Genuine BMW M30 Thermostat Housing 11531272870 – 1981/82

Genuine used BMW thermostat housing for M30 inline-six engines, manufactured around 1981/1982.

This original aluminium thermostat housing has three threaded sensor ports. One temperature-related sensor is installed and included; the other two sensor ports are empty. The original rounded thermostat cover and the bleed screw are also included.

The housing carries casting number 1 250 351.9. This is a casting number rather than the complete BMW ordering number. Based on its production period and configuration, the most relevant BMW numbers are 11531272870 and 11531278187.

Because the required sensors and connections vary by model, production date and engine-management system, always compare the housing and electrical connections before ordering.

Details

• Part: Thermostat housing assembly
• Manufacturer: BMW
• Manufacturer type: Genuine OEM/OE
• Engine family: BMW M30 inline-six
• Material: Cast aluminium
• Condition: Used – untested
• Approximate casting period: 1981/1982
• Casting number: 1 250 351.9
• Probable period BMW number: 11531272870
• Alternative period number: 11531278187
• Sensor configuration: Three threaded sensor ports
• Installed sensors: One
• Empty sensor ports: Two
• Included: Thermostat housing, rounded cover, one sensor and bleed screw
• Supplied exactly as shown in the photographs

BMW Thermostat Housing Part Numbers

The number 1 250 351.9 cast into the aluminium is a casting or manufacturing number, not the complete BMW ordering number.

Relevant BMW part numbers for this production period include:

• 11531272870 — 11 53 1 272 870
• 11531278187 — 11 53 1 278 187

Known BMW supersession sequence:

• 11531250352 — 11 53 1 250 352
• 11531263058 — 11 53 1 263 058
• 11531271475 — 11 53 1 271 475
• 11531272703 — 11 53 1 272 703
• 11531272870 — 11 53 1 272 870
• 11531278187 — 11 53 1 278 187
• 11531710959 — 11 53 1 710 959 — final later replacement version

The exact original ordering number cannot be confirmed from casting number 1 250 351.9 alone, as BMW used this basic casting across several revisions.

Later replacement housings may use different thermostats, covers and sealing arrangements.

Installed Sensor

One brown two-terminal temperature-related sensor is installed and included.

Based on its appearance and period, it may be one of the following BMW temperature-time switches:

• 13621274630 — 13 62 1 274 630 — early temperature-time switch
• 13621362599 — 13 62 1 362 599 — later replacement

The number stamped on the installed sensor is not readable. Its exact BMW number, specification and function are therefore not guaranteed.

The sensor has not been electrically tested and is supplied as shown.

Sensor Connections

The housing has three available sensor positions. Depending on the vehicle and engine-management system, these positions could be used for components such as:

• Coolant-temperature sensor for the injection system
• Temperature sender for the instrument-cluster gauge
• Temperature-time switch for the cold-start injection system
• Temperature warning contact
• Suitable sealing plug for an unused port

Associated BMW sensor numbers can include:

• 13621274630 — temperature-time switch
• 13621362599 — later temperature-time switch
• 13621357414 — coolant-temperature sensor, 20°C/2500 ohm
• 13621709966 — M12 × 1.5 temperature sensor
• 62111268355 — temperature sender for the instrument cluster
• 62161360870 — temperature sending unit/warning contact

The correct combination depends on the vehicle’s production date, wiring harness, injection system and market specification. Two sensor positions are empty, and additional sensors or sealing plugs are not included.

Thermostat Cover and Bleed Screw

The rounded thermostat cover and its bleed screw are included.

Associated BMW reference numbers include:

• 11531714861 — 11 53 1 714 861 — thermostat cover
• 11531250356 — 11 53 1 250 356 — earlier cover number
• 11531275881 — 11 53 1 275 881 — M8 bleed/vent screw
• 11531250357 — 11 53 1 250 357 — thermostat-cover paper gasket
• 11531250399 — 11 53 1 250 399 — thermostat sealing ring
• 11531254065 — 11 53 1 254 065 — associated 80°C thermostat

These reference numbers are provided for identification and servicing purposes. Parts are only included when physically present and shown in the photographs.

Vehicle Compatibility

Depending on production date, engine version and sensor configuration, this three-port thermostat housing may be suitable for select BMW models with an M30 engine, including:

• BMW E12: 525, 528, 528i and 535i
• BMW E23: 728, 728i, 730, 732i, 733i, 735i and 745i
• BMW E24: 628 CSi, 630 CS, 633 CSi and 635 CSi
• BMW E28: 525i, 528i, 533i, 535i and M535i

It may also be usable on certain earlier M30 applications when the correct sensors or sealing plugs are installed. This should always be verified before ordering.

Compatibility depends on:

• Vehicle production date
• Engine-management or injection system
• Number and thread size of the required sensors
• Electrical connector types
• Coolant-hose arrangement
• Thermostat and cover design

Always compare the original housing and verify compatibility using the vehicle’s VIN.

Condition

Used original BMW component in unrestored condition.

The housing shows normal age-related wear, oxidation, dirt, old coolant deposits and surface discolouration. Oxidation is visible around several coolant connections. The bleed screw also shows surface corrosion.

The following components have not been tested:

• Aluminium thermostat housing
• Installed sensor
• Internal thermostat
• Thermostat cover and bleed screw

The housing has not been pressure-tested. The presence, type and operating condition of the internal thermostat have not been verified.

Cleaning and careful inspection are required before installation. Replacement of the thermostat, paper gasket, sealing rings and any missing sensors or sealing plugs is recommended.

Important Notes

• Casting number: 1 250 351.9
• Approximate casting period: 1981/1982
• Probable BMW number: 11531272870
• Alternative BMW number: 11531278187
• Configuration: Three sensor ports
• One sensor is installed and included
• Two sensor ports are empty
• Bleed screw is installed and included
• Exact sensor number and operation are not guaranteed
• Missing sensors or sealing plugs are not included
• Internal thermostat has not been inspected or tested
• Housing has not been pressure-tested
• Install using new gaskets and sealing rings
• Supplied exactly as photographed
• Ideal for restoration or refurbishment of a classic BMW M30 cooling system