Rein BMW Cooling System Parts & Accessories for BMW 5 Series E39 (1996-2003)

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The cooling system is arguably the weakest point in numerous BMWs. If you drive an aging BMW or plan on taking your car to the track like we do, we recommend beefing up your cooling system before going to the track. Generally, the main components in your cooling system that are prone to failure include the following: expansion tank, factory hoses, water pump, thermostat, fan (especially if your vehicle comes factory with a clutch fan), and radiator. Factory BMW expansion tanks are plastic and prone to either breaking off at connection points or combusting. As factory rubber hoses age they either crack or break over time - we offer silicone cooling hose upgrades for most applications to avoid future failures. If you have an older vehicle, your water pump likely comes from the factory with a plastic impeller - we offer upgraded water pumps with metal impellers that are far more reliable. Newer model BMWs utilize electric water pumps - BMW spent millions of dollars engineering these water pumps, but they fail so often that we recommend replacing at 60,000 mile service intervals to avoid being stranded on the side of the road. In terms of thermostats, we offer various upgraded thermostats for racing applications. If your BMW utilizes a clutch fan from the factory, we have several options available in terms of universal electric fans - we recommend replacing these to avoid sending brittle plastic fan blades through your hood. For radiators, we recommend swapping out your radiator for one that does not use plastic connection points like your factory radiator.

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BMW M52 M54 Water Pipe
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T#:594294
Part#: 11537502525
In Stock
$ 55.99 USD
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BMW M52 M54 Water Pipe is an essential replacement part designed to ensure long-term reliability and optimal performance for your BMW's cooling system. Engineered to replace cracked or broken coolant pipes, this high-quality water pipe from Turner Motorsport guarantees a perfect fit and dependable service. Investing in this replacement pipe helps prevent overheating and potential engine damage, maintaining your vehicle's performance and longevity.

  • Reliable replacement: Designed to replace cracked or broken coolant pipes for improved engine cooling.
  • Optimal fitment: Engineered to ensure a perfect fit and seamless installation.
  • Durable construction: Built with high-quality materials to withstand engine temperatures and environmental conditions.
  • Preventative maintenance: Helps avoid overheating and potential engine damage by ensuring a reliable coolant flow.
  • Vehicle compatibility: Specifically designed for BMW M52 and M54 engine models.

Upgrade your BMW’s cooling system with the BMW M52 M54 Water Pipe from Turner Motorsport for enhanced reliability and performance.

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Heater Inlet Pipe
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T#:594330
Part#: 11531705210
In Stock
$ 41.99 USD
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This is the plastic heater inlet pipe that connects the cylinder head to the heater inlet on cars with the M52 or M54 engine.The plastic on this hose becomes brittle over time and eventually leads to failure.
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OEM Coolant Return Pipe from Water Pump Hose to Transmission Cooler T...
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T#:6945
Part#: 11531711384
In Stock at Vendor
$ 68.99 USD
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$ 68.99 USD
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This is the cooling system return hose that goes from the automatic transmission cooling thermostat to the hose that comes off the lower water pump outlet.1999-2003 E39 BMW 540i
1999-2001 E38 BMW 740i 740il
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E39 Upper Radiator Hose - E39 525i 528i 530i
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T#:4473
Part#: 11531705223
Ships in 1-2 days
$ 45.99 USD
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This cooling hose goes from the upper radiator port to the water pump. It includes a new bleed screw.

This item fits the following BMWs:
1999-2003 E39 BMW 525i 528i 530i
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OEM Rein Coolant Hose - E38 E39 M62 4.4L
For vehicles with production date from 09/1998
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T#:375752
Part#: 11537511207
In Stock at Vendor
$ 25.80 USD
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$ 25.80 USD
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Over time, coolant hoses begin to get brittle and are susceptible to cracking and splitting. Replace your cracked or leaking coolant hose to prevent further leaks and potentially catastrophic failure.
Rein Radiator Hose - Lower - E39
For vehicles with production date from 09/1998
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T#:341242
Part#: 11531705224
Ships in 1 Business Day
$ 37.99 USD
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$ 37.99 USD
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Includes retaining clips

Expansion Tank Hose
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T#:375747
Part#: 11531438632
Ships in 1 Business Day
$ 24.99 USD
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Coolant Expansion Tank
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T#:591959
Part#: 17111741167
In Stock
$ 69.99 USD
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$ 69.99 USD
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Plastic has a limited lifespan - replace every 80,000 miles

BMW E39 Coolant Expansion Tank
For vehicles with production date from 09/1998
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T#:388645
Part#: 17111436381
In Stock
$ 87.99 USD
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$ 87.99 USD
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BMW E39 Coolant Expansion Tank is an essential component designed to maintain the proper coolant level in your vehicle's cooling system. Manufactured with high-quality materials, this expansion tank ensures reliable performance and durability, preventing engine overheating by accommodating the expansion of coolant as it heats up. The kit includes a level sensor and cap, providing everything needed for a seamless installation. This expansion tank is specifically engineered to meet the exact specifications of your BMW E39, offering a perfect fit and optimal functionality.

