.....This Fan Mod is NOT recommended for the M3 cars!.....
- Mechanical Fan to Electric Fan DIY -
I have an auto, and our cars come with a Mechanical Fan (engine driven) as well as an Auxiliary Fan to help with A/C and extra cooling power. I found a couple threads, but no real answers. I finally decided to PM the almighty and infinitely knowledgeable Mr. Nick G @ Technique Tuning, who informed me that it is a direct swap, and he performs this swap on his steptronic cars with no problems. The Mechanical Fan and the Auxiliary Fan have both been removed on my car, and replaced with a single OEM Electric Fan. So far so good. No wiring, no fitment issues, nada. Plops right in, plugs right in, and works.
The electric cooling fan is controlled by the ECM. The ECM uses a remote power output
final stage (mounted on the fan housing). The power output stage receives power from a
50 amp fuse (E46 - located in glove box above the fuse bracket). The electric fan is controlled
by a pulse width modulated signal from the ECM.
The fan is activated based on the ECM calculation (sensing ratio) of:
• Coolant outlet temperature
• Calculated (by the ECM) catalyst temperature
• Vehicle speed
• Battery voltage
• Air Conditioning pressure (calculated by IHKA and sent via the K-Bus to the ECM)
After the initial test has been performed, the fan is brought up to the specified operating
speed. At 10% (sensing ratio) the fan runs at 1/3 speed. At a sensing ratio of between 90-
95% the fan is running at maximum speed. Below 10% or above 95% the fan is stationary.
The sensing ratio is suppressed by a hysteresis function, this prevents speed fluctuation.
When the A/C is switched on, the electric fan is not immediately activated.
It is run from 10 HZ to 100HZ a scope is the best way to see the signal. You can command the fan by creating a signal or using the RIGHT scan tool you can tell what speed you want it to run at and measure the HZ with a scope therfore checking you DME output.
- Direct Link to E46fanatics DIY -
All you need is is this:
Floor jack and one jack stand
8mm socket or 8mm wrench
Fan clutch tools
OEM electric fan: 17117561757 & 351038391
51118174185 (as many as your break)
51471919209 (as many as your break)
- Front Bumper Removal DIY -
Car up on ramps is recommended.
- Remove the 8mm bolts holding bumper to the fender liners.
- Take out the reinforcement bolts with 9mm socket/ratchet/extension.
- Unclip wiring for fogs and horn, slide bumper out.
- Take out the top air intake.
- The center duct is held by four pop in screws (these 4 will likely break and need replaced).
- Aux fan is held by four 13mm nuts, take them out.
- Disconnect the aux fan by the fan shroud in the engine bay.
- Slide the fan out
- Put the center duct back in and top air intake.
- Put the front bumper back on in reverse order (slide in, put in the two reinforcement bar bolts and the assorted bolts to the liners).
- Next you have to take the mechanical fan out.
- Pop out the fan control unit on the shroud and the other wiring and put them to the side.
- Take out the 1 torx screw on the passenger side top and loosen up the fan shroud.
- Use the fan clutch tool to loosen the bolt and take out the assembly.
- Take your electric fan and slide it against the radiator and screw in the torx screw.
- Plug the electric fan to the connector where the aux fan was plugged into.
- Place back the control unit and the other wiring to the electric fan shroud.
- E46 Cooling Fans Explained -
A. The MECHANICAL FAN sits naked inside the engine bay and hangs off the engine block. It is always on from the minute you turn the key to start the engine. It stays on all the time until the engine is turned off. It always spin at the same speed coinciding with the belt drive system. It is attached to engine via the water pump and is also connected with the belt drive system. This fan directly cools the engine and is usually quiet. This is the fan that tends to explode from a bad water pump bearing (i.e infamous water pump wobble) or cracked blades. This fan is driven by the belts in the belt drive system which means that this fan will NOT work if the belt drive system pulley components seize up, engine belts break or alternator seizes.
The belt drive system also includes as shown in the picture Below the power steering pump (D), idler and tension pulleys (respectively C and B), alternator (I) water pump pulley (A) and AC compressor (F).
Although the Mechanical Fan is connected to the same belt drive system that the AC Compressor is connected to the Mechanical Fan has nothing to do with AC coldness or strength. However the reverse is sort of true. When the AC is turned on in the cabin the effect of the AC compressor turning on is rippled thru the belt drive system and will be demonstrated as a momentary roughness in the engine rpm (i.e the rpm needle on the odometer jumps).
