September 20, 2023

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Auxiliary Coolant Pump Replacement – BMW B46/B48 Turbo 4 Cyl. Engine

There can be several different auxiliary coolant pumps in BMW engines, but this article deals specifically with the one that cools the turbocharger unit in B46/B48 4-cylinder engines. The turbocharger in your BMW is subjected to brutal heat conditions - the temperature of exhaust gases leaving the unit can be in excess of 1000 degrees F. If not cooled properly, the turbocharger will fail. The auxiliary turbocharger coolant pump helps keep the temperature within acceptable operating limits and should be replaced immediately upon any signs of malfunction. This article gives detailed step-by-step instructions on replacing the auxiliary turbocharger coolant pump in BMW B46/B46 engines.

Not sure which engine you have in your BMW? Use our engine finder tool to easily identify it!

Possible Symptoms: Turbocharger overheating, severe decrease in performance, turbocharger failure

This repair can be used on the following BMW models:

2013

225i Active Tourer, Cooper S 3 doors,

2014

220i Active Tourer, 220i Gran Tourer, 225i Active Tourer, 225iX Active Tourer, 320i Touring, 320iX Touring, 330i Touring, 730Li Sedan, 730i Sedan, Cooper S 3 doors, Cooper S 5 doors, Cooper S Clubman, Cooper S Convertible, JCW 3 doors, X1 20Li SUV, X1 20LiX SUV, X1 20i SUV, X1 20iX SUV, X1 25LiX SUV, X1 25iX SUV, X1 28i SUV, X1 28iX SUV,

2015

2016

120i 3 doors, 120i 5 doors, 120i Sedan, 125i 3 doors, 125i 5 doors, 125i Sedan, 220i Active Tourer, 220i Convertible, 220i Coupe, 220i Gran Tourer, 225i Active Tourer, 225iX Active Tourer, 230i Convertible, 230i Coupe, 230iX Convertible, 230iX Coupe, 320Li Sedan, 320LiX Sedan, 320i Gran Turismo, 320i Touring, 320iX Gran Turismo, 320iX Touring, 330Li Sedan, 330LiX Sedan, 330e Sedan, 330i Gran Turismo, 330i Sedan, 330i Touring, 330iX Gran Turismo, 330iX Sedan, 330iX Touring, 420i Convertible, 420i Coupe, 420i Gran Coupe, 420iX Coupe, 420iX Gran Coupe, 430i Convertible, 430i Coupe, 430i Gran Coupe, 430iX Convertible, 430iX Coupe, 430iX Gran Coupe, 520i 1.6 Sedan, 520i Sedan, 520i Touring, 525Li Sedan, 528Li Sedan, 530Le Sedan, 530Li Sedan, 530LiX Sedan, 530e Sedan, 530eX Sedan, 530i Sedan, 530i Touring, 530iX Sedan, 530iX Touring, 630i Gran Turismo, 730Li Sedan, 730i Sedan, 740Le Sedan, 740LeX Sedan, 740e Sedan, 740eX Sedan, Cooper S ALL4 Clubman, Cooper S ALL4 Countryman, Cooper S 3 doors, Cooper S 5 doors, Cooper S Clubman, Cooper S Convertible, Cooper S Countryman, JCW ALL4 Clubman, JCW ALL4 Countryman, JCW 3 doors, JCW Convertible, X1 20Li SUV, X1 20LiX SUV, X1 20i SUV, X1 20iX SUV, X1 25LiX SUV, X1 25iX SUV, X1 28i SUV, X1 28iX SUV, X2 20i SAC, X2 28iX SAC, X3 20i 1.6 SUV, X3 20i SUV, X3 20iX (TR51) SUV, X3 30iX (TR91) SUV, X3 30iX (TR92) SUV, X3 30iX SUV,

