up

 

[Tuesdak]

Any fan clutch that is over 5 years old is "worn out". They loose 200 RPM per year and at some point they are "slow" to respond to RPM change requests: either too late turning on or off. Further they may not have enough RPM at idle to even lock up until you raise the engine RPM. IMO anything under 600 FAN RPM at idle when unlocked is worn out.

First start of the day the fan is generally on due to morning sickness: the working fluid has moved in the clutch while off and locks it up. Takes awhile for it to warm up and move out of the working chamber to unlock the clutch.

The 2003 has to have a hard failure to code. It likes to ignore worn out or lazy to respond clutches. The useless test is 15 min at "full on" to "do something". The AC has blown up and the engine melted down in that amount of time...

 

[Big_Horn]

did you ever find a cure for this problem. my 2003 with 400,000+ miles has started doing the same thing. new hub installed 6 months ago. fan will come on at odd temps (i.e on at 160/170 off at 180/190 ect) ac has no effect on this condition. I have owned since new and it has never done this before. no codes show up

No I never figured the issue out. Fan clutch is new. I know the fan will kick on with AC and Defrost in use nearly constantly. Only kicks off when at around 40-50 mph or when there is enough air passing through the condenser. I wonder if I still have a malignant AC issue.