B. The AUXILIARY FAN sits in a plastic enclosure outside the engine bay. It is located in front of the radiator right behind the nose panel's kidney grills where it can be seen thru from the outside whiles looking thru the grills at the front of the car.
This fan is usually off for the most part and only turns on for brief intervals at a time to assist in extra cooling during times of high engine load and hot weather engine idle especially during congested summer traffic.
This fan primarily enhances cooling to the radiator zone by pushing cool air into the engine from outside the kidney grills.
Because of its location the Auxiliary Fan does not directly cool the engine block the way the Mechanical Fan does.
The Auxiliary fan when it comes on can be super loud (ie. the infamous UPS/FedEx Truck sound) and annoying.
This fan is not attached to belt drive system and can still work if the belt drive system fails. However, it is an electrical powered fan and depends on the alternator and battery for power.
The Auxiliary fan has absolutely nothing to do with enhancing the AC Compressor or AC coldness/strength as felt inside the cabin. However the reverse is true as when the AC Compressor/AC is on during engine idling this fan will come on only to assist in extra cooling to the radiator and engine bay.
Because the steptronic transmission's cooling lines run to the radiator this fan is thought of to also enhance transmission cooling on steptronic/automatic cars.
C. The ELECTRIC FAN as it relates to the E46 originates ONLY in manual transmission cars (except M3) from 1998 to 2006. The Electric Fan has now also permanently replaced the Mechanical Fan as the sole main engine cooling fan on all modern era BMW cars from 2005/2006 to present.
On the E46 this fan sits in a plastic enclosure inside the engine bay between the back of the radiator and empty space in front of the engine. It cannot be seen from outside the car thru the kidney grills and it works to "pull in" cool air from the front of the car into the engine bay. This fan is usually always quiet and on.
The ELECTRICAL FAN, on the manual cars, can be said to replace both the MECHANICAL FAN and AUXILIARY FAN by directly cooling both the radiator and engine bay zones. So one electrical fan in theory will provide the same cooling performance as the Mechanical Fan and Auxiliary Fan.This fan is not attached to belt drive system and can still work if the belt drive system fails. However, it is an electrical powered fan and depends on the alternator and battery for power.
NOTE ABOUT THE FAN DELETE MOD: This should really be called the "One for Two Fan replacement mod" because at the end of the mod your steptronic/automatic E46 car will have the exact one Electric Fan set up that the manual cars all have.
When done correctly the Electric Fan has been successfully transplanted to replace both the original Mechanical & Auxiliary Fans on steptronic/automatic E46 vehicles.
It is important to understand that for the Electrical Fan to work properly both the original Mechanical & Auxiliary Fans MUST first be removed, or deleted, from the car.
When said and done the newly installed Electrical Fan will use the same connector that the Auxiliary Fan uses and, because it is mounted on the inside of radiator support frame, the Electrical Fan will sit in the same engine bay space that the Mechanical Fan occupied before the modification.
Although disputable, the swap is said to alleviate the weight burden and parasitic drag* that the Mechanical Fan puts on the the belt drive system and water pump. This lack of weight is said to improve MPGs and add performance in HP. Removal of the Auxiliary Fan is said to make the car run quieter and smoother.
Engine cooling/performance, transmission cooling/performance as well as in cabin AC cooling is not affected in anyway by the removal of the two fans and the swapping in of the one Electrical Fan. *
Said and done, the hard fact remains that the one Electrical Fan actually can replace both the Mechanical Fan and Auxiliary Fan on the steptronic automatic e46 cars.
Cooling System Maintenance
BEHR/BOSCH Fan #17-11-7-561-757-M14 and #351038391
- Click on the Vendors below for direct link to order! -
Water Pump Thread Cap/Nut
MECHANICAL vs. ELECTRICAL FAN
AUXILLARY FAN INSTALLED
AUXILLARY FAN REMOVED
- OBDII Digital Engine Temp Gauge with Alarm -
Doing this Mechanical Fan to Electric Fan swap was worth it in many ways. But I would really like to know exactly what my engine temp is just incase. The question is then what temperature should my engine run at? My temps seem to run consistently between 88-96C (190-205 ) starting to think 95C/203F is really the magic baseline after a bit more research. Around town my car seems to really like 92-95C lately. Currently trying to also figure out what a upper temperature threshold or baseline may be during the Summer outside temps pushing 100F. Have not confirmed upper temps yet, however, 100-105C may be not unusual for the peak Summer temperature? Driving on the freeway in 100 degree weather my car temp is consistently at 192 degrees (89C).