  • Complete Kit: Includes level sensor and cap for easy installation.
  • High-Quality Construction: Built with durable materials for long-lasting performance.
  • Prevents Overheating: Helps manage coolant expansion, ensuring engine protection.
  • Exact Fit: Designed to meet the precise specifications of your BMW E39.
  • Enhanced Reliability: Ensures proper coolant level maintenance for optimal cooling system function.
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Thermostat With Housing
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T#:582356
Part#: 11537509227
Ships in 3 Business Days
$ 89.99 USD
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$ 89.99 USD
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Stop leaks before they start with this new Thermostat With Housing from Rein.
BMW Radiator Hose Kit - 11537505229
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T#:46719191
Part#: CHK0008P
Ships in 3 Business Days
$ 61.99 USD
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Keep your cooling system sealed, strong, and ready for anything with this Rein radiator hose kit—your all-in-one fix for cracked, leaking, or worn factory hoses. Years of heat, pressure, and age can cause rubber to weaken, split, or swell, setting the stage for coolant leaks and potential overheating. Rein hoses are engineered to meet or exceed OEM standards, built from premium, heat-resistant materials that can take on extreme temperatures and system pressures without faltering. Each hose features factory-correct bends, fittings, and diameters for an exact, hassle-free installation—no cutting or forcing required. Whether you’re tackling a full cooling system refresh or chasing down a small coolant leak, this Rein kit provides everything needed to restore confidence and performance under the hood. Why choose this Rein radiator hose kit: Factory-level precision – Direct-fit replacements that deliver OEM-quality reliability. Built to last – Resists cracking, swelling, and chemical damage from daily heat cycling. Confidence restored – Prevents coolant loss, overheating, and on-road breakdowns. All-in-one upgrade – Includes upper and lower hoses for a complete system refresh. If keeping your BMW’s cooling system running tight and trouble-free is the goal, Rein brings the dependable quality and fitment you can count on—engineered to perform just like factory, mile after mile.
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Rein Water Pump O-Ring (Small) - E32, E34, E38, E39
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T#:379680
Part#: 11531710055
In Stock
$ 2.03 USD
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When it comes time to replace the water pump, be sure to replace all the O-Rings associated with it to ensure that your car stays leak free. If you are experiencing leaking issues, be sure to inspect these rings, as they might have worn down. This specific ring is used when replacing water pump on cooling pipe to the water accumulator. There are two per car.
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Rein Coolant Bleeder Screw CHW1575 - Priced Each
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T#:591955
Part#: 17111712788
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$ 4.99 USD
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Coolant Bleeder Screw is a critical component for maintaining your BMW’s cooling system. Designed to release trapped air from the coolant lines, this screw ensures efficient coolant flow and prevents overheating. Specifically engineered for BMW models, it enhances the overall performance and longevity of your engine by maintaining proper temperature regulation. Comes with O-Ring.
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Rein Thermostat O-Ring (60 X 3.5 mm) - E28 E30 E32 E34 E36 E39 Z3 E23...
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T#:591144
Part#: 11531265084
In Stock at Vendor
$ 2.05 USD
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This O-ring seals the thermostat to the cylinder head.
OEM Rein Expansion Tank Cap - BMW E32 E34 E36 E38 E39 E46 & More ...
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T#:340541
Part#: 17111742231
In Stock
$ 17.99 USD
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This radiator expansion tank cap is used most BMW's from 1991-2006. It is a common failure item. When this item fails, it cannot hold pressure which results in your BMW overheating. If you are overhauling your coolant system, now is the time to consider preventative replacing this cap. It is also referred to as the coolant reservoir cap.
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Rein Expansion Tank Hose - E39
For vehicles with production date from 09/1998
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T#:375748
Part#: 11531438633
In Stock
$ 18.99 USD
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$ 18.99 USD
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Runs from the expansion tank to auxiliary water pump

Rein Expansion Tank Hose - E31, E38, E39
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T#:375756
Part#: 11531741404
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$ 8.45 USD
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Connects the expansion tank to the radiator
OE Rein Lower Radiator Hose - E39 540i, E38 740i/IL 1996-1998 ...
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T#:374352
Part#: 11531741409
Ships in 3 Business Days
$ 17.99 USD
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This item fits the following BMWs:    
1997-1998   E39 BMW   540i  
1996-1998   E38 BMW   740i 740il 

OEM BMW Engine Return Hose 11531744054
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T#:6975
Part#: 11531744054
In Stock at Vendor
$ 19.99 USD
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OEM BMW ENGINE RETURN HOSE 11531744054.--

This item fits the following BMWs:
BMW 5 Series - 528i, 528i Wagon

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OE Rein Upper Radiator Hose - E39 540i, E38 740i/IL 1996-1998 ...
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T#:6976
Part#: 11531745595
Ships in 3 Business Days
$ 16.99 USD
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ENGINE WATER HOSE 11531745595.--

This item fits the following BMWs:
BMW 5 Series - 540i, 540i Wagon
BMW 7 Series - 740i, 740iL

