Fan noise coming from engine bay
#1
Thread Starter
Junior Member
Joined: Oct 2019
Posts: 35
Likes: 3
From: Langley BC
Year: 1989
Model: Comanche (MJ)
Engine: 4.0 L
Fan noise coming from engine bay
Hey y'all. So my cherokee has started acting funny in the cold weather, and I've noticed this strange fan noise that I haven't heard before. It comes on every 10 seconds or so and is pretty loud. Looked everywhere but cany find a video of something similar. Any ideas?
https://youtu.be/P8dXxVVboWw
https://youtu.be/P8dXxVVboWw
#3
Thread Starter
Junior Member
Joined: Oct 2019
Posts: 35
Likes: 3
From: Langley BC
Year: 1989
Model: Comanche (MJ)
Engine: 4.0 L
I guess that's what I'm talking about then lol. It comes on pretty frequently. What exactly does it do? I'm pretty new to this car stuff so I'm just learning all this.
#4
In cooler weather, compressor will go on and off more frequently. Every time it comes on, the electric fan comes on to move air across the condenser. It's possible that the refrigerant is low, but if it wasn't cycling as frequently in hot weather then it's nothing to worry about. If the temp coming out of the vents is cold, then you're good and can just get check in the spring. Or get a set of gauges and learn how to check AC pressures.
https://www.amazon.com/OrionMotorTech-Diagnostic-Manifold-Freon-Refrigerants/dp/B07JLQTK9C/ref=sr_1_1_sspa?keywords=ac+gauge+set&qid=1573015427&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExWE9QWUdJWElYWEFVJmVuY3J5cHRlZElkPUEwMDg1NDMxMkFZOVI1NEo0UkI0QyZlbmNyeXB0ZWRBZElkPUEwMTU4NjIzMTBFMlBNUFU3QThNJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==
#5
Thread Starter
Junior Member
Joined: Oct 2019
Posts: 35
Likes: 3
From: Langley BC
Year: 1989
Model: Comanche (MJ)
Engine: 4.0 L
In cooler weather, compressor will go on and off more frequently. Every time it comes on, the electric fan comes on to move air across the condenser. It's possible that the refrigerant is low, but if it wasn't cycling as frequently in hot weather then it's nothing to worry about. If the temp coming out of the vents is cold, then you're good and can just get check in the spring. Or get a set of gauges and learn how to check AC pressures. https://www.amazon.com/OrionMotorTec...xpY2s9dHJ1ZQ==
#6
CF Veteran
Joined: Nov 2017
Posts: 3,700
Likes: 236
From: Groton, MA
Year: 1995
Model: Cherokee(XJ)
Engine: I6 4.0L
Just to step back.
The XJ uses two fans as part of the stock cooling system. A mechanical fan (using a temperature based clutch) and an electrical fan. They are pretty obvious which is which, but if you're really, really green, the mechanical is the one connected to the belt pulley with the big fins and the electrical is the other fan (driver's side on a regular U.S. XJ).
The mechanical fan will spin whenever the engine is on, but when it gets to a certain temp, it will lock the fan to the pulley and spin "stronger" - this usually happens at idle, heavy traffic, etc.
As mentioned the electric fan will kick on automatically whenever the A/C is engaged. The A/C is engaged at all the regular A/C settings (assuming the A/C is working) or on any "Defrost" setting. Otherwise, the electric fan will NOT normally run under normal operating conditions.
The reason for this is the operating temp for the XJ is 205-210F. This looks like the needle a hair to the left of middle/center/210 label on the gauge when the engine is fully warmed up. The electric fan (outside of the aforementioned A/C stuff) will be triggered if the engine temp rises to roughly 220F as a backup.
It is normal to "hear" the e-fan kick on as you're describing when the A/C/Defrost is on. I also find the A/C compressor to be pretty loud on my 95. I had an older (orig probably) that was working but sounded like it was near failing so I replaced it with a new unit. Both the old and new are much louder than the compressor in my 2010 corolla which I can't hear at all from inside the car and barely from the outside and IIRC the compressor was loud on my last Jeep (an 00 TJ which had no e-fan).
If your refrigerant is low but not low enough to trigger the cut-off switch, it will cycle quite a bit on/off, but this is usually nothing to worry about.
So in short, I concur that you're fine - sounds normal to me.
The XJ uses two fans as part of the stock cooling system. A mechanical fan (using a temperature based clutch) and an electrical fan. They are pretty obvious which is which, but if you're really, really green, the mechanical is the one connected to the belt pulley with the big fins and the electrical is the other fan (driver's side on a regular U.S. XJ).
The mechanical fan will spin whenever the engine is on, but when it gets to a certain temp, it will lock the fan to the pulley and spin "stronger" - this usually happens at idle, heavy traffic, etc.
As mentioned the electric fan will kick on automatically whenever the A/C is engaged. The A/C is engaged at all the regular A/C settings (assuming the A/C is working) or on any "Defrost" setting. Otherwise, the electric fan will NOT normally run under normal operating conditions.
The reason for this is the operating temp for the XJ is 205-210F. This looks like the needle a hair to the left of middle/center/210 label on the gauge when the engine is fully warmed up. The electric fan (outside of the aforementioned A/C stuff) will be triggered if the engine temp rises to roughly 220F as a backup.
It is normal to "hear" the e-fan kick on as you're describing when the A/C/Defrost is on. I also find the A/C compressor to be pretty loud on my 95. I had an older (orig probably) that was working but sounded like it was near failing so I replaced it with a new unit. Both the old and new are much louder than the compressor in my 2010 corolla which I can't hear at all from inside the car and barely from the outside and IIRC the compressor was loud on my last Jeep (an 00 TJ which had no e-fan).
If your refrigerant is low but not low enough to trigger the cut-off switch, it will cycle quite a bit on/off, but this is usually nothing to worry about.
So in short, I concur that you're fine - sounds normal to me.
#7
Hey y'all. So my cherokee has started acting funny in the cold weather, and I've noticed this strange fan noise that I haven't heard before. It comes on every 10 seconds or so and is pretty loud. Looked everywhere but cany find a video of something similar. Any ideas?
https://youtu.be/P8dXxVVboWw
https://youtu.be/P8dXxVVboWw
Sorry to hear of the trouble you are experiencing. I certainly understand why this would be concerning. If you are unable to determine the cause of this with the assistance of fellow forum members, I suggest connecting with your local certified Jeep dealer as they are in the best position to assist. Please know that we are available via private message if you are in need of any assistance with that process.
Laura
JeepCares
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