There many options to choose from ranging from $50-$500 depending what you are looking for. I wanted a OBDII Gauge that monitors the cooling temp and sets off a alarm if it gets too high. I liked the Coolant Snitch but it doesn't give a temp reading. Below are a few OBDII gauge monitors ranging in price starting with the lowest. I have the Edge CTS Insight in my Chevy Silverado 2500HD and love it, but it is kinda large for the BMW. So I decided on the UltraGauge which costs approx $70 shipped. So far I really love this little gauge! Here is a link to my review.
- Ultra Gauge - $70
* Supports all 1996 and newer OBD II compliant gas vehicles***
* Up to 75 selectable Gauges*
* Real time and long term mileage gauges
* Distance-To-Empty Gauge
* Displays 6 selectable gauges at once
* Displays 3 pages of gauges for a total of 18 quickly accessible gauges
* Auto-Page advance, cycles through gauge pages
* Configurable low and high alarms for every gauge
* Audible and Visual Alarms
* Alarms may be individually suspended.
* Displays both current and pending trouble codes
* Clear Check Engine Light and Trouble Codes
* Current and pending Trouble Code Alarms
* Automatic fuel fill-up detection **
* Oil change and Service Gauges
* Trip Gauges
* Health indicator
* Internal temperature sensor that can be monitored and alarmed
* Closed and open loop indicator.
* Large LCD Display
* Display Brightness adjusts automatically to ambient light
* Lightweight easy to route OBD II cable
* Compact and easily mounted with Velcro or optional windshield mount
* Low power
* Retains configuration and accumulated data across power cycles
* Automatically detects and turns off display when vehicle is off
* Comprehensive menu system
* Comprehensive detailed 43 page user manual
- CoolantSnitch - $90
In the video below, the OBC function 7 is unlocked with the coolant temperature readout displayed in degrees C (the digital output just above the ambient temperature display on the dashboard). The electric fan on the car has been disabled, allowing the temperature to rise above normal. At 2:40 the temperature reaches the triggering point of the device.
It is a well documented fact that the E46 generation of BMW 3-series vehicles is prone to a variety of cooling related issues. The frequent occurrence of these issues has forced many enthusiasts to preventively replace nearly all cooling related components at ~60K mile intervals. The true severity of the problem lies in the fact that the engine may overheat without any obvious signals, which ultimately leads to costly repairs.
The E46 Thermostat
Conventional thermostats are very basic devices. They are built to mechanically alter the path of coolant traveling through them depending on the temperature of the coolant. The E46 thermostat, however, is a bit more sophisticated. For the E46 models, BMW uses what is known as a “Characteristic Map Thermostat”. This means that the thermostat is built to allow, to some extent, the DME to alter the open/close temperature range. This approach is used mainly to conserve fuel efficiency. Under partial loads, better fuel economy may be achieved if the coolant temperature is raised up to 110 degrees C. Under heavy loads, this temperature may cause engine knock and, as a result, the DME lowers the opening temperature of the thermostat via an electrical connection, allowing cooler running temperatures. By BMW's specifications, the normal operating range for the engines fitted on the E46 is between 75 - 113 degrees C.
The E46 Temperature Gauge
Ever wonder how is it that the coolant temperature on the E46 dashboard manages to stay at the same mark no matter how hot or cold the ambient temperature is, or how hard you may have been driving the car? This is because the temperature reference on the E46 models is "fake"... well, to some degree (no pun intended!). Because BMW utilizes the Characteristic Map Thermostat described above, the actual coolant temperature may vary by as much as 40 degrees under normal driving conditions. As a result, a true gauge would look somewhat sporadic, which could cause an excessive number of calls to the service department. To eliminate this problem, the gauges on the E46 dashboard have been given some "intelligence". For temperatures up to 75 degrees C, the gauge displays the "real" temperature. When it displays the actual read out, the 1st notch after the blue bar indicates roughly 65 degrees C. When the coolant temperature reaches 75 degrees C, the needle is moves to the upright 12 o'clock position. The needle will remain at this position until the coolant reaches a temrperature of 113 degrees C . At this point the needle will start to move upwards, reaching the 3/4 notch at ~120 degrees C.