2017

120i 3 doors, 120i 5 doors, 120i Sedan, 125i 3 doors, 125i 5 doors, 125i Sedan, 220i Active Tourer, 220i Convertible, 220i Coupe, 220i Gran Tourer, 225i Active Tourer, 225iX Active Tourer, 230i Convertible, 230i Coupe, 230iX Convertible, 230iX Coupe, 320Li Sedan, 320LiX Sedan, 320i Gran Turismo, 320i Sedan, 320i Touring, 320iX Gran Turismo, 320iX Touring, 330Li Sedan, 330LiX Sedan, 330e Sedan, 330i Gran Turismo, 330i Sedan, 330i Touring, 330iX Gran Turismo, 330iX Sedan, 330iX Touring, 420i Convertible, 420i Coupe, 420i Gran Coupe, 420iX Coupe, 420iX Gran Coupe, 430i Convertible, 430i Coupe, 430i Gran Coupe, 430iX Convertible, 430iX Coupe, 430iX Gran Coupe, 520i 1.6 Sedan, 520i Sedan, 520i Touring, 525Li Sedan, 528Li Sedan, 530Le Sedan, 530Li Sedan, 530LiX Sedan, 530e Sedan, 530eX Sedan, 530i Sedan, 530i Touring, 530iX Sedan, 530iX Touring, 630i Gran Turismo, 730Li Sedan, 730i Sedan, 740Le Sedan, 740LeX Sedan, 740e Sedan, 740eX Sedan, Cooper S ALL4 Clubman, Cooper S ALL4 Countryman, Cooper S 3 doors, Cooper S 5 doors, Cooper S Clubman, Cooper S Convertible, Cooper S Countryman, JCW ALL4 Clubman, JCW ALL4 Countryman, JCW 3 doors, JCW Convertible, X1 20Li SUV, X1 20LiX SUV, X1 20i SUV, X1 20iX SUV, X1 25LiX SUV, X1 25iX SUV, X1 28i SUV, X1 28iX SUV, X2 20i SAC, X2 20iX SAC, X2 25iX SAC, X2 28i SAC, X2 28iX SAC, X2 M35iX SAC, X3 20i (TR12) SUV, X3 20i (TR16) SUV, X3 20i 1.6 SUV, X3 20i SUV, X3 20iX (TR51) SUV, X3 20iX (TR52) SUV, X3 20iX (TR55) SUV, X3 20iX (TR56) SUV, X3 25iX SUV, X3 28iX SUV, X3 30i SUV, X3 30iX (TR91) SUV, X3 30iX (TR92) SUV, X3 30iX (TR95) SUV, X3 30iX (TR96) SUV, X3 30iX SUV, X4 20iX SAC, X4 30iX SAC, Z4 20i Roadster, Z4 30i Roadster,

2018

120i 3 doors, 120i 5 doors, 120i Sedan, 125i 3 doors, 125i 5 doors, 125i Sedan, 220i Active Tourer, 220i Convertible, 220i Coupe, 220i Gran Tourer, 225i Active Tourer, 225iX Active Tourer, 228iX Gran Coupe, 230i Convertible, 230i Coupe, 230iX Convertible, 230iX Coupe, 320Li Sedan, 320LiX Sedan, 320i 1.6 Sedan, 320i Gran Turismo, 320i Sedan, 320i Touring, 320iX Gran Turismo, 320iX Sedan, 320iX Touring, 325Li Sedan, 325LiX Sedan, 325i Sedan, 330Li Sedan, 330LiX Sedan, 330e Sedan, 330i Gran Turismo, 330i Sedan, 330i Touring, 330iX Gran Turismo, 330iX Sedan, 330iX Touring, 420i Convertible, 420i Coupe, 420i Gran Coupe, 420iX Coupe, 420iX Gran Coupe, 430i Convertible, 430i Coupe, 430i Gran Coupe, 430iX Convertible, 430iX Coupe, 430iX Gran Coupe, 520i 1.6 Sedan, 520i Sedan, 520i Touring, 525Li Sedan, 530Le Sedan, 530Li Sedan, 530LiX Sedan, 530e Sedan, 530eX Sedan, 530i Sedan, 530i Touring, 530iX Sedan, 530iX Touring, 630i Gran Turismo, 730Li Sedan, 730i Sedan, 740Le Sedan, 740LeX Sedan, 740e Sedan, 740eX Sedan, Cooper S ALL4 Clubman, Cooper S ALL4 Countryman, Cooper S 3 doors, Cooper S 5 doors, Cooper S Clubman, Cooper S Convertible, Cooper S Countryman, JCW ALL4 Clubman, JCW ALL4 Countryman, JCW 3 doors, JCW Convertible, M135iX 5 doors, M235iX Gran Coupe, X1 20Li SUV, X1 20LiX SUV, X1 20i SUV, X1 20iX SUV, X1 25Li SUV, X1 25LiX SUV, X1 25iX SUV, X1 28i SUV, X1 28iX SUV, X2 20i SAC, X2 20iX SAC, X2 25i SAC, X2 25iX SAC, X2 28i SAC, X2 28iX SAC, X2 M35iX SAC, X3 20i (TR12) SUV, X3 20i (TR16) SUV, X3 20i 1.6 SUV, X3 20i SUV, X3 20iX (TR51) SUV, X3 20iX (TR52) SUV, X3 20iX (TR55) SUV, X3 20iX (TR56) SUV, X3 20iX SUV, X3 25iX SUV, X3 28iX SUV, X3 30eX SUV, X3 30i SUV, X3 30iX (TR91) SUV, X3 30iX (TR92) SUV, X3 30iX (TR95) SUV, X3 30iX (TR96) SUV, X3 30iX SUV, X4 20iX SAC, X4 30iX SAC, X5 30iX SUV, X6 30iX SAC, Z4 20i Roadster, Z4 30i Roadster,

