Engine code
The M42 is BMW's 1.8 liter (1,796 cc) four-cylinder gasoline engine with two overhead camshafts and 16 valves. BMW's parts data lists it in US-market cars: the E30 318i and 318is (built 12/1989-12/1992) and the E36 318i, 318is and 318ti (built 12/1991-01/1996).
From 01/1996 BMW's parts data shows the 1.9 liter M44 on the same E36 models. This guide covers the M42 only. The M44 has its own guide, and the earlier 8-valve M40 and the M43 are separate engines.
Quick read
- Ownership position: Not established yet. We are still researching this engine.
- Reliability: Not established yet. We found two BMW service bulletins for these cars (oxygen sensor lead routing and heater output, below) and have not matched any recall to this engine. That is not a verdict.
- Cost to own: Not established yet. We are still researching this engine.
- Power potential: Not established yet. BMW's data sheet gives a factory output of 100 kW (about 134 hp). It gives no tuning figures.
- Main watch item: Not established yet. The only BMW bulletins we found for US M42 cars are listed under Known Failure Points.
M42 At a Glance
| Question | Practical answer |
|---|---|
| Sold in US-market BMWs | Yes. BMW's parts data lists the M42 in US-market E30 and E36 3 Series cars. |
| Displacement | 1,796 cc, 84 mm bore x 81 mm stroke |
| Factory output | 100 kW at 6,000 rpm and 172 Nm at 4,600 rpm |
| Cam drive | Timing chain with a hydraulic tensioner |
| Engine oil capacity | 5.0 liters (about 5.3 US quarts) with a filter change |
| Engine oil specification | BMW of North America's oil chart (SI B11 01 15, February 2017) lists 5W-30 BMW Longlife-01 or 0W-30 BMW Longlife-01 FE for all BMW gasoline engines of model year 2011 and older. |
| Coolant capacity (E36) | 6.5 liters, or 6.7 liters with integrated air conditioning |
| Reliability profile | Not established yet. |
| Typical annual planning budget | Not established yet. |
| Common tuned street range | Not established yet. |
| Before buying | Ask a BMW dealer to check the VIN for open recalls and service campaigns. |
Where you find it
Rows are BMW's US-market parts data, with build months. The parts data used here ends in December 2019.
| Chassis and models (US market) | Built (BMW) |
|---|---|
| E30 318is | 12/1989-04/1991 |
| E30 318i four-door | 05/1990-04/1991 |
| E30 318i convertible | 08/1990-12/1992 |
| E36 318i sedan | 12/1991-11/1995 |
| E36 coupe (318is) | 12/1991-12/1995 |
| E36 318i convertible | 01/1994-01/1996 |
| E36 318ti Compact | 01/1995-11/1995 |
Outside the US, BMW's type list also shows the M42 in the European-market E36 318is coupe and sedan, the E36 318ti and the E30 318is, and in the South African E36 318i sedan.
Technical Specifications
| Specification | Detail |
|---|---|
| Configuration | Inline four-cylinder, 16 valves, double overhead camshafts |
| Displacement | 1,796 cc · 84 mm bore x 81 mm stroke |
| Compression ratio | 10.0:1 |
| Power | 100 kW (about 134 hp) at 6,000 rpm |
| Torque | 172 Nm (about 127 lb-ft) at 4,600 rpm |
| Maximum engine speed | 6,500 rpm |
| Valve head diameter | 33.0 mm intake, 30.5 mm exhaust |
| Cam drive | Timing chain, hydraulic tensioner |
| Engine management | Digital Motor Electronics (DME) M1.7 |
| Oil capacity | 5.0 liters with filter change |
| Oil pressure | 4.3 bar regulated pressure, with a 0.5 bar minimum at idle when hot |
| Coolant | 6.5 liters (6.7 liters with integrated air conditioning), E36 |
| Thermostat | Opens at 92 degrees C |
| Spark plugs | NGK BKR 6 EK or Bosch F7 LDCR |
| Engine oil specification | 5W-30 BMW Longlife-01 or 0W-30 BMW Longlife-01 FE (BMW of North America oil chart) |
| Firing order | Not established yet. |
Factory Deep Dive
Block, head and rotating assembly
Wikipedia lists the M42 as having a cast-iron block, an aluminum head and a forged steel crankshaft. BMW's data sheet gives a cylinder head height of 140.0 mm when new.
Valvetrain and timing chain
The M42 uses a timing chain, and BMW's repair data describes a hydraulic chain tensioner for it. BMW's repair data says the hydraulic chain tensioner from the M44 may also be fitted to an M42. BMW's repair data also refers to bucket tappets in this valvetrain.
Fuel, ignition and air
BMW's parts data lists one ignition coil per engine on the E36 M42 from 01/1994. The injection valves are listed four per engine. Spark plug numbers are in the parts table below.
Cooling
The M42 uses a mechanical coolant pump. BMW's data sheet gives a fan clutch that switches on at 92 degrees C (plus or minus 4) and off at 60 degrees C. Coolant capacity and thermostat opening temperature are in the specifications table.
