2011 Ram fan clutch diagnosis

[lmabey]

Any suggestions on diagnosing possible fan clutch issues on 2011 Ram 2500 6.7.

Should fan spin freely when key is off? Should fan spin freely when key is on but truck not started?

I am having two issues that have been suggested may be related to a bad fan clutch.

Issue one, weak AC at Idle when air temps are hot.

Issue two, when loaded with my cabover camper and the engine brake abruptly engages there is a sharp screech that then goes away.

Thanks for you input,

 

[Ozymandias]

Get yourself AlfaOBD and diagnose it.
It will tell you if it acts like it should, no other way to do so.

 

[Tuesdak]

Are you using "high idle" when the AC temps rise at idle? If it's at a stoplight IMO it's likely time to just replace the fan clutch. If it's over 5 years old you are not wasting money as they loose 200 RPM per year.

I find our fan clutches become slow to respond due to age: specifically they are spinning too slowly at idle to ramp up and lock in when the ECM asks them to. At idle you can check the fan RPM - it should be around 600 RPM kicked out. 400, 300, or less RPM it's toast. (Recall the fan pulley runs at a higher RPM then the crank pulley.) So if the fan clutch is slow to respond the AC performance suffers until you get enough airflow to cool the condenser.

You can read the fan RPM from the ECM or use an optical tach to check RPM.

 

[mweiman]

I would also suggest taking a good look at the radiator/cooling stack to make sure they are clean and getting good air flow.

 

[lmabey]

Get yourself AlfaOBD and diagnose it.
It will tell you if it acts like it should, no other way to do so.

So if i understand this AlfaOBD I download the app on the google play store and also need to purchase this interface from amazon.

Is this going to be self explanatory once its set up? or where can I find more info on running this AP?

 

[Ozymandias]

So if i understand this AlfaOBD I download the app on the google play store and also need to purchase this interface from amazon. View attachment 124731
Is this going to be self explanatory once its set up? or where can I find more info on running this AP?

Yes that's what you need, and yes it's more or less self explaining.
If you have difficulties ask here in the forum, we have people here that are really great using it for all and everything.

I also think that there are tutorials on youtube for AlfaOBD.