2019

120i 3 doors, 120i 5 doors, 120i Sedan, 125i 3 doors, 125i 5 doors, 220i Active Tourer, 220i Convertible, 220i Coupe, 220i Gran Tourer, 225i Active Tourer, 225iX Active Tourer, 228iX Gran Coupe, 230i Convertible, 230i Coupe, 230iX Convertible, 230iX Coupe, 320Li Sedan, 320LiX Sedan, 320i 1.6 Sedan, 320i Gran Turismo, 320i Sedan, 320i Touring, 320iX Gran Turismo, 320iX Sedan, 320iX Touring, 325Li Sedan, 325LiX Sedan, 325i Sedan, 330LiX Sedan, 330e Sedan, 330i Gran Turismo, 330i Sedan, 330i Touring, 330iX Gran Turismo, 330iX Sedan, 330iX Touring, 420i Convertible, 420i Coupe, 420i Gran Coupe, 420iX Coupe, 420iX Gran Coupe, 430i Convertible, 430i Coupe, 430i Gran Coupe, 430iX Convertible, 430iX Coupe, 430iX Gran Coupe, 520i 1.6 Sedan, 520i Sedan, 520i Touring, 525Li Sedan, 530Le Sedan, 530Li Sedan, 530LiX Sedan, 530e Sedan, 530eX Sedan, 530i Sedan, 530i Touring, 530iX Sedan, 530iX Touring, 630i Gran Turismo, 730Li Sedan, 730i Sedan, 740Le Sedan, 740LeX Sedan, 740e Sedan, 740eX Sedan, Cooper S ALL4 Clubman, Cooper S ALL4 Countryman, Cooper S 3 doors, Cooper S 5 doors, Cooper S Clubman, Cooper S Convertible, Cooper S Countryman, JCW ALL4 Clubman, JCW ALL4 Countryman, JCW 3 doors, JCW Convertible, M135iX 5 doors, M235iX Gran Coupe, X1 20Li SUV, X1 20LiX SUV, X1 20i SUV, X1 20iX SUV, X1 25Li SUV, X1 25LiX SUV, X1 25iX SUV, X1 28i SUV, X1 28iX SUV, X2 20i SAC, X2 20iX SAC, X2 25i SAC, X2 25iX SAC, X2 28i SAC, X2 28iX SAC, X2 M35iX SAC, X3 20i (TR12) SUV, X3 20i (TR16) SUV, X3 20i 1.6 SUV, X3 20i SUV, X3 20iX (TR51) SUV, X3 20iX (TR52) SUV, X3 20iX (TR55) SUV, X3 20iX (TR56) SUV, X3 20iX SUV, X3 25iX SUV, X3 28iX SUV, X3 30eX SUV, X3 30i SUV, X3 30iX (TR91) SUV, X3 30iX (TR92) SUV, X3 30iX (TR95) SUV, X3 30iX (TR96) SUV, X3 30iX SUV, X4 20iX SAC, X4 30iX SAC, X5 30iX SUV, X6 30iX SAC, Z4 20i Roadster, Z4 30i Roadster,

