Engine code
M73 · 5,379 cc · 60-degree V12 · catalog dates 11/1993-07/2001 (all markets) including the later M73N code · E38 750i and 750iL and E31 850Ci
The M73 is a 5,379 cc, 60-degree V12. BMW's parts data lists it in the E38 750 models and in the E31 850Ci. In the U.S. parts data it appears in the 750iL (E38), the 750iLP and the 850Ci.
BMW's parts data uses two codes for these cars. The code is M73 up to 08/1998 on the E38 and M73N from 09/1998. BMW's technical data we read covers the M73 itself, so statements about output and displacement apply to the M73, not the M73N.
In its training on the N73 V12 of the E65 and E66, BMW puts the newer engine's fuel use 3.6 percent below the M73's, and gives it 327 kW, 87 kW more, and 600 Nm against the M73's 490 Nm.
This page is built from BMW's own parts data, service bulletins, training material and NHTSA records. Where those sources are silent, it says so instead of guessing.
Quick read
- Ownership position: Not established yet. We are still researching this engine.
- Reliability: Not established yet. We are still researching this engine. BMW has published service bulletins and NHTSA lists recalls on specific items, listed under Known Failure Points.
- Cost to own: Not established yet. We are still researching this engine.
- Power potential: Not established yet. We are still researching this engine. Factory output is in the Technical Specifications table.
- Main watch item: crankcase ventilation control valves on U.S. M73 cars built from 01/1995 to 05/1999. BMW's bulletin says material fatigue can cause misfires and Check Engine lights.
Where you find it
BMW's U.S. parts data lists the M73 and M73N in these cars. The data we checked runs to December 2019, which is after the engine's production ended.
- 750iL (E38), M73: model years 1995-1998, built 11/1994-08/1998.
- 750iL (E38), M73N: model years 1999-2001, built 09/1998-07/2001.
- 750iLP (E38), M73N: model years 1999-2001, built 04/1999-04/2001.
- 850Ci (E31), M73: model years 1995-1997, built 01/1995-07/1997.
BMW's catalogue also lists the M73 or M73N in other-market E38 models such as the 750i and the 750iLS.
BMW sold the M73 in U.S.-market cars: yes, in the 750iL, the 750iLP and the 850Ci.
M73 At a Glance
| Question | Practical answer |
|---|---|
| Factory output | BMW's technical data lists 240 kW at 5,000 rpm and 490 Nm at 3,900 rpm for the M73. The data does not say which market's rating this is, and we have no output figure for the M73N. |
| Sold in the U.S. | Yes. BMW's U.S. parts data lists the 750iL, the 750iLP and the 850Ci. |
| Reliability profile | Not established yet. We are still researching this engine. |
| Best ownership indicator | Not established yet. We are still researching this engine. |
| Typical annual planning budget | Not established yet. We are still researching this engine. |
| Possible first-year catch-up | Not established yet. We are still researching this engine. |
| Largest common repair exposure | Not established yet. We are still researching this engine. |
| Tuned output | Not established yet. We are still researching this engine. |
| Before buying or modifying | Ask whether the crankcase ventilation control valves were replaced under BMW's bulletin, whether the oil filter support tower is in place on early cars, and whether the E38 cooling fan recall was done on 2001 cars. |
Technical Specifications
| Specification | Detail |
|---|---|
| Configuration | 60-degree V12, 12 cylinders. |
| Engine code as BMW writes it | M73 B54 |
| Displacement | 5,379 cc |
| Bore x stroke | 85 mm x 79 mm |
| Compression ratio | 10.0:1 |
| Power | 240 kW at 5,000 rpm. Rating market not stated. |
| Torque | 490 Nm at 3,900 rpm |
| Maximum engine speed | 6,000 rpm |
| Compression pressure | 10-12 bar, about equal on all cylinders |
| Firing order | 1-7-5-11-3-9-6-12-2-8-4-10 |
| Camshafts | BMW's training material says the M73 uses assembled camshafts, built from separate parts shrink-fitted onto the shaft. |
| Valve count and valve timing control | Not established yet. We are still researching this engine. |
| Induction and fuel system | Not established yet. We are still researching this engine. |
| Engine oil capacity | 8.0 liters with filter change. BMW's fluid data lists the same volume for the 1998-2001 E38 750 models that the parts data codes as M73N. |
| Engine oil specification | BMW of North America's oil chart (SI B11 01 15, February 2017) lists 5W-30 LL01 or 0W-30 LL01FE for all BMW gasoline engines of model year 2011 and older; it does not name the M73 by code. |
| Coolant capacity | Not established yet. We are still researching this engine. |
Factory Deep Dive
Block and cylinder heads
BMW's technical data gives a standard cylinder head height of 140 mm for the M73, with a machining limit of 139.8 mm. BMW's bulletin on a V8 crankcase coating change adds a note that the same changeover applies to the M70 and M73. Its tables list V8 engines only, so we do not know which M73 crankcases are which material.
