Cooling Systems & Clutch Upgrades

The 2002, 320i (1800 cc's), & 318i
These engines can usually be cooled off by using one of our cool down pulleys, if the radiator is in good shape. A cool down pulley is simply a smaller pulley that turns the water pump and the fan faster. This increases water flow and air movement through the radiator. Resized fan belts are included with all cool down pulleys.

All 320i's
This cooling upgrade consists of a 318i water pump, viscous clutch, cool down pulley and 9 blade fan. This system is great for high heat areas and traffic jams. Also, by using the fan clutch, fan noise is reduced greatly and you get a small power increase.

Clutch
The clutch can be upgraded to a non asbestos woven clutch disc.

The 3500 & 3600 HiFlo ST/Sport

Radiator & Water Pump

• 2002/tii
  • HiCapacity Brass/Copper Radiator (you will need to relocate the battery to the trunk)
  • Curved Fingered Water Pump (no A/C models)
  • Metric Mechanic's HiVolume Water Pump for 2002 - We have developed a curved fingered water pump that increases water flow 10% over stock by helping water flow turn into the front housing.
• 320i
  • MM HiCapacity Plastic/Copper Radiator (this radiator can be adapted into a 2002 without relocating the battery),
  • Cool down pulley
  • M3 water pump
  • Fluid fan clutch
  • 9 blade fan
  • An 86° C fan switch - To top off our cooling package we use an 86° C fan switch versus a 91° C (stock) switch.
• 318i
  • Cool down pulley
  • M3 water pump
  • Fluid fan clutch
  • 9-blade fan
  • An 86° C fan switch - To top off our cooling package we use an 86° C fan switch versus a 91° C (stock) switch.
    

These kits consist of a Metric Mechanic HiCapacity radiator plus installation kit, larger lower radiator hose, Metric Mechanic HiVolume water pump and a 86° C. fan switch.

• Metric Mechanic HiCapacity Radiator vs. Stock Radiator - Our HiCapacity radiator is made of aluminum and plastic for better cooling and service life.
• Metric Mechanic's HiVolume Water Pumps - Increasing engine size and compression, requires upgrading the cooling system. The water pump's output plays an integral part in getting the engine cooled off. The biggest factor affecting water pump volume is the impeller. In a high volume water pump here's our criteria for judging water pump output.
  • Impeller Diameter
  • Impeller Blade Height
  • Number of Blades
  • Inlet Housing Diameter
• Clutch Pressure Plate - The torque output of the 3.8 & 4.0 liter engines will tear a stock 6 cylinder pressure plate apart in less than 600 miles (1000 kilometers). An M5 or M6 pressure plate will last only slightly longer. Metric Mechanic has developed a high torque pressure plate that has 5 strapping bands to hold it together. These bands are put on with high strength cold roll rivets. To compliment this pressure plate we use an asbestos free woven clutch disc liner with a higher coefficient of friction than earlier discs.
  

Radiator

Testing for Radiator Coolant Blockage:
This is a simple test you can use to determine if your 2002 or 320i radiator is plugged up. Using about a 2 foot long piece of mechanics wire, take the radiator cap off and then try to run the piece of wire down the coolant tubes (usually you will be able to test about 6 tubes). If it won't go the bottom, then the radiator is plugged up and needs to be rodded out or re-cored.

Changing the Radiator Core:
To determine the condition of the radiator core, to the far outer corners or the core and check the copper cooling fins to see if they have come loose or crumble (rotted). The fan doesn't blow directly on the core at the corners so usually this area of the core will be the first part to go. If the core is rotted out have it or the radiator replaced. A copper/brass radiator will need rodding out in 3 to 5 years and have a life span of 6 to 9 years.

Fan Switch - Lower Temperature Fan Switch (86°C.)
This is a nice inexpensive upgrade that you can do for your cooling system. The factory fan switch doesn't click on until 92°C. and is usually located in the bottom of the radiator on earlier BMW's (this is the coolest water in your radiator). So, normally you're almost overheating before your fan clicks on. By going to an 86°C. fan switch you have a fair amount of safety margin before overheating. This safety margin can be increased by locating the fan switch in the thermostat housing (as used on later 6 cyl. BMW's).

Late Model Thermostat Housing
This housing allows you to mount a coolant fan switch or accessory temperature gauge sending unit.

Troubleshooting a Bad Fan Clutch
With the engine cold and not running, grab the fan and try to spin it over. There should be enough fluid drag that the fan shouldn't be able to spin more than 1/2 to 3/4 of a turn. It's not that uncommon a practice to see BMW owners lock up fan clutches or eliminate them altogether, this not only makes the car very noisy (fan noise) but you lose some free horsepower.

Replacing the Fan Clutch
On earlier 6 cylinder BMW's that used viscous clutches, the clutch is held on with an 8 mm bolt. On later BMW 3,5,6& 7 series (E-30, Body) the fan clutch screws off by turning a 30 mm left hand threaded nut (turn it clockwise to loosen). This nut takes a thin wrench to get at and can be made by buying a 30 mm or 1 1/8" wrench and grinding it to fit.