While this may seem like a reasonable approach, it has one major downside. If the coolant temperature in the car is rising due to an actual malfunction, the driver has absolutely no indication of this until 113 degrees C is reached. Furthermore, subtle movements of the needle are hard to notice, so if the temperature is climbing quickly, it doesn’t take much time at all to reach the red zone.
We have been working on a solution to help E46 enthusiasts to save their engines by providing a preemptive warning before the temperatures are too high. Meet project CoolantSnitch(tm). This simple device is built to operate with the existing BMW coolant temperature sensor and provides constant monitoring of the input signal. When the coolant temperature reaches a critical mark of ~117 degress C, CoolantSnitch(tm) will sound an alarm to help the driver identify the problem while the temperature is still within a non-critical range.
CoolantSnitch(tm) is connected to the DME using 3 T-Tap connectors. The 2 connectors supply +12V and Ground, while the 3rd one is connected to the coolant signal line. The device has very high impedance (~1.5 TOhms) which makes is invisible to the DME and causes no interfiereince with the operation of the stock subsystem.
CoolantSnitch has been tested and approved for the following BMW models.
DME VersionModelProduction date.
MS45.1E46 330i/Ci/Cic03/2003 and up
E46 325i/Ci/Cic03/2003 and up
MS43E46 330i/Ci/Cicbefore 03/2003
E46 325i/Ci/Cicbefore 03/2003
- ScanGauge - $170
Advanced, Ultra-compact Vehicle Monitor
ScanGaugeII can help you monitor your vehicle’s most vital systems and provide the kind of real-time information you’ve been missing. Features include more than 15 built-in digital gauges, 5 sets of trip data and an easy-to-use ScanTool that shows both set and pending trouble codes — All in an ultra compact design that installs in minutes.
Exclusive Programmable Gauge System
The ScanGaugeII features the exclusive X-GAUGE™ programmable gauge system; you can monitor parameters such as transmission temperatures†, trip data and fuel economy information. X-Gauge™ gives you the ability to customize your ScanGaugeII by adding additional vehicle specific digital gauges.
All New Performance Monitor
The ScanGaugeII features the all new Performance Monitor™ for real-time performance measurements. The Performance Monitor gives your the ability to track your vehicles performance over short periods of time, distance and acceleration.
Learn to Improve Your Gas Mileage
The US government has put out a report that says driving habits can change fuel-economy by up to 33%. ScanGaugeII provides real-time data about your vehicle’s instant and average fuel economy, fuel used, cost of fuel used for each trip, cost per mile, gallons per hour and more!
Trouble-shoot Your Vehicle
ScanGaugeII can help you diagnose and trouble-shoot problems by providing real-time data about your vehicle’s performance. In addition, ScanGaugeII will display captured trouble codes and conditions when the problem occurred. With the ScanGaugeII you can “pull the codes”, make your own repairs and turn off warning lamps just like the Pros.
Catch Problems Early
ScanGaugeII provides real-time gauges to show you what is going on “under the hood” so you can catch issues early before they become more expensive problems.
Clear Trouble Codes
Data captured when the Trouble Code was set can be recalled to help troubleshoot the problems (was the temperature hot or cold, speed high or low, etc.). The ScanGauge II can be used to clear the trouble codes and data which will turn off the warning lamp.
The ScanGaugeII can check for Diagnostic Trouble Codes (DTCs) and if found, can display how many there are and the Trouble Codes themselves. Using the internet or repair manuals, these can be translated to the failed component and repairs can be made.
Is Your Vehicle Ready for Emissions Testing?
Some states now require that vehicle self tests have been completed since the codes were last cleared, before running emissions checks. The ScanGauge reports this “Readiness”.
Read & Clear Pending Trouble Codes
If no codes where found and your Check Engine light is still on, your vehicle may be storing pending codes. ScanGauge provides a method to force clear any detected or undetected Trouble Codes.
- Edge Insight CS & CTS - $300 & 400
Edge Products presents the new Insight CTS. With unmatched control and style, the all-new Insight CTS offers the most advanced technology in engine monitoring available today. The Insight CTS is compatible with any OBDII-enabled vehicle 1996 and newer.
