Original Bosch BMW E12 / E21 / E28 Auxiliary Air Slide Valve – 0280140100

Original used Bosch auxiliary air slide valve for classic BMW models equipped with an early Bosch fuel-injection system.

This particular component was removed from a BMW E28 528i. Bosch number 0 280 140 100 is officially cross-referenced with BMW part number 13631357891, which is catalogued primarily for the BMW E12 520i and E21 320i.

The auxiliary air slide valve allows additional air to bypass the throttle valve while the engine is cold. This increases the cold idle speed and helps the engine run smoothly during its warm-up period. As the internal heating element warms the valve, the air passage gradually closes and the idle speed returns to its normal level.

Original Bosch auxiliary air valves are discontinued and increasingly difficult to find.

Product details

• Product: Auxiliary air slide valve
• Alternative descriptions: Auxiliary air valve, additional air slide, cold-start air regulator
• German description: Zusatzluftschieber
• Manufacturer: Bosch
• BMW part number: 13631357891
• Formatted BMW number: 13 63 1 357 891
• Short BMW reference number: 1357891
• Bosch part number: 0 280 140 100
• Bosch number without spaces: 0280140100
• Fuel system: Bosch fuel injection
• Function: Provides additional bypass air during cold running
• Installation position: Engine intake and fuel-injection system
• Material: Cast-metal housing
• Donor vehicle: BMW E28 528i
• Condition: Used
• Quantity: One

Vehicle compatibility

Catalogue-confirmed BMW applications

Bosch number 0 280 140 100 and BMW number 13631357891 are officially associated with selected versions of:

BMW 5 Series E12

• BMW 520i with M10 fuel-injection engine
• BMW 520i with M20 fuel-injection engine
• Selected European and market-specific 520i versions using the corresponding Bosch system

BMW 3 Series E21

• BMW 320i with the corresponding early Bosch fuel-injection system

Known donor application

BMW 5 Series E28

• This exact used component was removed from a BMW E28 528i

The donor information confirms that this valve was physically installed on and removed from an E28 528i. However, Bosch number 0 280 140 100 is not the normal catalogue-listed Bosch number for every E28 528i.

Depending on production date, market and fuel-injection specification, the E28 528i is more commonly associated with other calibrated Bosch auxiliary air valves, including:

• Bosch 0 280 140 133 – commonly listed for European E28 525i and 528i applications
• Bosch 0 280 140 124 – found on selected earlier 528i and related M30 fuel-injection applications
• BMW 13631272103 – BMW reference associated with Bosch 0 280 140 124 in selected applications

Bosch auxiliary air valves may share the same general housing shape, electrical connection, mounting arrangement and hose diameters while having different internal opening sizes, temperature characteristics and warm-up calibration.

For an E28 528i, this valve should therefore only be purchased after comparing the Bosch number, hose connections, electrical connector, mounting bracket and cold-air opening with the original valve.

Important compatibility information

Compatibility depends on:

• Vehicle model
• Production date
• Market specification
• Engine type
• Fuel-injection system
• Original Bosch valve number
• Air-hose diameter
• Mounting arrangement
• Electrical connection
• Internal cold-idle calibration

The fact that this component was removed from an E28 528i confirms a previous installation but does not guarantee that Bosch 0 280 140 100 was the original factory-specified valve for that particular vehicle.

Always compare the complete component with the valve currently fitted to the vehicle before ordering.

BMW and Bosch numbers

• 13631357891 – BMW additional air slide valve
• 13 63 1 357 891 – Formatted BMW catalogue number
• 1357891 – Short BMW reference number
• 0 280 140 100 – Bosch manufacturer number
• 0280140100 – Bosch number without spaces

Related BMW M30 auxiliary air valve references that are not identical to the supplied component include:

• 0 280 140 124
• 0 280 140 133
• 13631272103

These related numbers are included for comparison only and should not automatically be treated as identical replacements.

Other Bosch applications

Bosch 0 280 140 100 was also used in selected non-BMW vehicles equipped with Bosch fuel injection, including certain Audi, Opel, Porsche, Renault and Volvo applications.

Although the general valve construction may be similar, calibration and vehicle-specific suitability can differ. Compatibility with non-BMW vehicles is not guaranteed by this listing.

Condition

Original used Bosch component with visible age- and use-related wear, including:

• Dirt and storage residue
• Oxidation across the cast-metal housing
• Surface discolouration
• Marks and wear around the air connections
• Cosmetic wear on the mounting bracket
• Age-related wear consistent with an original fuel-injection component
• Wear and ageing to the accompanying identification tag

The valve has not been cleaned, restored or function-tested.

The condition of the internal air slide and electrical heating element is unknown. Inspection and testing are required before installation. Supplied exactly as shown in the photographs.

Included

• One original Bosch auxiliary air slide valve
• Integrated mounting bracket
• Existing electrical connection
• Existing air-hose connections
• Old handwritten donor identification tag
• Supplied exactly as pictured

No air hoses, hose clamps, wiring plug, mounting bolts, nuts, gaskets or other installation components are included.

Testing and installation recommendation

Before installation:

• Verify Bosch number 0 280 140 100
• Compare the valve with the original component
• Inspect the metal housing and hose connections for damage
• Check that the air passage is open while the valve is cold
• Measure the resistance of the internal heating element
• Bench-test the valve using the correct electrical supply
• Confirm that the internal air passage gradually closes as the valve warms up
• Check that it closes completely within the correct warm-up period
• Clean the internal air passage carefully
• Replace deteriorated air hoses and clamps
• Check the complete intake system for vacuum leaks after installation
• Confirm the cold and warm idle speed after fitting

If the valve remains permanently open, does not allow sufficient air through when cold or does not close when heated, professional overhaul may be required.

Installation and testing should preferably be performed by someone familiar with early Bosch fuel-injection systems.

Storage location: 203