Click Here for Latest BMW Articles

E36 BMW Check Coolant Level OBC Message
E30 BMW 3 Series Pre Purchase Checklist
E36/E46 Rear Trailing Arm Bushing (RTAB) Replacement 1
E36/E46 BMW Rear Shock Mount (RSM) Replacement
BMW Control Arm Bushing Replacement Tips
E36 Exhaust Replacement and M3 Exhaust Swap Upgrade
E36 Warped Rotors, Ceramic Pads, and the Fix
E36 Warped Rotors and Brake Pad Deposits
E30 318i and 318is Suspension and Tie Rod Replacement
Replacing your BMW's fuel filter
BMW Cooling System Flush/Refill Part 2
BMW Cooling System Flush/Antifreeze/Refill I
E36 BMW Power Window Problems and Repair
BMW Headliner Repair and Replacement
M50 Intake Manifold Swap for 328i/328is and M3
E28 BMW 5 Series History and Information
More Power for BMW 2002 and 2002tii Part 2
More Power for BMW 2002 and 2002tii Part 1
Replacing E36 and E46 BMW Tie Rods
Hints and Tips for Washing and Waxing your BMW
Performance Modifications for E36 M52 328i and 328is
1991 E30 318is Performance Mods
E36 BMW 3 Series Oxygen Sensor Replacement Instructions Part 2
E36 BMW 3 Series Oxygen Sensor Replacement Instructions Part 1
E30 325i and 325is vs E30 M3: The Better Street Car
Suspension and Handling Upgrades for E34 BMW 5 Series Sedans
BMW Differential Repair, Replacement, and Upgrades Part 2
BMW Differential Repair, Replacement, and Upgrades Part 1
E46 3 Series Wear Items Checklist: What To Expect
E30 BMW 3 Series History and Performance
E34/E36/E39 M50/S50/M52/S52 BMW Engine Coil Replacement
E36 3 Series Wear Items Checklist: What To Expect
From E12 to E39: BMW M5 and M535i History and Development
My BMW Dream Garage
More BMW Radiator and Cooling System Information
BMW Radiator and Cooling System Information
How To Get More Horsepower From 2.7 ETA-engine BMWs
Performance Mods for M20 2.5 i engines
Replacing Sparkplugs and Valve Cover Gaskets
E24 BMW 6 Series History and Development: The Shark
Brief History of the M3: From E30 to E46
E36 M3 vs E36 325is and 328is: Performance Comparison
Replacing E30, E36, and E46 Ball Joints
E36 BMW Slip Ring Replacement and Why It Fails
Buying BMW Parts Online
BMW World
BMW Car Club of America
BMW Car Magazine
Rennlist BMW Site
Ben Liaw's BMW Links
BMW Nation
BMW E21 Info
Bimmers.Com BMW Info
Global web directory project

Powered by Blogger

Blog Directory

E34/E36/E39 M50/S50/M52/S52 BMW Engine Coil Replacement

In a previous article, I detailed the procedure for replacing the sparkplugs and valove cover gasket on all BMW cars powered by derivates of the M50 engine. An item not mentioned, and probably should have been, are the coils, especially on older or higher mileage cars. With age and heat, the insulation breaks down. As variants of the M50 engine are found in the E36 3 series as well as E34 and E39 5 series, this article applies to any cars with these engines, ranging from the 1991 525i to the 1999 M3.

Just like the spark plugs can be a source of intermittent hesitation or bogging, so too can the coils themselves. Do a simple search on in the appropriate forum and you will see countless tales of coil woe. In the early days of the E36, coil failure manifested itself so often that there was a push for recall by BMW. Coil problems can manifest themselves as bucking, surging, or general hesitation, often under load or part to full throttle in the 500-3000 rpm range. The dealership will tell you that the coils need to be replaced as a set, but this is not true. Many independent BMW parts retailers (like bimmerparts and bavauto) sell individual coils. Here's one way to test your cars coils if the above symptoms are indeed occurring:

Replace all the spark plugs, first off. This is eliminating a variable and doing preventative maintenance at the same time. Next, purchase 1 new coil (You might want to check the shop you are buying parts from's policy on returning electrical or ignition components, it does you no good to buy 3 coils if it turns out you only have 1 bad one and you are stuck with 2 extra ones.) and replace the coil on the first cylinder closest to the front of the car. See if this cures it. If not, put it on cylinder #2. Rotate the new coil through all six cylinders. If no single replacement cures the issue, try a second coil and rotate through. This is the least expensive way. You could alway just replace all six at once for peace of mind. Now, old coils are prone to cracking, and a cracked coil can lead to serious electrical problems and can even damage the DME unit (ECU/chip) on your car. A new DME/chip from the dealer is $1000! You can also easily check the health of your coils by checking the resistance between two terminals on the coil. This is outlined in the Chilton's manula and the factory Bentley repair manual. There were two different sources for the coils used by BMW, Bosch and Zundspule. The Zundspule coils were made by a vendor called "May und Christ". These have been the more problematic ones, with peristent tales of misfiring and rough idle.

BMW parts, information, news, modification, repair, and info on BMW 2002,2002tii,2002ti,3.0cs,3.0csi,3.0csl,530i,528e,528i,525i,525it,528xi, 535i,535is,540i,545i,318i,318is,318ti,320i,320is,323i,323is,325i,325e,325is,325ix,325xi,325ic ,325ci ,328i,328is,328ic,328ci,330i,330ci,M3,M3 EVO,M3 Evolution,M3 sport evolution,M5, M6, Z3, Z8, M coupe, M Roadster, 633csi,635csi,euro 635csi,M635csi,735i,740i,750il,740il,745i,E9,E12,E21,E23,E24,E26,E28,E30,E31,E34,E36,E38,E39 ,E46,E52,E53,E60,E65,E66
BMW cars, parts, bmw information, fixing bmw's, bmw resoruces, links, BMW performance, BMW racing