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BMW Radiator Hose - 11531705224
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T#:46719192
Part#: CHK0005
In Stock at Vendor
$ 43.99 USD
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Keep your cooling system sealed, strong, and ready for anything with this Rein radiator hose—your all-in-one fix for cracked, leaking, or worn factory hoses. Years of heat, pressure, and age can cause rubber to weaken, split, or swell, setting the stage for coolant leaks and potential overheating. Rein hoses are engineered to meet or exceed OEM standards, built from premium, heat-resistant materials that can take on extreme temperatures and system pressures without faltering. Each hose features factory-correct bends, fittings, and diameters for an exact, hassle-free installation—no cutting or forcing required. Whether you’re tackling a full cooling system refresh or chasing down a small coolant leak, this Rein kit provides everything needed to restore confidence and performance under the hood. Why choose this Rein radiator hose: Factory-level precision – Direct-fit replacements that deliver OEM-quality reliability. Built to last – Resists cracking, swelling, and chemical damage from daily heat cycling. Confidence restored – Prevents coolant loss, overheating, and on-road breakdowns. All-in-one upgrade – Includes upper and lower hoses for a complete system refresh. If keeping your BMW’s cooling system running tight and trouble-free is the goal, Rein brings the dependable quality and fitment you can count on—engineered to perform just like factory, mile after mile.
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OEM Rein Upper Radiator Hose - E39 528i (up to 09/1998)
For vehicles with production date up to 09/1998
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T#:349033
Part#: 11531740832
Ships in 1 Business Day
$ 17.99 USD
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$ 17.99 USD
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Over time, coolant hoses begin to get brittle and are susceptible to cracking and splitting. Replace your cracked or leaking coolant hose to prevent further leaks and potentially catastrophic failure.
Rein O-RING 14.4X3.0 - E38, E39
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T#:379805
Part#: 11537501777
Ships in 3 Business Days
$ 6.99 USD
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$ 6.99 USD
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OEM Rein Lower Radiator Hose - E39 528i
For vehicles with production date up to 09/1998
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T#:349032
Part#: 11531740481
Ships in 1 Business Day
$ 14.99 USD
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$ 14.99 USD
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Runs from the radiator to the thermostat housing. Over time, coolant hoses begin to get brittle and are susceptible to cracking and splitting. Replace your cracked or leaking coolant hose to prevent further leaks and potentially catastrophic failure.
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Rein Thermostat Assembly E38 740iL
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T#:34114233
Part#: 11531437526
Ships in 1 Business Day
$ 68.99 USD
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Regulates Engine coolant temperature. Comes with aluminum housing, O-ring, and sensor.
Rein Coolant Overflow Hose
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T#:19458
Part#: 17111427156
Ships on Jul 15, 2026
$ 5.99 USD
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Rein Coolant Overflow Hose is designed to meet the highest standards of performance and durability for your vehicle's cooling system. This high-quality hose ensures the proper transfer of excess coolant from the engine to the overflow reservoir, preventing overheating and ensuring optimal engine performance. Manufactured from reinforced rubber materials, the Rein Coolant Overflow Hose guarantees long-lasting reliability and precise fitment for various vehicle makes and models. It’s the perfect upgrade or replacement for worn-out hoses in any cooling system.

Available through Turner Motorsport, this coolant overflow hose is rigorously tested to withstand extreme temperatures, pressures, and daily use. If you’re looking to maintain or improve your car's cooling efficiency, the Rein Coolant Overflow Hose is an essential component.

  • Precision engineered for a perfect fit
  • Manufactured from durable, reinforced rubber
  • Designed to withstand high temperatures and pressures
  • Improves cooling system efficiency and prevents overheating
  • Easy installation with OE-spec dimensions
  • Available at Turner Motorsport, trusted for automotive parts

Enhance your vehicle's performance and reliability by replacing your old coolant hose with the Rein Coolant Overflow Hose today.

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Rein Coolant Hose - E39
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T#:379777
Part#: 64218391003
Special Order: No Guaranteed ETA
$ 31.99 USD
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$ 31.99 USD
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Hose that runs from the engine block to the water valve. Over time, coolant hoses begin to get brittle and are susceptible to cracking and splitting. Replace your cracked or leaking coolant hose to prevent further leaks and potentially catastrophic failure.
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BMW Coolant Expansion Tank With Cap
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T#:46616009
Part#: EPK0013
Back Ordered
$ 64.99 USD
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The coolant expansion tank in your vehicle gives additional fluid a place to go after expansion and contraction from temperature change. Because it is subjected to such drastic changes on a regular basis, it can often crack or break. You want to keep all the coolant in your vehicle in the cooling system. If your tank has experienced damage such as cracking, nipples breaking off, or mounting point damage, you will need to replace it. This replacement will fit perfectly and provide the same heating and cooling characteristics as an original unit. When replacing, be sure to have some extra coolant. Check ECS Tuning's website for a wide variety of coolants specifically designed for your car. Most German vehicles require specialized coolant. Be sure to pick up the proper coolant when refilling to avoid damage or premature corrosion.
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