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Rein CPE0050 Engine Coolant Reservoir CapOE Quality 60-Day Returns
Part #: CPE0050

Rein CPE0050 Engine Coolant Reservoir Cap

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21 vehicles fit this part
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OE Direct Replacement — Bolt-on fit, no modifications needed
Fitment: Porsche and BMW, 928, 635CSi, 535i, and 735i
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Not what you need? See all Engine Coolant Reservoir Cap options

OE Quality Expansion Tank Cap

Rein CPE0050 is an OE-quality engine coolant reservoir cap built as a direct replacement for the factory cap. It helps maintain the cooling system pressure required for proper operation on BMW 535i, BMW 635CSi, BMW 735i, and Porsche 928 applications.

Key Features

  • Manufactured to strict engineering standards for materials and tolerances.
  • Direct fit for application-specific cooling system use.
  • Meets or exceeds OE pressure specifications.
  • Produced by an original equipment supplier.
  • Black and silver finish.

Detailed Product Overview

Rein CPE0050 expansion tank cap is designed to replace the original coolant reservoir cap without changing the factory cooling system setup. Built to match or exceed OE material requirements, this cap helps preserve the pressure balance needed in the expansion tank and cooling circuit. It is a practical choice for owners servicing classic BMW and Porsche models, including Fits 1985-1988 BMW 535i, N/A; Fits 1985-1989 BMW 635CSi, N/A; Fits 1985-1986 BMW 735i, N/A; Fits 1985-1991 Porsche 928, N/A; and Fits 1993-1995 Porsche 928, N/A.

This part cross-references BMW and Porsche OE numbers for the same application, including 17111100848 and 92810625700.

Common Cooling System Issues Addressed

  • Loss of coolant system pressure from a worn or weakened cap.
  • Coolant overflow caused by a cap that no longer seals correctly.
  • Pressure irregularities that affect expansion tank operation.
  • Service replacement for cracked, aged, or corroded reservoir caps.

Installation Notes and Tips

Install CPE0050 on the correct application-specific expansion tank and verify the cap seats fully before driving. Inspect the reservoir neck, sealing surface, and surrounding cooling system components for wear or damage during service. After installation, confirm the cooling system reaches and holds normal operating pressure.

Quality Assurance

Rein manufactures this cap to OE-quality standards and sources it from an original equipment supplier. It is backed by a 24-month or 24,000-mile warranty.

BrandRein
Part NumberCPE0050
Application TypeApplicationSpecific
ColorBlackSilver
Container TypeBG
Country of OriginDE
Item Height0.9200
Item Length3.3000
Item Level GTIN888544105029
Item Qty1
Item UOMEA
Item Weight0.1600
Item Weight Unit UOMLB
Item Width2.3000
Link to Manufacturer Pagewww.reinautomotive.com
Product Desc Extended 240Rein OE Quality expansion tank caps are designed to be direct replacements for OE caps. Rein caps are designed to match or exceed the OE materials used and are produced to the highest standards to ensure long service life.
Product Desc Invoice 40Rein Expansion Tank Cap
Product Desc Long 80Rein OE Quality Expansion Tank Cap
Product Desc Short 20Expansion Tank Cap
Warranty Distance24000
Warranty Time24

This part fits 21 vehicles. Search below:

YearMakeModelLitersCylindersPositionNotes
1995Porsche9285.4LV8N/A
1994Porsche9285.4LV8N/A
1993Porsche9285.4LV8N/A
1991Porsche9285.0LV8N/A
1990Porsche9285.0LV8N/A
1989BMW635CSi3.5LL6N/A
1989Porsche9285.0LV8N/A
1988BMW535i3.5LL6N/A
1988BMW635CSi3.5LL6N/A
1988Porsche9285.0LV8N/A
1987BMW535i3.5LL6N/A
1987BMW635CSi3.5LL6N/A
1987Porsche9285.0LV8N/A
1986BMW535i3.5LL6N/A
1986BMW635CSi3.5LL6N/A
1986BMW735i3.5LL6N/A
1986Porsche9285.0LV8N/A
1985BMW535i3.5LL6N/A
1985BMW635CSi3.5LL6N/A
1985BMW735i3.5LL6N/A
1985Porsche9285.0LV8N/A

* Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.

This part directly replaces or is cross-referenced with the following part numbers:

Cross-reference numbers are provided for identification purposes only. Always confirm fitment before ordering.