Engine code
M70 · 4,988 cc · 60-degree V12 · catalog dates 11/1986-10/1994 (all markets) · E32 750i, 750iL, 750iLS and E31 850Ci
The M70 is a 60-degree V12. BMW's parts data lists it in the E32 750i models and the E31 850Ci. In the U.S. parts data it appears in the 750iL (E32) and the 850Ci (E31).
BMW's parts data lists the M73, a larger 12-cylinder, in the E38 750 models and in later E31 cars. This guide covers the M70 only. Where BMW's documents group it with the M73 and the S70, the guide says so.
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 on specific M70 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: oxygen sensors damaged by exhaust condensation on cars built up to 10/1994. BMW's bulletin on this describes rough idle and a Check Engine light on U.S. cars.
Where you find it
BMW's U.S. parts data lists the M70 in these cars. The data we checked runs to December 2019, after the engine's production ended.
- 750iL (E32): model years 1988-1994, built 09/1987-03/1994.
- 850Ci (E31): model years 1990-1994, built 11/1989-06/1994.
- BMW's parts catalogue also lists the M70 in the 750i and 750iLS (E32) for other markets.
BMW sold the M70 in U.S.-market cars: yes, in the 750iL and the 850Ci.
M70 At a Glance
| Question | Practical answer |
|---|---|
| Factory output | BMW's technical data lists 220 kW at 5,200 rpm and 450 Nm at 4,100 rpm. The data does not say which market's rating this is. |
| Sold in the U.S. | Yes. BMW's U.S. parts data lists the 750iL (E32) and the 850Ci (E31). |
| 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 | BMW's bulletins say the oil filter support tower stays in the filter housing, and describe an oxygen sensor fix for cars built up to 10/1994. Ask whether both are in order. |
Technical Specifications
| Specification | Detail |
|---|---|
| Configuration | 60-degree V12, 12 cylinders. |
| Engine code as BMW writes it | M70 B50 |
| Displacement | 4,988 cc |
| Bore x stroke | 84 mm x 75 mm |
| Compression ratio | 8.8:1 |
| Power | 220 kW at 5,200 rpm. Rating market not stated. |
| Torque | 450 Nm at 4,100 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 |
| Valvetrain 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 management | BMW's bulletins list fault codes for DME M1.2 and DME M1.7 on M70 cars. |
| Engine oil capacity | 7.5 liters with filter change |
| 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 M70 by code. |
| Coolant capacity | Not established yet. We are still researching this engine. |
Factory Deep Dive
Block and cylinder heads
BMW's parts data lists two cylinder heads on the M70. BMW's parts data also lists piston ring repair kits described as Alusil for the M70, for example 11 25 1 718 708.
A BMW bulletin on a V8 crankcase coating change adds a note that the same changeover applies to the M70 and M73, but the bulletin's own tables list V8 engines only.
Valvetrain
Not established yet. We are still researching this engine.
Fuel, ignition and engine management
BMW's parts data lists separate ignition coils for each bank: 12 13 1 742 925 for cylinders 1-6 and 12 13 1 742 926 for cylinders 7-12. It lists 12 spark plugs on the U.S. 750iL.
Cooling
Not established yet. We are still researching this engine.
Variants
We found no BMW document that splits the M70 into variants. 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 an older element number. BMW's parts data points to the support-tower bulletin for M70 cars built before 09/1995. |
| Oil filter cover | 11 42 1 736 674 | Current number. |
| Spark plug | 12 12 9 061 870 | Current number. BMW lists 12 spark plugs per car. The listed plug brand is Bosch. |
| Ignition coil, cylinders 1-6 | 12 13 1 742 925 | Current number. |
| Ignition coil, cylinders 7-12 | 12 13 1 742 926 | Current number. |
| Thermostat | 11 53 1 729 720 | Current number. |
| Air filter element | 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 M73 and S70. |
Known Failure Points and Service Items
These items are limited to what a BMW service bulletin or an NHTSA record says about M70 cars.
01 Oxygen sensors damaged by exhaust condensation
BMW's bulletin SI 11 08 96 blames condensation. On cars driven mostly in stop-and-go traffic or on short trips, water builds up in the exhaust, and a sensor that heats quickly after a cold start can be damaged when that water reaches it. BMW applied this to E31 and E32 M70 cars built from the start of production up to 10/1994.
Watch for an unsteady idle, a shudder through the clutch on the move, and on U.S. cars a lit Check Engine light. BMW lists oxygen sensor fault codes 10 and 28 on the DME M1.2 and 70 and 201 on the DME M1.7.
BMW's remedy, if the sensors keep failing, is to replace them and fit a relay and wiring harness that delays sensor heating after start. BMW lists the oxygen sensor as 11 78 1 733 628, the relay as 11 78 1 745 829 and the harness as 12 51 1 745 758.
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 M70 and the E32 with M70.
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 and that it would not cover a housing damaged that way. BMW lists the retrofit tower as 11 42 1 745 392.
03 Cooling system recall on the 750iL and 850Ci
NHTSA's record for recall 98V-178 lists the 850Ci for model years 1991-1995 and the 750iL, as 750ILA, for 1988-1995. The record does not name an engine. BMW's U.S. parts data shows the M70 in the 750iL for model years 1988-1994 and in the 850Ci for 1990-1994.
NHTSA's summary says a malfunction of a coolant component such as the thermostat, water pump or fan belt can sharply raise coolant temperature and pressure. The consequence line says a crack or seam separation in the heater core end piece could expel hot coolant. The remedy is a new-design radiator cap. Owner notification began March 31, 1999.
Watch for an overheating warning. Whether a given car has the new cap is a question for the car's service record.
Reliability Verdict
Not established yet. We are still researching this engine. The only M70 problems we can point to are the three items above, each backed by a BMW bulletin or an NHTSA record. A short 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 M70 engine?
In U.S.-market cars, BMW's parts data lists the M70 in the 750iL (E32) for model years 1988-1994 and the 850Ci (E31) for model years 1990-1994. BMW's catalogue also lists it in the 750i and 750iLS for other markets.
How big is the BMW M70 engine?
BMW's technical data gives the M70 a displacement of 4,988 cc, a bore of 84 mm and a stroke of 75 mm in a 60-degree V12.
How much oil does an M70 take?
BMW's technical data lists 7.5 liters for an oil change with a new filter. It does not give the oil grade in the same table.
What is the M70 firing order?
BMW's training chart gives the firing order 1-7-5-11-3-9-6-12-2-8-4-10 for the M70, and for the M73 and S70.
How much power does the M70 make?
BMW's technical data lists 220 kW at 5,200 rpm and 450 Nm of torque at 4,100 rpm. The data does not say which market's rating that is.
Did BMW sell the M70 in the United States?
Yes. BMW's U.S. parts data lists the M70 in the 750iL and the 850Ci.
Sources
- BMW Engine Technology training, ST501: bmwrepairguide.com technical training PDF
- BMW service bulletins on oil filter support tower (SI 00 15 97), oxygen sensors on E31 and E32 M70 cars (SI 11 08 96) and the V8 crankcase coating change (SI 11 01 97), read in BMW's service information
- BMW technical data tables for the M70 (engine general data 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 record 98V-178: NHTSA recalls by vehicle, BMW 850Ci
- BMW of North America SI B11 01 15, Engine Oil Quick Reference Chart, February 2017 (NHTSA copy)
- NHTSA recall record 98V-178
