The main difference between model designations is that the popular 325i was enlarged from a 2.5-liter to a 2.8-liter engine to become the 328i. The 2.5-liter engine was retained, however, as the 323i. This engine is identical to the previous 325i but detuned to 168 hp. This was presumably done to give the 328i a horsepower advantage.
The following sections offer some information on the various models of E36 available in the North American market.
4-Cylinder Cars
Four-cylinder E36 BMWs included the 318i and 318ti sold in the United States and Canada 1992–1998, and the 320i sold in Canada 1993–1995.
It is worth noting that the 318ti hatchback and the Z3 roadster and coupe are substantially different from all other E36-class vehicles in that the chassis and rear suspension are not the same. The rear suspension on these cars is a carry-over from the older E30 BMW line. Therefore, procedures in this book relating to the rear suspension and chassis are not directly applicable to these cars. The front suspension and steering gear are common to all E36 cars.
Maintenance and Repair Schedule: The 80,000-Mile Rule
As the E36 series has aged, mechanics have had the opportunity to notice trends in required repairs. What they have found is that 80,000 to 100,000 miles or about 8 to 10 years of service is a watershed for these cars. A number of items consistently need attention at that interval. Almost all E36 cars are well past that mileage at this date and are now coming up on their second rounds at 160,000 to 180,000 miles, or 16 to 20 years of service.
If you have not yet purchased your E36, keep these items in mind as you compare candidate cars. Ask to see service records for claimed maintenance and repairs. If you already own your E36, consider the accumulated mileage on your car and look over this list for items that you have not yet checked or repaired.
• The cooling system is mainly made of plastic, and the entire system needs to be replaced about every 80,000 miles. Wear symptoms include cracking in the radiator neck, tanks, hoses, thermostat housing, and water pump.
• Engine pulleys, the idler and tensioner especially, must be replaced about every 100,000 miles. While you have that all apart, the oil filter stand O-ring gasket generally needs to be replaced at the same time.
• The stock flywheel is a dual-mass assembly designed for smooth takeoff and shifting. This wears out at roughly 100,000 miles and must be replaced. For performance builds, a solid single-mass flywheel is a good upgrade. Single-mass flywheels are also less expensive than the OEM dual-mass replacement.
• The driveshaft flex disc (also known as the Guibo) and driveshaft center support bearing must be replaced at about 100,000 miles.
• Manual transmission shift bushings must be replaced at about 100,000 miles. This is a good opportunity to upgrade to a short shifter.
• Engine and transmission mounts may be oil-soaked and decayed. Check and replace these as necessary at 80,000 miles.
• The valvecovers for 1996 and later cars are plastic that hardens over time and has a tendency to crack. This creates a vacuum leak that throws off engine tuning and may trigger a check engine light. Valvecover gaskets also harden and require replacement at about 80,000 miles.
• If the cooling system has failed at 80,000 to 100,000 miles and the engine has overheated, check the cylinder head for cracks and leakage. The stock E36 water temperature gauge does not read hot until the engine is very hot and damage to the head is likely to have occurred. Plus, E36 cylinder heads are known for cracking with age, even if overheating has not occurred.
The water pump is just one of many components on the E36 series that must be replaced every 80,000 to 100,000 miles. If you’re shopping for an E36, pay careful attention to the mileage and ask for maintenance records to show that required tasks have been completed.
Looking at the E36 engine bay, you see a lot of plastic. Many of these components become brittle and crack over time and mileage. Specifically, the radiator and cooling system components are a frequent failure point at about 80,000 to 100,000 miles.
The 318i sedan, however, is a true E36 chassis and step-by-step projects relating to the rear suspension and chassis are applicable to these cars, if you can find one in the United States.
The M42/M44 series 4-cylinder engines are a carryover from the E30 line but are equipped with DOHC and four valves per cylinder, with an iron block and aluminum heads. These engines feature strong forged cranks and header-style exhaust manifolds in the long block and a Bosch Motronic ignition that eliminated the distributor in favor of individual coils.
Weak points in these engines included coolant gaskets in the timing case, which allowed coolant into the oil sump. The M44 engine series adopted in 1996 eliminated this problem, and the updated parts can be installed on the M42 engines.
318i (1992–1998)
The 318i sedan, 318is coupe, and 318ti hatchback used the M42B18 engine from 1992 to 1995. This engine displaces 1,796 cc and generates a maximum of 138 hp at 6,000 rpm, and 129 ft-lbs of torque at 4,500 rpm.
For the 1996–1998 model years, the 318 series switched to the slightly larger M44B19 at 1,895 cc, developing the same 138 hp at 6,000 rpm and improving slightly to 133 ft-lbs of torque at 4,300 rpm.
320i (1993–1995)
Canadian buyers were offered the E36 with the traditional M50B20 engine displacing 1,991 cc in the 320i. This engine was good for 148 hp at 6,000 rpm and 140 ft-lbs of torque at 4,300 rpm. This model was not offered in the United States, but some examples may be found.
6-Cylinder Cars
By far the greatest number of E36 chassis sold in North America included some version of BMW’s inline 6-cylinder engine. This started with the 2,494 cc M50B25 in the 325i line in 1992. The M50 engine family used a cast-iron block and aluminum alloy head, with four valves per cylinder and DOHC. After the 1992 model year, E36 models in America received the M50B25TU engine, which featured variable cam timing on the intake cam only. BMW called this VANOS, an abbreviation of its German name.
The M50 line was upgraded to the M52 line for the 1996 model year along with the advent of OBD-II across the North American BMW line. European versions of the M52 used an engine block made from Nikasil aluminum; North American engines used an iron block due to high sulfur concentrations in American fuel. In 1999, the M52 received a technical update to implement VANOS on the exhaust cam as well as the intake, but the M52TUB28 engine was never sold on the E36 chassis. However, this engine can be retrofitted for a small boost in mid-range torque.
The 325i series was available with two or four doors, with the two-door bearing the designation 325is. This series carried the M50 engine of 2.5-liter displacement.
The most powerful of the 6-cylinder engines were the S50 and S52 series, used in the U.S.–market M3 editions of the E36. These engines used the same heads and engine block as their more prosaic counterparts but were enlarged in both bore and stroke and included high-performance cams and valve-trains to increase performance by about 50 hp.
325i (1992–1995)
The 325i was introduced in 1992 as a four-door sedan or two-door coupe using the M50B25 engine, displacing 2,494 cc and generating 189 hp at 5,900 rpm. Maximum torque was 181 ft-lbs at 4,700 rpm. The