BMW Cooling System Parts & Accessories for BMW 3 Series E46 (1999-2005)

Bav Auto Thermostat With Aluminum Housing - M52TU M54

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T#:12544802

Part#: 11531437040

In Stock

Sale - Save 19% $ 104.99

This product was last offered at the strikethrough price on
05-03-2026

$ 84.99 USD

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$ 84.99 USD

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The plastic thermostat cover in your BMW is a known point of failure. Throughout years of repeated contact with hot coolant, the plastic can crack and cause massive coolant leaks and potential overheating. Eliminate one of the weak links in your cooling system with a replacement aluminum thermostat housing. By installing this aluminum unit, you have no worries as far as plastic housing cracks go

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Bav Auto Coolant Expansion Tank - E53 X5, E46, E83 X3

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T#:640496

Part#: 17137787039

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Sale - Save 18% $ 61.99

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05-03-2026

$ 50.99 USD

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$ 50.99 USD

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We have found that the expansion tanks should be replaced based on age as well as condition. Expansion tanks seem to have a lifespan of less than six years before they show signs of fatigue and wear. Pre-emptively replacing the expansion tank as part of an overall maintenance plan can prevent you from getting stranded from a sudden failure later on. 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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Bav Auto Expansion Tank Mounting Plate - E46 Non-M w/ Manual Trans ...

For vehicles with a manual transmission only

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T#:638088

Part#: 17111436250

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Sale - Save 20% $ 44.99

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05-03-2026

$ 35.99 USD

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This Bav Auto part is the mounting bracket from the radiator to the expansion tank on an E46 3 series with a Manual Transmission. 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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Bav Auto Heater Inlet Pipe - E46 E39 E53 E83 E85 Z3

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T#:638080

Part#: 11531705210

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Sale - Save 20% $ 40.99

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05-03-2026

$ 32.79 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. Replace yours with a brand new Bav Auto Heater inlet pipe to prevent catastrophic failure.

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Bavarian Autosport Water Pipe - E46 E39 Z4 Z3 (M52TU, M54)

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T#:638085

Part#: 11537502525

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This product was last offered at the strikethrough price on
05-03-2026

$ 40.79 USD

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This plastic water pipe is positioned directly underneath your intake manifold. Due to its plastic construction, it is notorious for catastrophic failure. Rapid cooling loss and overheating are both direct results of this failure, posing permanent and lasting damage to the engine.

Replace your cracked/broken coolant pipe with this high-quality Bavarian Autosport component to ensure long-term reliability and perfect fitment.

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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Bav Auto Expansion Tank Mounting Plate - E46 Non-M w/ Auto Trans ...

For vehicles with an automatic transmission only

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T#:638089

Part#: 17111436251

In Stock

Sale - Save 20% $ 45.99

This product was last offered at the strikethrough price on
05-03-2026

$ 36.79 USD

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$ 36.79 USD

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This Bav Auto part is the mounting bracket from the radiator to the expansion tank on E46 3 series and E85/E86 Z4 with an Automatic Transmission. 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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DO88 Racing Oil Cooler - E46 M3

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T#:13891842

Part#: OC150

In Stock at Vendor

$ 749.99 USD

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With a 185% bigger core volume, 50% bigger cooling area, and a 79% higher oil volume, this oil cooler compensates on no fronts. Built for the track but just as capable on the road, DO88's upgraded oil cooler for the E46 M3 gives you maximum performance and compromises nowhere.

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T#:15511839

Part#: 17111707817

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05-03-2026

$ 15.19 USD

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Connects the radiator to the expansion tank

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

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T#:640208

Part#: 17117639022

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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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DO88 Aluminum Radiator - Blue Hose - E46 M3

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T#:13891811

Part#: WC310B

Ships on Jul 30, 2026

$ 735.99 USD

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The team at DO88 has vigorously tested this radiator to deliver peak performance with the peace of mind of quality for your E46 M3. They guarantee reliability and endurance in all situations to let your car breathe better than before! Boasting a 17% increase in core volume, this upgrade is a no-brainer for petrol heads like us. Keeping core temperatures low eliminates the risk of heat soak leading to overheating giving you max performance at any given moment. no compromise has been made at DO88 leaving you with one of the best radiator options on the market!

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Bav Auto Temperature Sensor - BMW E39 E46 E9X E60 F01/02

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T#:639833

Part#: 13621433076

In Stock

Sale - Save 20% $ 14.99

This product was last offered at the strikethrough price on
05-03-2026

$ 11.99 USD

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This is the coolant temperature sensor used in many BMW models from the late-1990s to the mid-2010s. The engine computer relies on the coolant temp to set the fuel mapping for the engine. As the car warms up the computer changes the fuel mixture. If your car is running a bit rich (too much fuel) it could be because this sensor is failing and not sending the correct info to the computer. This sensor is located in a variety of places depending on the engine. But it's one of those easy replacement items 'while you're in there' when doing a water pump or thermostat replacement. 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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DO88 Coolant Hoses - Blue - E46 M3

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T#:13924830

Part#: DO88KIT70B

Back Ordered

$ 256.99 USD

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$ 256.99 USD

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Made out of high-quality silicone, these hoses display the highest levels of durability and quality. With three to five layers of armory the hoses are designed to withstand high pressure and heat for an extended period of time. The OE hoses are known to crack and leak but this hose kit eliminates any chance of that.

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BMW Cooling System Parts & Accessories for BMW 3 Series E46 (1999-2005)

Sub-Categories

Bav Auto Thermostat With Aluminum Housing - M52TU M54

Bav Auto Coolant Expansion Tank - E53 X5, E46, E83 X3

Bav Auto Expansion Tank Mounting Plate - E46 Non-M w/ Manual Trans ...

Bav Auto Heater Inlet Pipe - E46 E39 E53 E83 E85 Z3

Bavarian Autosport Water Pipe - E46 E39 Z4 Z3 (M52TU, M54)

Bav Auto Expansion Tank Mounting Plate - E46 Non-M w/ Auto Trans ...

DO88 Racing Oil Cooler - E46 M3

DO88 Racing Auxiliary Oil Cooler - E46 M3

Aluminum Radiator - Black - E46 M3

Coolant Hose Refresh Kit - Black - E46 320/323/325/328

DO88 Coolant Hoses - Black - E46 M3

Aluminum Radiator - Red Hose - E46 M3

Water Connection Pipe

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

DO88 Aluminum Radiator - Blue Hose - E46 M3

Bav Auto Temperature Sensor - BMW E39 E46 E9X E60 F01/02

DO88 Coolant Hoses - Blue - E46 M3

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