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BMW Cooling System Parts & Accessories for BMW 3 Series E30 (1984-1991)

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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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OEM Style Hose Clamps

T#:338927

Part#: HOSE-CLAMPS

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This product was last offered at the strikethrough price on
06-13-2026

Starting at $ 3.87 USD

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Sale - Save 3%

$ 3.99

This product was last offered at the strikethrough price on
06-13-2026

Starting at $ 3.87 USD

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Hose clamps for radiator hoses, coolant hoses, vacuum hoses, or intake hoses. These hose clamps are the same style as your OEM hoses with a smooth inside band to prevent cutting into the hose material.

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Race German Coolant Temperature Sender Adapter - M12x1.5

T#:6827887

Part#: RGCTSAM12

Ships in 3 Business Days

$ 35.99 USD

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Race German has devoted themselves to providing quality products for late model BMWs that cover both street and track applications. Race German has now grown their catalog to a wide variety of models and products geared towards keeping your car looking and running nice. For those looking to install an aftermarket coolant temp gauge, Race German has the perfect accessory for you! This adapter is machined out of aluminum and splices into your upper radiator hose. Perfect for use with Race German's E30 temperature gauge but has compatibility with a wire variety of other cars as well! Features: Tapped for M12x1.5 sized sensor 38mm diameter outlets which fit most BMW hoses Includes 2x hose clamps **Does not include temp sensor

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Race German Coolant Temperature Sender Adapter - 1/8NPT

T#:6827888

Part#: RGCTSA1/8NPT

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$ 35.99 USD

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Race German has devoted themselves to providing quality products for late model BMWs that cover both street and track applications. Race German has now grown their catalog to a wide variety of models and products geared towards keeping your car looking and running nice. For those looking to install an aftermarket coolant temp gauge, Race German has the perfect accessory for you! This adapter is machined out of aluminum and splices into your upper radiator hose. Perfect for use with Race German's E30 temperature gauge but has compatibility with a wire variety of other cars as well! Features: Tapped for 1/8NPT sized sensor 38mm diameter outlets which fit most BMW hoses Includes 2x hose clamps **Does not include temp sensor

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Race German Rethreaded Coolant Sensor

T#:2602235

Part#: 001-08-00-00-09

Ships in 2 Business Days

$ 50.00 USD

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$ 50.00 USD

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Often overlooked item for your 24V E30 swap, this sensor is the best option for a plug and play solution to have a working temperature gauge when doing a engine swap.

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

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T#:591800

Part#: 11537511580

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$ 37.99 USD

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Common point of failure in the cooling system.

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

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$ 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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Water Pump to Thermostat Cooling Hose - E30 E34 E28

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T#:6917

Part#: 11531287651

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$ 10.99 USD

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

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T#:19431

Part#: 17121712736

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$ 13.99 USD

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$ 13.99 USD

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VENT HOSE 17121712736 Manufactured by CRP

Radiator Fan Switch Plug - E30, E34, E36, E23, E32

T#:23947130

Part#: E30RADFANSP

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$ 17.99 USD

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$ 17.99 USD

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Thanks to its brittle plastic construction, this radiator fan switch plug is a common failure point. Race German offers this high-quality replacement to remedy this issue and get your car back to perfect operation.

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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

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$ 2.05 USD

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$ 2.05 USD

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

Bav Auto Expansion Tank Cap - E36 E46 E34 E39 E32 E38 E65 X3 X5 Z4 ...

T#:640208

Part#: 17117639022

In Stock

Sale - Save 15% $ 13.99

This product was last offered at the strikethrough price on
06-03-2026

$ 11.89 USD

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Qty

Sale - Save 15%

$ 13.99

This product was last offered at the strikethrough price on
06-03-2026

$ 11.89 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. From 1974 to 2019, Bavarian Autosport was one of the premier vendors for BMW and MINI auto parts. We are happy to preserve the Bav Auto legacy by continuing to carry their high-quality products into the future. All Bav Auto parts will remain unchanged in design and sourced from the same OEM suppliers to ensure long-lasting reliability. We trust these parts, accessories, and upgrades so confidently that we back every Bavarian Autosport branded component with a 2-year warranty.

