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BMW Cooling System Parts & Accessories for BMW 5 Series E34 (1987-1995)

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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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PENTOFROST NF 50/50 Antifreeze / Coolant Prediluted / Premixed - 1 G...

T#:34181293

Part#: 8114308

In Stock

$ 20.99 USD

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$ 20.99 USD

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Blue G11/G48 Coolant Pre-Mixed 50/50

Mahle-Behr Thermostat - 79Âº C - E34, E39, E52

T#:341209

Part#: 11537835558

In Stock at Vendor

$ 74.00

This product was last offered at the strikethrough price on
06-05-2026

$ 69.87 USD

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$ 69.87 USD

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Includes sealing o-ring

Rein Thermostat - 88ï¿½C - E30, E34, E36, Z3

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T#:591800

Part#: 11537511580

In Stock at Vendor

$ 37.99 USD

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$ 37.99 USD

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Common point of failure in the cooling system.

Automatic Transmission Cooler - E36 Z3 E34

T#:2069

Part#: 17201728770

Ships in 1 Business Day

$ 207.15

This product was last offered at the strikethrough price on
05-11-2026

$ 201.97 USD

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$ 201.97 USD

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This transmission fluid/oil cooler fits E36 318i 318is 318ti 323i 323is 325i 325is 328i 328is M3, E34 525i 530i 1993-1995 and Z3 1.9 2.3 2.5i 2.8 3.0i with automatic transmission.

This oil cooler fits the following BMWs:
1992-1998 E36 BMW 318i 318is 318ti 323is 325i 325is 328i 328is M3
1993-1995 E34 BMW 525i 525i Wagon
1994-1995 E34 BMW 530i 530i Wagon
1996-2002 Z3 BMW Z3 1.9 Z3 2.3 Z3 2.5i Z3 2.8 Z3 3.0ibr>

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Hella Radiator - Manual - E34

T#:363371

Part#: 17111737760

In Stock at Vendor

$ 687.60 USD

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$ 687.60 USD

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Replace your leaking radiator

Rein Radiator Hose - Upper - E32, E34

2X Entries For Our G87 M2 Sweepstakes! We Price Match - Give Us A Call or Chat!

T#:6960

Part#: 11531722682

In Stock at Vendor

$ 63.99 USD

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$ 63.99 USD

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BMW ENGINE WATER HOSE 11531722682.--

This item fits the following BMWs:
BMW 5 Series -535i
BMW 7 Series - 735i, 735iL

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OEM Rein Throttle Body Return Hose - E34 525i

For vehicles with a production date from 03/1991

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T#:379743

Part#: 11531738054

Ships in 3 Business Days

$ 61.99 USD

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$ 61.99 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.

Mahle-Behr Thermostat - 92C - E34, E36, E39

T#:12476

Part#: 11537511083

Ships in 8 Business Days

$ 29.99

This product was last offered at the strikethrough price on
05-22-2026

$ 27.65 USD

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$ 27.65 USD

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OEM BMW THERMOSTAT:115040

Thermostat - 80°C

T#:594727

Part#: 11531713040

Ships on Aug 6, 2026

$ 35.99 USD

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$ 35.99 USD

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The thermostat on your vehicle controls the flow of coolant based on temperature. When you just start your engine, the thermostat remains closed to accelerate the warm up process. After a few minutes, it opens up to allow the warm fluid to flow. If your vehicle is overheating but not blowing warm air from the heater, the problem is more than likely your thermostat.

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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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$ 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 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

$ 2.05 USD

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$ 2.05 USD

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This O-ring seals the thermostat to the cylinder head.

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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Qty

$ 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 Expansion Tank Hose - E12, E21, E23, E24, E28, E30, E32, E34 ...

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T#:19431

Part#: 17121712736

In Stock

$ 13.99 USD

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$ 13.99 USD

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VENT HOSE 17121712736 Manufactured by CRP

Water Pump to Thermostat Cooling Hose - E30 E34 E28

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T#:6917

Part#: 11531287651

In Stock

$ 10.99 USD

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Qty

$ 10.99 USD

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Replace your cracked or leaking coolant hose with this radiator coolant hose that goes from the waterpump to the thermostat on cars with the M20 engine. We recommend inspecting cooling system hoses for dry rot / cracks yearly.

This item fits the following BMWs:
1984-1991 E30 BMW 325e 325es 325i 325ic 325is 325ix
1982-1988 E28 BMW 528e
1989-1990 E34 BMW 525i

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Rein Coolant Bleeder Screw CHW1575 - Priced Each

2X Entries For Our G87 M2 Sweepstakes! We Price Match - Give Us A Call or Chat!