Valvetrain
Not established yet. We are still researching this engine.
Fuel, ignition and crankcase ventilation
BMW's parts data lists 2 ignition coils on M73 cars and 12 ignition coils on M73N cars, and 12 spark plugs on both. Crankcase ventilation uses a regulating valve for each bank, covered under Known Failure Points.
Cooling
BMW's parts data lists a mechanical coolant pump, 11 51 0 393 339, and a thermostat with connecting bracket, 11 53 1 704 704, on M73 cars. Coolant capacity and operating temperatures: Not established yet. We are still researching this engine.
Variants
BMW's parts data separates the M73 from the M73N, with the change at 09/1998 on the E38. We found no BMW document that says what changed. Not established yet. We are still researching this engine.
Service Parts at a Glance
| Part | BMW part number (current) | Note |
|---|---|---|
| Oil filter element set | 11 42 7 510 717 | Replaces older element numbers. BMW's parts data points to the support-tower bulletin for cars built before 09/1995. |
| Oil filter cover | 11 42 1 736 674 | Current number. |
| Spark plug | 12 12 9 070 999 | Current number. It replaces 12 12 9 068 016. BMW lists 12 spark plugs per car and the plug brand is Bosch. |
| Ignition coil | 12 13 7 599 219 | Current number. It replaces 12 13 1 748 018. |
| Ignition coil, second listed make | 12 13 1 703 228 | Current number, listed for the same cars. |
| Crankcase ventilation regulating valve, cylinders 1-6 | 11 15 7 501 565 | Current number. It replaces 11 15 1 736 411. |
| Crankcase ventilation regulating valve, cylinders 7-12 | 11 15 7 501 564 | Current number. It replaces 11 15 1 736 410. |
| Coolant pump, mechanical | 11 51 0 393 339 | Current number. |
| Thermostat with connecting bracket | 11 53 1 704 704 | Current number. |
| Air filter element, E38 | 13 72 1 702 908 | Current number. BMW lists two per car. Hot-climate cars use 13 72 1 742 202. |
| Air filter element, E31 | 13 72 1 720 861 | Current number. BMW lists two per car. |
| Valve cover gasket, cylinders 1-6 | 11 12 1 725 002 | Current number. |
| Valve cover gasket, cylinders 7-12 | 11 12 1 725 003 | Current number. |
| Timing chain | 11 31 1 710 155 | Current number. The same number is listed for the M70 and S70. |
Known Failure Points and Service Items
These items are limited to what a BMW service bulletin or an NHTSA record says about M73 cars.
01 Crankcase ventilation control valves
BMW's service bulletin (document 00114301) blames material fatigue in the crankcase ventilation control valves: once they wear, the crankcase may no longer vent reliably. BMW lists misfire and fuel-mixture control faults as possible results, with the Check Engine light on. The bulletin names E31 and E38 with the M73, U.S. cars built from 01/1995 to 05/1999.
BMW's fix is to replace both regulating valves. BMW lists them as 11 15 7 501 565 for cylinders 1-6 and 11 15 7 501 564 for cylinders 7-12. BMW's parts data shows these as the current numbers and shows the earlier valves discontinued in 06/1999.
Watch for rough running or misfire, Check Engine light with fuel-mixture control faults, and a car that has not had these valves replaced.
02 Oil filter support tower removed by mistake
BMW's bulletin SI 00 15 97 covers cars built before 09/1995. To take the newer filter element, these cars get a retrofit support tower in the oil filter housing, fitted once and then left in place for every later oil change. BMW suspects many towers are being thrown away with the old element. The bulletin applies to the E31 with M73.
