Fan speed sensor
Thread Starter
|
Laughing Gas
Joined: Jan 2012
Posts: 1,103
Likes: 1
From: Lakeland, TN
Fan speed sensor
2003 F250 6.0 and my FSS on the Scan Gauge now sits at zero constantly. Additionally, the fan speed runs right along RPMs. Hold a constant speed on the interstate and get a constant fan speed until you let off. Engine temp has nothing to do with it. It goes that way right from the initial start up, when all the temps are air temp. I figure the sensor is bad so it just runs based on some other control system, which seems to be the throttle. Is that about right? Is this a DIY repair project? What part needs to be replaced? Thanks.
Postmaster
Joined: Nov 2015
Posts: 4,807
Likes: 125
From: Colorado Springs
2003 F250 6.0 and my FSS on the Scan Gauge now sits at zero constantly. Additionally, the fan speed runs right along RPMs. Hold a constant speed on the interstate and get a constant fan speed until you let off. Engine temp has nothing to do with it. It goes that way right from the initial start up, when all the temps are air temp. I figure the sensor is bad so it just runs based on some other control system, which seems to be the throttle. Is that about right? Is this a DIY repair project? What part needs to be replaced? Thanks.
Thread Starter
|
Laughing Gas
Joined: Jan 2012
Posts: 1,103
Likes: 1
From: Lakeland, TN
I did an Electric Fan swap on my Jeep. The fan needs to get a reading of the coolant whether it’s a probe through the radiator or sensor. I got tired of the probe style thermostat and went with a VSS, variable speed sensor that is plumbed in the top radiator hose. Sounds like you need to figure out where the sensor is located and either replace it or improve its ability to read the engine temperature. The fan should NOT run of vehicle speed but rather engine temperature...
Thread Starter
|
Laughing Gas
Joined: Jan 2012
Posts: 1,103
Likes: 1
From: Lakeland, TN
Does the mechanical version just run at a constant speed? If not, what controls it? If it’s RPM, well, I've already got that. 😏
Mountain Pass
Joined: Apr 2016
Posts: 212
Likes: 46
From: North Dallas
Thermal Fan Clutches operate in response to underhood temperatures. When the engine is cold, the fan is disconnected; when too much heat is generated, the fan is allowed to cool the engine. A bi-metal thermostatic coil mounted at the front of the clutch senses the underhood temperature and operates the clutch accordingly.
Thread Starter
|
Laughing Gas
Joined: Jan 2012
Posts: 1,103
Likes: 1
From: Lakeland, TN
Here it is direct from the manufactuer Hayden.
Thermal Fan Clutches operate in response to underhood temperatures. When the engine is cold, the fan is disconnected; when too much heat is generated, the fan is allowed to cool the engine. A bi-metal thermostatic coil mounted at the front of the clutch senses the underhood temperature and operates the clutch accordingly.
Thermal Fan Clutches operate in response to underhood temperatures. When the engine is cold, the fan is disconnected; when too much heat is generated, the fan is allowed to cool the engine. A bi-metal thermostatic coil mounted at the front of the clutch senses the underhood temperature and operates the clutch accordingly.
Trending Topics
Mountain Pass
Joined: Apr 2016
Posts: 212
Likes: 46
From: North Dallas
That sounds better than what I have. I noticed that mine no longer speeds up based on rising temperatures and does not do a particularly good job of cooling. I have the Mishimoto (sp?) thermostat and typically run 206-210 degrees. It used to really fire up at 210 and blow it back down to about 204. Now it just sits at 210. I wonder what it would do if I was pulling my Bobcat? I suspect the temps would rise further and the fan would not react. Does the mechanical motor have the ability to go up around 3000 RPM like the stock one? I’m guessing the Scan Gauge will no longer record a fan speed, as it’s no longer computer controlled.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Fords at 2026 Carlisle Ford Nationals
Joe Kucinski
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Thread Starter
|
Laughing Gas
Joined: Jan 2012
Posts: 1,103
Likes: 1
From: Lakeland, TN
Scangauge will not see a mechanical fan. The mechanical fan has some huge side benefits at engine idle the fan is engaged and pulling air in, at 2000-2200 rpm the fan disengages so in stop and go traffic you are getting better cooling and it help AC system run cooler to. When you heat it up and the thermostat in the fan engages and locks to the engine rpm it moves a lot of air and I mean a lot. The mechanical fan was 1 of the best upgrades I did on my psd.
Thread
Thread Starter
Forum
Replies
Last Post