Quote:
Originally Posted by Diesel_Dave
I have a clutched fan on my truck. I believe the clutch is electrically controlled. I'm thinking I may be able to improve my FE by turning it off when it's not needed. An electricl fan is an option, however, if the clutch is electricallly controlled, I should be able to just use that to control the fan better (which should be more efficient than an electric fan). Before I do anything, however, I want the check and see how often the fan is running "unnecessarily" as it currently is.
It's a pretty quiet fan, so I can't hear it over the engine. Does anybody have any tips for a quick and dirty way to tell if the fan is running (while driving)?
|
The clutch is electrically controlled, both on/off and in percentage of torque application, IIRC; it's sophisticated, not simple. There are some decent threads on this subject on CTD boards related to failures due to the harness being cut by said fan, when:
Deep water fording
Regular hard off-road use
as it appears the radiator moves a bit in it's mounts (shock absorbtion?) and the harness flexes and is cut by the running fan. (May also be model year dependent).
This thread goes into cross-brand "fixes" and workarounds. Some interesting stuff to play with for those so inclined.
In big trucks we know that percentage of "on" time for mechanical fans is cited in the literature as detrimental to fuel economy. Some decent threads on big truck boards about this, also, including conversion to non-engine-driven fans (completely electrical) for Class 8. (Both on
Truckers Report and
CAD.)
There are some conversion
kits now for the CTD. I'm more than a little afraid of failure of cooling fans under tow, but others are not (see
here).
The SAE J2807 Towing Guideline utilizes the infamous Davis Dam grade in Arizona to determine limits. One of which is backing a trailer on a 12% incline at the GCWR. Stop and go. In summer.
Always worthy of keeping in mind, IMO, as one need not be in AZ, much less in summer temps, to overload a cooling system. Have seen PS systems fail -- in winter -- horsing a trailer around with no appreciable airflow. Trying to move a trailer around in a flood comes to mind. Etcetera.
.