Watch for a housing where the tower is missing or damaged. On housings built after 09/1995 the tower is fixed, and BMW warns that pulling it out can ruin it.
03 Low battery charge and starting problems on E38 M73 LEV cars
BMW's service bulletin (document 00124201) says that on E38 M73 LEV cars built from 08/1998 to 02/2000, frequent short trips with many electrical loads on can leave the battery undercharged at idle, which can lead to starting problems. BMW's remedy is DME programming that raises the maximum idle speed from 700 rpm to 750 rpm.
Watch for hard starting after repeated short trips with many electrical loads switched on.
04 Recalls listed by NHTSA for M73-era cars
NHTSA's records below name models and model years, not engines. BMW's U.S. parts data shows the M73 in the 750iL for model years 1995-1998 and the M73N for model years 1999-2001.
- Recall 95V-238, 750iL model years 1995-1996: NHTSA says fuel can seep where a hose meets the metal fuel line, causing a fuel smell. The consequence line says fuel leakage could potentially result in a vehicle fire. The remedy is replacement of the two fuel hoses, four metal fuel lines and clamps.
- Recall 01V-206, 750iL and 750iLP model year 2001 (M73N in BMW's U.S. parts data): NHTSA says the cooling fan motor can fail and overload the fan control unit, stopping the fan. The consequence line says engine overheating and engine damage could result, and that a fire in the fan control unit is possible. The remedy is a new fan. Recall 02V-138 is a supplement to it.
- Recall 98V-178, 850Ci model year 1995 and 750iL (listed as 750ILA) model year 1995: NHTSA says a failed cooling system part such as the thermostat, water pump or fan belt can sharply raise coolant temperature and pressure, and that a cracked heater core end piece could then release hot coolant. The remedy is a new-design radiator cap. BMW's U.S. parts data lists the M73 in the 1995 850Ci and 750iL.
Reliability Verdict
Not established yet. We are still researching this engine. The items above are documented by BMW or NHTSA. A list of documented items is not a reliability verdict.
Power Potential
Not established yet. We are still researching this engine.
Cost of Ownership
Not established yet. We are still researching this engine.
Common Questions
What BMW has the M73 engine?
In U.S.-market cars, BMW's parts data lists the M73 in the 750iL (E38) for model years 1995-1998 and the 850Ci (E31) for model years 1995-1997. The later M73N code is listed in the 750iL and 750iLP for model years 1999-2001.
How big is the BMW M73 engine?
BMW's technical data gives the M73 a displacement of 5,379 cc, a bore of 85 mm and a stroke of 79 mm in a 60-degree V12.
How much oil does an M73 take?
BMW's technical data lists 8.0 liters for an oil change with a new filter. It does not give the oil grade in the same table.
How much power does the M73 make?
BMW's technical data lists 240 kW at 5,000 rpm and 490 Nm of torque at 3,900 rpm. The data does not say which market's rating that is.
What is the difference between the M73 and the M73N?
BMW's parts data uses M73 for the E38 up to 08/1998 and M73N from 09/1998. We found no BMW document that explains the difference, so it is not established here.
What is the M73 firing order?
BMW's training chart gives the firing order 1-7-5-11-3-9-6-12-2-8-4-10 for the M73, and for the M70 and S70.
Sources
- BMW Engine Technology training, ST501: bmwrepairguide.com technical training PDF
- BMW service bulletins on crankcase ventilation control valves (document 00114301), E38 idle speed and battery charge (document 00124201), the oil filter support tower (SI 00 15 97) and the V8 crankcase coating change (SI 11 01 97), read in BMW's service information
- BMW technical training material comparing the N73 with the M73 (13 01 03), read in BMW's service information
- BMW technical data tables for the M73 (engine general data, cylinder head and oil supply), read in BMW's service information
- BMW electronic parts catalogue data, U.S. and other-market catalogues, data to 12/2019
- NHTSA recall records: 750iL model year 1995, 750iL model year 2001, 850Ci model year 1995
- BMW of North America SI B11 01 15, Engine Oil Quick Reference Chart, February 2017 (NHTSA copy)
- NHTSA recall record 98V-178