T#:591955

Part#: 17111712788

In Stock

$ 4.99 USD

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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 Water Hose (Right Outlet) - E32 E34

Also use- (Qty.) (1) 17 21 1 723 943 O-Ring. ¦ Right

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T#:593082

Part#: 17221728944

Ships in 3 Business Days

$ 28.99 USD

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$ 28.99 USD

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Transmission Oil Cooler to Water Manifold

OEM Rein Coolant Hose - E34 525i M20

2X Entries For Our G87 M2 Sweepstakes! We Price Match - Give Us A Call or Chat!

T#:6955

Part#: 11531720678

Ships in 1 Business Day

$ 11.99 USD

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$ 11.99 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.

This item fits the following BMWs:
BMW 5 Series - 525i, 525i Wagon

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OEM Rein Coolant Hose - E32 E34

For vehicles with production date from 03/1995

2X Entries For Our G87 M2 Sweepstakes! We Price Match - Give Us A Call or Chat!

T#:6970

Part#: 11531741405

Ships in 3 Business Days

$ 14.99 USD

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$ 14.99 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.

This item fits the following BMWs:
BMW 5 Series - 530i, 530i wagon /540i
BMW 7 Series - 740i, 740iL

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Rein Coolant Hose - E28, E30, E34

2X Entries For Our G87 M2 Sweepstakes! We Price Match - Give Us A Call or Chat!

T#:379671

Part#: 13541719966

Ships in 1 Business Day

$ 6.11 USD

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Qty

$ 6.11 USD

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Thermostat to throttle housing

OEM Rein Lower Radiator Hose - E34 525i

2X Entries For Our G87 M2 Sweepstakes! We Price Match - Give Us A Call or Chat!

T#:6962

Part#: 11531722852

Ships in 1 Business Day

$ 12.99 USD

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$ 12.99 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 Expansion Tank Cap - E30, E34

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T#:592018

Part#: 17137639023

Ships in 3 Business Days

$ 14.99 USD

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Qty

$ 14.99 USD

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1.4 Bar pressure

Coolant Expansion Tank With Cap - 17111712835

T#:46616014

Part#: EPK0012

Back Ordered

$ 29.99 USD

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$ 29.99 USD

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The coolant expansion tank provides a place for excess fluid as coolant expands and contracts with temperature changes. Constant exposure to these extremes can cause the tank to crack, break, or suffer damage to its nipples or mounting points. To keep your cooling system sealed and functioning properly, any damaged tank should be replaced.

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Rein Heater Hose - E32, E34

2X Entries For Our G87 M2 Sweepstakes! We Price Match - Give Us A Call or Chat!

T#:20514

Part#: 64211390935

Back Ordered

$ 12.99 USD

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Qty

$ 12.99 USD

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HOSE F WATER VALVE AND LEFT 64211390935 Manufactured by CRP

Rein Thermostat 80C - E30 325e, E28 535i, E24 633CSi

2X Entries For Our G87 M2 Sweepstakes! We Price Match - Give Us A Call or Chat!

T#:34114243

Part#: 11531710953

In Stock

$ 19.99 USD

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Qty

$ 19.99 USD

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Thermostat 80C is a crucial component for controlling the temperature in BMW engines, ensuring optimal performance and protection. Designed to open at 80°C, this thermostat helps your engine reach its ideal operating temperature quickly while preventing overheating. Engineered specifically for BMW vehicles, the Thermostat 80C ensures precise temperature regulation, enhancing both engine efficiency and longevity. Available at Turner Motorsport, this direct-fit replacement offers easy installation and reliable performance.

Designed for BMW engines for a perfect fit
Opens at 80°C to regulate coolant flow and maintain optimal temperature
Prevents overheating and improves engine efficiency
Manufactured from high-quality, durable materials for long-lasting use
Direct-fit replacement ensures hassle-free installation
Enhances overall engine performance and longevity

The Thermostat 80C from Turner Motorsport is the perfect choice for BMW owners looking to maintain optimal engine temperature, ensuring smooth operation and extending the life of their vehicle.

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Behr Radiator - E34

T#:1195792

Part#: 17111723467

Back Ordered

$ 273.99

This product was last offered at the strikethrough price on
05-07-2026

$ 265.99 USD

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Qty

$ 265.99 USD

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OE replacement radiator

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