HomeBelts and Cooling > Thermostat and HousingRein CTN0045 Engine Coolant Thermostat
Part #: CTN0045

Rein CTN0045 Engine Coolant Thermostat

⚙️ 33 vehicles fit this part
🔍
Select your vehicle to confirm fitment
Verify this part fits before purchasing — free returns if it doesn't
$20.36Free Shipping
🚚Free ShippingNo Cost to Continental U.S.
🔄Free Returns*Wrong fit? No cost
🛡️60-Day ReturnsMoney back guarantee
*Free return shipping only qualifies if our fitment verification tool is used.
🔥
✅ In Stock · Ready To Ship Most orders ship same-day if ordered before 1pm CST.
OE Direct Replacement — Bolt-on fit, no modifications needed
🚗Fitment: BMW, 318i, 318is, 320i, 325i, 325is, 328i, 328is, 525i, 525iT, M3, and Z3
🔄Easy Returns — Return within 60 days for a full refund
🚚Fast Shipping — Most orders ship same business day before 1pm CST

Reliable Engine Coolant Thermostat for BMW Models

The Rein CTN0045 engine coolant thermostat is designed to meet original equipment specifications, ensuring precise temperature regulation for your BMW 318i, 320i, 325i, 328i, 525i, M3, and Z3 models. This application-specific thermostat helps maintain optimal engine performance and efficiency.

Key Features of Rein CTN0045 Thermostat

  • Matches original equipment design specifications for accurate fit and function
  • Includes all necessary gaskets or seals required for installation
  • Manufactured to strict engineering standards in Germany
  • Thermostat set to 88 degrees Celsius to maintain optimal engine running temperature
  • Compact dimensions: 3.0 inches length, 3.0 inches width, and 2.0 inches height

Detailed Product Description

The Rein CTN0045 thermostat insert is engineered as a direct replacement for BMW vehicles including the 318i, 318is, 320i, 325i, 325is, 328i, 328is, 525i, 525iT, M3, and Z3. Manufactured in Germany, this thermostat is designed to regulate coolant flow by opening at 88 degrees Celsius, which helps maintain the engine’s optimal operating temperature. The product includes all necessary gaskets or seals to ensure a proper seal during installation, reducing the risk of leaks. Its precise engineering and adherence to original equipment specifications make it a reliable choice for maintaining your BMW’s cooling system performance.

Common Applications and Issues Addressed

  • Prevents engine overheating by regulating coolant flow
  • Helps avoid poor engine performance caused by incorrect coolant temperature
  • Reduces risk of coolant leaks with included gaskets and seals
  • Maintains consistent engine temperature for fuel efficiency
  • Replaces faulty or worn thermostats in BMW 3 Series and 5 Series models

Installation Notes and Tips

While the Rein CTN0045 thermostat includes all necessary gaskets and seals, installation hardware is not included. It is recommended to consult a professional mechanic or refer to the vehicle’s service manual for proper installation procedures. Ensure the engine is cool before removal and replacement to avoid injury. Proper installation will help maintain the integrity of the cooling system and prevent leaks.

Quality Assurance and Warranty

Manufactured to strict engineering standards in Germany, the Rein CTN0045 thermostat insert is built for durability and reliable performance. It meets original equipment specifications to ensure compatibility and function. Warranty details should be confirmed with the point of purchase or manufacturer documentation.

BrandRein
Part NumberCTN0045
Application TypeApplicationspecific
Bullet Point 1Matches original equipment design specifications
Bullet Point 2All gaskets or seals necessary for installation are supplied with
Bullet Point 3Manufactured to strict engineering standards/specifications in ma
Bullet Point 4Thermostat set to 88 degrees celsius to maintain optimal running
Container TypeBx
Country of OriginDe
Installation Instructions IncludedNo
Is the Installation Hardware IncludedNo
Item Height2.0000
Item Length3.0000
Item Level GTIN888544069833
Item Qty1
Item Quantity Size1
Item Quantity Size UOMEa
Item UOMEa
Item Weight0.2550
Item Weight Unit UOMLb
Item Width3.0000
Product Desc Extended 240Rein oe quality thermostat inserts are designed to be direct repl
Product Desc Invoice 40Rein thermostat insert
Product Desc Long 80Rein oe quality thermostat insert
Product Desc Short 20Thermostat insert

This part fits 33 vehicles. Search below:

YearMakeModelBody TypeLitersCylindersPositionNotes
2000BMWZ33.2LL6N/A
1999BMWM33.2LL6N/A
1999BMWZ33.2LL6N/A
1998BMWM33.2LL6N/A
1998BMWZ33.2LL6N/A
1997BMWM33.2LL6N/A
1996BMW328i2.8LL6N/A88c, To 12/95
1996BMW328is2.8LL6N/A88c, To 12/95
1996BMWM33.2LL6N/A
1995BMW320i2.0LL6N/A88c
1995BMW325i2.5LL6N/A88c
1995BMW325is2.5LL6N/A88c
1995BMW525i2.5LL6N/A88c
1995BMWM33.0LL6N/A88c
1994BMW320i2.0LL6N/A88c
1994BMW325i2.5LL6N/A88c
1994BMW325is2.5LL6N/A88c
1994BMW525i2.5LL6N/A88c
1994BMWM33.0LL6N/A88c
1993BMW320i2.0LL6N/A88c
1993BMW325iSedan2.5LL6N/A88c
1993BMW325is2.5LL6N/A88c
1993BMW525i2.5LL6N/A88c
1993BMW525iT2.5LL6N/A88c
1992BMW318iConvertible1.8LL4N/A
1992BMW318is1.8LL4N/A
1992BMW320i2.0LL6N/A88c
1992BMW325iSedan2.5LL6N/A88c
1992BMW325is2.5LL6N/A88c
1992BMW525i2.5LL6N/A88c
1991BMW318i1.8LL4N/A
1991BMW318is1.8LL4N/A
1991BMW525i2.5LL6N/A88c

* 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:

1153172100211537511580

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