Variants and markets
The M42 B18 is the only M42 version in the BMW data opened here. BMW's data sheet lists 100 kW for it. Wikipedia gives 103 kW (140 PS) for the E36 cars, which we have not confirmed from a BMW document, so the E36 output is not established.
Service Parts at a Glance
Numbers below were looked up in BMW's parts data (to December 2019) and show the current number.
| Part | BMW part number | Note |
|---|---|---|
| Oil filter element set | 11 42 1 716 192 | Current; supersedes 11 42 1 432 097. Plastic-cover housing, US M42 and M44. |
| Oil filter element set, aluminum-cover housing | 11 42 1 727 300 | Current; US M42 only |
| Oil filter cover | 11 42 1 715 960 | Current; supersedes 11 42 1 743 303 |
| Air filter element | 13 72 1 247 404 | Current; supersedes 13 72 1 247 405. E36 M42 from 03/1994. |
| Spark plug (Bosch F7 LDCR) | 12 12 9 063 428 | Current; four per engine |
| Spark plug (NGK BKR 6 EK) | 12 12 9 064 619 | Current; four per engine; also fits the E30 M42 |
| Ignition coil | 12 13 1 247 281 | Current; E36 M42 from 01/1994 |
| Coolant pump, mechanical | 11 51 0 393 338 | Current; supersedes exchange water pump 11 51 1 734 602 |
| Thermostat, 92 degrees C (E36) | 11 53 7 511 083 | Current; E36 M42 |
| Thermostat, 88 degrees C (E30) | 11 53 7 511 580 | Current; E30 M42 |
| Cylinder head gasket, 2.04 mm (+0.3) | 11 12 1 721 550 and 11 12 1 721 551 | Both listed as current; 721550 points to 721551 |
Known Failure Points and Service Items
Recall status: NHTSA's recall search lists recalls by model and model year, not by engine. It lists a 1997 cruise control and throttle cable recall (97V131) for the 1995 318i. We have not matched it to an engine, so it is not described here. Whether a car is covered is a VIN check with BMW or NHTSA.
01 Oxygen sensor connection lead (E36 US, manual, 1995 model year)
BMW Service Information 00 11 21 01 covers E36 cars with the M42 and a manual transmission built for the US from 09/1994 to 01/1996. Per BMW, on some of these cars the factory clipped the sensor lead to the exhaust heat shield or to a transmission bracket. As the exhaust moves against the body, that clipping can pull on the lead and eventually break it at the sensor plug. Dealers were told to free the lead from those clips and fit a new sensor where needed.
Watch for the check engine lamp with fault code 70, oxygen sensor open circuit.
02 Low heater output at idle (E36, built through March 1996)
BMW Service Information 64 03 97 lists the E36 gasoline engines M42, M43, M44, M50 and M52, from the start of series production through March 1996. The cause BMW names is not enough coolant flow through the heater. The fix is to inspect the thermostat and the heater water valve and renew either one if needed; Compacts with the basic heater control have no water valve.
Watch for weak heat at idle with normal heat while driving.
Reliability Verdict
Not established yet. We are still researching this engine. Two service bulletins are not a measure of how often anything fails, and we have no BMW document that gives failure rates or mileage.
Power Potential
Not established yet. BMW's only figure is the factory output in the specifications table.
Cost of Ownership
Not established yet. We have no sourced figure for annual cost, repair reserve or catch-up work on this engine.
Common Questions
What BMW has the M42 engine?
BMW's parts data lists the M42 in the US-market E30 318i and 318is (built 12/1989-12/1992) and the E36 318i, 318is and 318ti (built 12/1991-01/1996).
How much oil does an M42 take?
BMW's data sheet gives 5.0 liters (about 5.3 US quarts) for an oil change with a filter. For the grade, BMW of North America's oil chart lists 5W-30 Longlife-01 or 0W-30 Longlife-01 FE for gasoline engines of model year 2011 and older.
Does the M42 have a timing belt or a timing chain?
The M42 has a timing chain with a hydraulic tensioner, per BMW's repair data.
Was the M42 sold in the US?
Yes. BMW's parts data lists it in US-market E30 and E36 3 Series cars.
How much power does the M42 make?
BMW's data sheet for the M42 B18 lists 100 kW (about 134 hp) at 6,000 rpm and 172 Nm at 4,600 rpm.
What is the difference between the M42 and the M44?
BMW's data sheets list the M42 at 1,796 cc (84 mm x 81 mm) and the M44 at 1,895 cc (85 mm x 83.5 mm), and BMW's parts data shows the M44 on the same US E36 models from 01/1996.
Sources
- Wikipedia, BMW M42 (basics only)
- NHTSA recall search, BMW 318i, 1995
- BMW parts catalog data, US market, data to December 2019
- BMW of North America SI B11 01 15, Engine Oil Quick Reference Chart and Drain Plug Torque (February 2017)
- BMW technical data sheets and service information bulletins 00 11 21 01 and 64 03 97
