Wednesday, July 6, 2011

Help your 325e, 528e BMW e30, e28 run cooler in the summer. Don't watch your temp. guage riding near the red summer after summer.

Help your 1985-1988 BMW 325e E30 or 528e E28 run cooler in the summer time. Doing these few things will help your engine last longer and the A/C work better. First off make sure that the cooling system is in good working order. By this I mean , no coolant leaks, tight water pump belt, no trash or obstructions in front of radiator, Fan blade without missing blades, fan clutch engaging while engine is running.

Coolant: Make sure that the coolant is mixed properly. BMW part number 82 14 1 467 704 is my choice. Pure antifreeze does not cool (transfer heat) as well as water. So this is one situation where more is not better. Although pure water boils at a lower temperature than antifreeze, water actually dissipates heat better. So don't exceed a 50% mix when filling the system. Its best to research the volume of coolant the system in your vehicle holds and mix a true 50/50 mix in a bucket. Then pour the mixture into the cooling system. We recently reduced cooling system temperature in Supercharged BMW e46 M3 by almost 20 degrees by reducing the coolant to water ratio to 40% antifreeze and 60% water. Remember to switch back for cool winter weather.

Faulty radiator cap: The radiator cap BMW item # 17114379047 is the pressure relief valve of the cooling system. At approximately 17.4 P.S.I. the cap is designed to release the stored pressure. This is to avoid damage to some of the cooling system components. However the systems needs to have the 17.4 P.S.I. of pressure to increase the coolant or water boiling point. Without a cap the coolant will boil out of the system as you drive down the road. So, check the radiator cap carefully. Make sure the seals and "O" rings are in good condition. If in doubt replace it, they are cheap. DO NOT install a generic cap purchased at a local parts store. The fit and the pressure rating are critical. I have repaired many cooling system issues by simply replacing the radiator cap.

Auxiliary fan: Make sure the aux. fan operates on both high and low speed. There are 2 electric fan thermal switches located in one of the vertical radiator side tank. The red one is the (99degree) high speed switch BMW part number 61311364273, and the white is the low speed (91degree) BMW part number 61311364272. Each switch has 2 electrical connectors. To test the fans operation, turn on the ignition (don’t start the engine) and simply use a small screw driver and touch the 2 terminal on the white switch together. The low speed of the electric aux. fan should now be running. Do the same with the red switch terminals and see if the high fan speed comes on. Note when switching on A/C the low fan speed should come on at all times. If the fan does not come on either speed check the fuses. If the fan does not come on in the low speed test the fan resistor BMW part number 17 40 1 373 177 located on the outer fan housing in front of the radiator behind the front grill.

Low temperature auxiliary fan switch: There is a simple trick you can do to make the auxiliary fan come on much sooner to help keep temperatures under control. To do this you will need to remove the red switch (99 degree) and discard it. Then move the wires from the red switch over to the terminal of the white 91 degree switch. Purchase a new 82 degree switch from BMP design and install it in the now vacant hole of the 99 degree switch. To install the remaining wires you will need to change the slip on spade connectors to the larger sizes. What you have now created is an auxiliary fan system that engages the low speed at 82 degree, rather than 91 degrees, and the high speed at 91 degrees, rather than at 99 degrees. To purchase the lower temperature auxiliary fan switch order item number 61 31 6 364 271.

Products > BMW Replacement Parts > BMW Cooling & Heating

Note: to view parts for your model, you will need to enter the year and model in the car selector.
The categories below are for a 1987 BMW 325e E30.
BMW Engine Cooling Parts
Replacement Fan Clutches, Water Pumps, Radiators, Fan Blades, Hose Kits, Clamp Kits, Coolant Tanks and more.
BMW A/C and Heater Parts
Replacement Heater Valves, Heater Valve Repair Kits, Blower Motors and more.
BMW Water Hoses & Clamps
Factory replacement individual water hoses and complete hose kits as well as clamps for those hoses. Includes both cooling and heater hoses.
BMW Blue Coolant / Antifreeze
Part Number: 300800    

1 Gallon of BMW/MINI Blue Coolant Antifreeze (more info)
Products > BMW Replacement Parts > BMW Cooling & Heating


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