2020

320i Sedan, 330e Sedan, 520i Sedan, 630i Gran Turismo, 730Li Sedan, 730i Sedan, X1 20i SUV, X1 20iX SUV,

Intermediate level repair.

Step 1 - Purchase Parts

You will need the following parts and supplies to perform this repair.

Auxiliary Coolant Pump

The turbochargers in your BMW get hot...we mean seriously hot. These brutal conditions take their toll on the turbochargers internal parts, especially the bearing seats. Without proper cooling, the turbochargers lifecycle is seriously shortened meaning an expensive trip to the repair shop. This Genuine BMW auxiliary turbocharger cooling pump is the same factory pump installed at the dealership. Don't be fooled by cheap aftermarket pumps sold on Amazon and Ebay...they do not last and can end up damaging your engine.

Step 2 - Repair Procedure

Unless otherwise noted, all vehicle repair step images in this article are copyrighted, and used courtesy of BMW of North America, Inc. .

The high temperature coolant system must be drained before starting this repair.

For detailed instructions on how to drain and refill the high temperature coolant system, please see our article Coolant Flush and Replacement - BMW B46/B48 Turbo 4 Cylinder Engine.

1. Replacing the turbocharger auxiliary coolant pump

Remove the acoustic cover from the engine

Click to enlarge image

- Remove the acoustic engine cover by pulling it up until it releases from its rubber grommets.

View part diagram for this step

Click to enlarge image

- Remove the radiator cover (1) by pulling it up until it releases from its rubber grommets.

View part diagram for this step

Click to enlarge image

- Disconnect the hot-film air mass meter (1) from the intake muffler (4).

- Loosen the hose clamp (2) connecting the intake silencer to the clean air pipe (3)

- Grasp the intake muffler and pull it loose from its rubber grommets and remove from vehicle.

View part diagram for this step

Click to enlarge image

- Next, remove the clean air pipe (4) by first disconnecting the vent pipes (1) and (2).

- Unlock the spring clip (3) and pull the clean air pipe free from the turbocharger.

View part diagram for this step

Click to enlarge image

- Unplug the charge air pressure sensor (1) and the temperature sensor (3).

- Remove the three torx screws anchoring the charge air line to the throttle body.

- Release the locking clamp (4) and pull the charge air line free from the turbocharger.

- Remove the charge air line from the engine compartment.

View part diagram for this step

cut the front acoustical panel where it is perforated

Click to enlarge image

- Locate the front acoustical cover mounted to the lower front of the engine.

- Using a razor knife, cut the small tabs shown in the image.

View part diagram for this step

remove the plastic rivets anchoring the front acoustical cover

Click to enlarge image

- Remove the plastic rivets anchoring the acoustic cover to the engine. Remove the cover from the engine compartment.

View part diagram for this step

disconnect the coolant lines from the auxiliary coolant pump and unplug

Click to enlarge image

- Locate the auxiliary coolant pump on the front of the engine.

- Disconnect the coolant hoses and unplug the electrical connector (2).

View part diagram for this step

remove the two torx bolts anchoring the auxiliary coolant pump to engine

Click to enlarge image

- Remove the two torx bolts (1) anchoring the auxiliary coolant pump to the engine block. Remove the coolant pump from the engine.

View part diagram for this step

2. Final installation notes and torque values

- Torque coolant pump to engine block mounting bolts to 8 Nm (6 ft-lb).

- Make sure when reinstalling the coolant lines you hear them firmly snap into place.

- Follow the instructions in our article Coolant Flush and Replacement - BMW B46/B48 Turbo 4 Cylinder Engine on refilling and bleeding the coolant system.