BMW M30 Thermostat Housing Cover with Bleed Screw (11531714861)

Original BMW thermostat housing cover for classic M30 inline-six engines. This aluminum cover closes the thermostat housing and incorporates the coolant outlet connection.

This is the older four-bolt mounting version and is supplied with the installed M8 coolant bleed screw. Suitable for various early BMW M30 cooling-system configurations.

Details

• Part: Thermostat housing cover
• Manufacturer: BMW
• Manufacturer type: Genuine OEM
• Engine family: BMW M30 inline-six
• Material: Aluminum
• Mounting configuration: Four-bolt flange
• Condition: Used
• BMW part number: 11531714861
• Previous BMW part number: 11531250356
• Included: Installed M8 bleed screw
• Supplied exactly as shown in the photographs

BMW Part Numbers

Thermostat Housing Cover

• 11531714861 — 11 53 1 714 861
• 11531250356 — 11 53 1 250 356 — previous version

BMW part number 11531714861 replaces the earlier cover 11531250356.

Coolant Bleed Screw

The installed bleed or vent screw corresponds with the following BMW catalog references:

• 11531275881 — 11 53 1 275 881 — current replacement reference
• 11531250705 — 11 53 1 250 705 — earlier version
• 11531287019 — 11 53 1 287 019 — earlier version
• Thread size: M8

The exact number of the used screw itself is not stamped or readable, but 11531275881 is the applicable BMW replacement number.

Function

This cover closes the thermostat chamber and directs coolant toward the radiator hose. The integrated bleed screw is used to release trapped air while filling and bleeding the cooling system.

This four-bolt cover is associated with older M30 thermostat-housing configurations, including housing references such as:

• 11531250352 — 11 53 1 250 352
• 11531272870 — 11 53 1 272 870

Always compare the four-bolt flange, coolant outlet angle and thermostat-housing design before ordering.

Related BMW Sealing Parts

Depending on the thermostat and housing version, the following sealing components may be required:

• 11531250357 — thermostat housing cover gasket
• 11531250399 — thermostat O-ring
• 11531251041 — 80°C thermostat

These parts are not included unless they are visible in the product photographs.

Vehicle Compatibility

Depending on production date and cooling-system configuration, this four-bolt M30 thermostat cover was used on selected versions of:

• BMW E3: 2500, 2800, 3.0 S, 3.0 Si and 3.3 L/Li
• BMW E9: 2.5 CS, 2800 CS, 3.0 CS, 3.0 CSi and 3.0 CSL
• BMW E12: 525, 528, 528i, 530i and 535i
• BMW E23: 728, 728i, 728iS, 730, 733i, 735i and 745i
• BMW E24: 628 CSi, 630 CS, 633 CSi and selected 635 CSi versions
• BMW E28: selected 525i and 528i versions with the earlier M30 cooling system

Compatibility varies according to model year, market and thermostat-housing version. Later M30 engines may use a different three-bolt thermostat cover.

Condition

Used original BMW component with visible cosmetic wear consistent with its age. The aluminum shows oxidation, discoloration, dirt, scratches and previous installation marks.

The installed bleed screw shows visible surface corrosion. Its operation has not been tested and it should be carefully inspected before attempting removal.

Important Notes

• This is the older four-bolt version
• Do not confuse it with later three-bolt cover 11531268650
• The installed M8 bleed screw is included
• Inspect the bleed screw and threaded opening before installation
• Clean and inspect the sealing surface before fitting
• Installation with a new gasket or O-ring is recommended
• No gasket, O-ring, thermostat or mounting bolts are included
• Compare the flange, outlet position and mounting holes with the original part
• Professional installation and cooling-system bleeding are recommended
• Original BMW component, suitable for an OEM-correct restoration or replacement