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

Clear BMW chassis

Please ensure your correct model is selected

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.

Sub-Categories

Sort By:

Meyle - Coolant Hose - Lower Right E46
5X Entries Into Our F80 M3 Sweepstakes
Meyle - Corporate Logo
T#:40478120
Part#: 11531436408
Ships on Oct 13, 2026
$ 32.99 USD
Free Shipping on orders $49 and up
Upgrade your BMW’s cooling system with a dependable solution that meets or exceeds OEM quality.
Coolant Flange - Rear/Engine Block
Fits European models only
5X Entries Into Our F80 M3 Sweepstakes
Meyle - Corporate Logo
T#:55533481
Part#: 11531708808
Ships on Oct 13, 2026
New Item
$ 9.99 USD
Free Shipping on orders $49 and up
$ 9.99 USD
Free Shipping on orders $49 and up
This Meyle Original-grade replacement coolant flange is the perfect solution for refreshing your BMW’s cooling plumbing back to factory-fresh operation.
Meistersatz - Corporate Logo
T#:379740
Part#: 13621433076
In Stock at Vendor
$ 15.99 USD
Free Shipping on orders $49 and up
Monitors coolant / oil temperature

Radiator Support Bracket
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:14122755
Part#: 17117514402
Back Ordered
$ 8.99

This product was last offered at the strikethrough price on
08-13-2026

$ 8.24 USD
Free Shipping on orders $49 and up
$ 8.24 USD
Free Shipping on orders $49 and up
Mounts to top of radiator bracket, 2 per vehicle.

Radiator Drain Plug With Housing
For vehicles with automatic transmission only
2X Entries Into Our F80 M3 Sweepstakes
URO - Corporate Logo
T#:593032
Part#: 17111437360
In Stock
$ 10.99 USD
Free Shipping on orders $49 and up
$ 10.99 USD
Free Shipping on orders $49 and up
This is the drain plug (adjustment screw) for automatic transmission equipped cars.
Auxiliary Fan Switch
Mounted in upper radiator hose, controls operation of auxiliary fan Mounted in lower radiator hose, controls operation of auxiliary fan
2X Entries Into Our F80 M3 Sweepstakes
URO - Corporate Logo
T#:376847
Part#: 13621433077
Back Ordered
$ 10.99 USD
Free Shipping on orders $49 and up
$ 10.99 USD
Free Shipping on orders $49 and up
Comes with related o-ring

MTC - Corporate Logo
T#:361005
Part#: 17111178412
Back Ordered
$ 2.03 USD
Free Shipping on orders $49 and up
This is the small lower rubber mount that goes on the bottom of the radiator. These mounts sit down into mount 17111723337. Fits left or right side - priced each
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.
Show More Show Less

BMW Radiator Hose Kit - 11537830715
2X Entries Into Our F80 M3 Sweepstakes
Rein - Corporate Logo
T#:46719180
Part#: CHK0376R
Ships in 3 Business Days
$ 43.99 USD
Free Shipping on orders $49 and up
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.
Show More Show Less