The Insight CTS offer many of the same great features and benefits users have come to expect from Edge Products, along with a whole host of exciting additional features.
•Available for 1996 and newer vehicles equipped with an OBDII (diagnostic)port
•Full-color, high-resolution, 4.3 inch touch screen
•Displays available SAE data from your vehicle’s computer*
•Data parameters (PIDs) on CTS products will vary by vehicle year, make, and model.
•View parameters in numeric or analog style gauge display
•Digital gauge display/scan tool (does not reprogram/tune the vehicle or add power)
•Compatible with optional EGT pyrometer for engine protection ( view accessories by clicking here)
•Compatible with optional Edge Accessory System (EAS).
•Includes light sensitivity meter to dim screen as ambient light decreases
•Internet updateable (cable included)
•Digital gauge display/scan tool (does not reprogram/tune the vehicle or add power)
•Can be used in conjunction with Edge or other performance products to read vital engine data
•Great Value because it monitors much more than just a typical 3-guage cluster
•Displays and clears Diagnostic Trouble Codes
•Displays Alerts and Records such as RPM, MPH and EGT
•Ships with a universal suction cup mount from Arkon, the leader in device-mounting
Capture and record even more information about the vehicle’s performance with the Insight’s scan tool feature.
•Displays and clears diagnostic trouble codes with full text description*
•Displays peak values such as speed and RPM*
•Performance testing: 0-60 and quarter-mile times
•Adjust EFILive™ Tuned PCMS on-the-fly
On 2001-2005 LB7 and LLY Duramax engines you can now change the power levels on-the-fly created by your EFILive™ custom tuning software with your Edge Insight CTS! Simply use your EFILive™ software to change your DSP5 Switch Type from “hard wire” to “serial”. Once you are set up to support “serial” communication, simply use the up and down arrow buttons on your Insight to adjust EFILive™ tunes on-the-fly.
•Displays Fuel Rail Pressure on Duramax Engines
•Displays Diesel Particulate Filter (DPF) Regeneration Status on new diesels with DPF traps
Expandable (items sold separately)
•Compatible with optional Edge Accessory System (EAS) to allow users to connect multiple, additional accessories
•Compatible with optional EGT pyrometer for engine protection
MILEAGE COACH SOFTWARE
The Mileage Coach was designed with fuel economy in mind and features tools to help drivers gauge, monitor, and conserve fuel consumption and MPG.
•Mileage Average, Mileage Instantaneous, and Mileage Coach PIDs*
•Trip Monitor (Monitors fuel cost on trips)
•Fuel Saving Driving Tips including:
MAINTENANCE MANAGER FEATURES
• Customize a comprehensive list of maintenance items to monitor
• Set up and monitor each selected maintenance item based on user-defined parameters
• Set alerts for advance notification of services that are coming due
• Once it has been indicated that a service has been performed, the Maintenance Manager will automatically reset the next service value.
DATA LOGGING SOFTWARE
Fine tune your runs on the track, or prolong the life of your tow vehicle by identifying out of range parameters. The CS/CTS Data Logging feature can show you crucial data to help you identify the “sweet spots” as well as potential problems on your driving experience. Shaving a few tenths of a second off your race time, or running a few degrees cooler make all the difference. The data logging feature allows for a comprehensive, accurate picture of the vehicle’s condition, such as temperatures, pressures, speed, and more!
• Log and store up to 10 unique logs at a time
• Log hours of data
• View and graph logs on your PC using the new MyStyle Software
• View all parameters or pick which ones you want to view
BACK-UP CAMERA (sold separately)
The Insight CTS features a built-in video port that allows users to connect the state-of-the-art Edge back-up camera, or other compatible video source directly to the CTS unit.
PERFORMANCE TESTING, ALERTS & RECORDS
Performance and records 0-60 and quarter-mile times; quarter-mile MPH; peak engine temperature, RPM, speed and transmission temperature values. Sounds audible alerts when user-defined values are reached and automatically records the highest value of key parameters.
EXPANDABLE (items sold separately)
Compatible with optional Edge Accessory System (EAS) to allow users to connect multiple, additional accessories. View more information on EAS accessories click here.
MYSTYLE™ SOFTWARE (included)
MyStyle™ software that allows users to choose from a variety of Edge custom backgrounds or simply upload an image of your choice. Size, crop and save to your CS or CTS unit for the ultimate in customizability.