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Thermostat Housing to Water Pipe Cooling Hose - E30 325e 325i ...

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T#:19253

Part#: 11531718982

Ships in 2 Business Days

$ 6.55 USD

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$ 6.55 USD

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This is the cooling system water hose that goes from the thermostat housing to the water pipe on E30 3 series.

This item fits the following BMWs:
1988-1991 E30 BMW 325e 325es 325i 325ic 325is 325ix

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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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$ 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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Race German Water Pump Stud Kit

T#:2602237

Part#: M20WPUMPSTUDKIT

Ships in 2 Business Days

$ 11.99 USD

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Replaces the factory bolts with studs and nuts to make changing water pumps a breeze Features 3 Class 45H Allen Head Studs 3 Copper Flange Nuts

OEM Rein Thermostat Coolant Hose - E30 M20

For vehicles with a production date up to 09/1987

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T#:583586

Part#: 13541289976

Ships in 2 Business Days

$ 8.81 USD

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$ 8.81 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.

OEM Rein Upper Radiator Hose - M42 E30 318i/is

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

T#:6953

Part#: 11531717622

In Stock at Vendor

$ 11.99 USD

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$ 11.99 USD

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Replace your cracked or leaking radiator hose to prevent further leaks and potentially catastrophic failure. This hose replaces the upper radiator hose that connects from the thermostat housing to the radiator inlet.

OEM Rein radiator hoses are always a perfect option when performing maintenance thanks to their high quality and longevity.

This item fits the following BMWs:
E30 BMW 318i, 318i Convertible, 318is

Fits BMW Engines including:
M42

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Rein Expansion Tank Cap - E30, E34

For vehicles with production date from 09/1987

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T#:592018

Part#: 17137639023

Ships in 4 Business Days

$ 14.99 USD

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$ 14.99 USD

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1.4 Bar pressure

Rein Coolant Hose - E28, E30, E34

For vehicles with production date from 09/1987

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T#:379671

Part#: 13541719966

Ships in 2 Business Days

$ 6.11 USD

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$ 6.11 USD

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Thermostat to throttle housing

OEM Rein Lower Radiator Hose - M42 E30 318i/is

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T#:6952

Part#: 11531717620

In Stock at Vendor

$ 16.99 USD

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$ 16.99 USD

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Replace your cracked or leaking radiator hose to prevent further leaks and potentially catastrophic failure. This hose replaces the lower radiator hose that connects from the radiator outlet to the thermostat housing.

OEM Rein radiator hoses are always a perfect option when performing maintenance thanks to their high quality and longevity.

This item fits the following BMWs:
E30 BMW 318i, 318i Convertible, 318is

Fits BMW Engines including:
M42

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Rein Lower Heater Hose - E30

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T#:379681

Part#: 11531714636

Ships in 2 Business Days

$ 7.99 USD

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$ 7.99 USD

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Heats & cools the throttle body

OEM Rein Coolant Hose - E30

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T#:379799

Part#: 13541719967

In Stock at Vendor

$ 14.06 USD

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$ 14.06 USD

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Fix that leak or replace that old line with this OE replacement!

O-RING

T#:580584

Part#: C32348

Ships in 3 Business Days

$ 3.99

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

$ 2.99 USD

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$ 2.99 USD

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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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$ 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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Water Pump O-Ring

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

T#:592886

Part#: 11511714519

Back Ordered

$ 9.17 USD

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$ 9.17 USD

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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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Victor Reinz Coolant Pipe Gasket

T#:19371

Part#: 11121726721

Back Ordered

$ 3.05 USD

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$ 3.05 USD

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GASKET ASBESTOS FREE 11121726721 Manufactured by Reinz

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