DO88 BMW Cooling System Parts & Accessories for BMW 3 Series E46 (1999-2005)

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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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DO88 Racing Oil Cooler - E46 M3
affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
DO88 - Corporate Logo
T#:13891842
Part#: OC150
In Stock at Vendor
$ 749.99 USD
Free Shipping on orders $49 and up
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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DO88 Racing Auxiliary Oil Cooler - E46 M3
affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
DO88 - Corporate Logo
T#:13891851
Part#: OC120E46
In Stock
$ 646.99 USD
Free Shipping on orders $49 and up
This racing oil cooler shines in low-pressure situations, for example, power steering oil cooling or gearbox oil cooling. This oil cooler comes ready to install with hardware.
Aluminum Radiator - Black - E46 M3
affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
DO88 - Corporate Logo
T#:13891809
Part#: WC310S
In Stock at Vendor
$ 735.99 USD
$ 735.99 USD
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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Coolant Hose Refresh Kit - Black - E46 320/323/325/328
affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
DO88 - Corporate Logo
T#:14155765
Part#: KIT219S
Ships on Jun 24, 2026
$ 360.99 USD
Free Shipping on orders $49 and up
These hoses are entirely manufactured in high-quality silicone for best finish and durability. With three to five layers of armory, depending of the inner diameter, the hoses withstand high-pressure rates and high temperatures for a long time. The original hoses are manufactured in rubber that not seldom cracks from age. This is the durable solution for you that in addition improves the looks!
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Aluminum Radiator - Red Hose - E46 M3
affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
DO88 - Corporate Logo
T#:13891810
Part#: WC310R
Ships on Jun 24, 2026
$ 735.99 USD
$ 735.99 USD
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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DO88 Coolant Hoses - Black - E46 M3
affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
DO88 - Corporate Logo
T#:13924829
Part#: DO88KIT70S
Ships on Jun 24, 2026
$ 256.99 USD
Free Shipping on orders $49 and up
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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DO88 Aluminum Radiator - Blue Hose - E46 M3
affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
DO88 - Corporate Logo
T#:13891811
Part#: WC310B
Ships on Jun 24, 2026
$ 735.99 USD
$ 735.99 USD
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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DO88 Coolant Hoses - Blue - E46 M3
affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
DO88 - Corporate Logo
T#:13924830
Part#: DO88KIT70B
Back Ordered
$ 256.99 USD
Free Shipping on orders $49 and up
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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