B58 Expansion Tank and Vent Hose Replacement

Fits US B58 cars (G20 M340i first)

G20 M340i (B58TU), G05 X5 40i, F30 340i, F22/F23 M240i, F32/F33/F36 440i, G30 540i, G01/G02 X3/X4 M40i. HT tank catalog position varies by VIN.

You replace the HT coolant expansion tank and vent hose. G20 M340i and G05 X5 40i reach the HT tank through the front wheel well; Gen 1 cars use paired LT and HT tanks in the bay; G01/G02 M40i use the fender well after underbody trim.

Wheel bolt M14: 140 Nm
Wheel arch liner: 2.6 Nm
Tension strut screw: 56 Nm + 90 deg

Before you start

Work on cooled parts only. Disconnect the battery negative on wheel-well cars. Do not drive without the tension strut, front strut, or front stiffening plate reinstalled.

Out in this order (G20 M340i / G05 wheel well)

Battery negativewheel-well path only
Tension strutnew M10 screw
Front wheelworking side
Wheel arch linerfront section
Drain and disconnectlines, level plug
HT expansion tankvent hose while out

What you replace

HT expansion tank

G20 M340i (B58TU): 17 13 8 610 652 BMW B58 Coolant Expansion Tank Kit G20/G29 (Rein tank, cap, vent screw, lid) or 17 13 8 610 653. Send us your VIN and we'll send yours.

G05 X5 40i: 17 13 8 610 662 or 17 13 8 610 661.

Gen 1 F-chassis: 17 13 8 677 649 or 17 13 8 617 045. Genuine BMW tank · Rein tank · Febi tank

G01/G02 M40i: 17 13 8 742 660 Rein EPT0262 Coolant Expansion Tank G01/G02 or 17 13 8 610 661.

G30 540i: 17 13 9 485 733 Febi 174442 Coolant Expansion Tank G30 or early 17 13 9 884 859.

Sealing cap, vent screw, grommet, cover lid

G20: cap 17 13 8 665 638, vent screw 11 53 7 793 373 with O-ring 11 53 7 793 248, grommet 17 13 8 642 788, lid 17 11 7 639 024.

Gen 1: cap 17 11 7 639 020 Genuine BMW cap, same vent screw and O-ring as G20, lid 17 11 7 639 024, bracket 17 13 8 634 324.

G01/G02: grommet 13 71 8 643 158.

Expansion tank vent hose or line

G20 M340i: hose 17 12 8 654 832.

F30 340i: hose 17 12 8 616 558, line 17 12 8 616 531.

F22/F32/F36 and other Gen 1: Send us your VIN and we'll send yours.

G01/G02: 17 12 7 535 567 or supersession 17 12 9 894 754.

G05 X5 40i: 17 12 8 654 310.

Coolant after a tank swap

Tank swap means drain and refill the cooling system. Send us your VIN and we'll send the correct antifreeze and fill volumes.

Renew on reinstall

Wheel-well: new tension strut M10 screw. G30 bay: new strut tower screws.

Steps, torque values and part rules come from BMW's repair instructions for coolant expansion tank and vent hose replacement. Part numbers come from BMW's parts catalog up to 2020. Check yours by VIN.

Drawing of the HT expansion tank installed in the wheel well with numbered dots: 1 HT expansion tank; 2 Tank lock; 3 Coolant hose stubs — HT expansion tank

Tank lock

Coolant hose stubs

Generic layout: yours may differ.

Tools

Socket set and trim tools

Strut, wheel arch, underbody, and engine cover hardware.

Coolant disconnect tools and drain pan

Unlock quick connectors cleanly.

Hand ratchet for strut tower work

Do not use an impact driver on strut tower threads.

Calibrated torque wrench

Wheel and strut fasteners; no impact guns.

Battery wrench and PPE

Negative terminal and hot coolant.

Steps

Disconnect battery negative

Disconnect the negative battery terminal before you open the wheel well on G20 M340i and G05 X5 40i; skip this on engine-bay-only paths.

Caution: do not pry the clamp off; no charger on the jump-start point while the terminal is off.
Remove tension strut

Remove the tension strut at the strut tower on wheel-well cars.

Caution: do not drive with the tension strut removed. Plan to install a new M10x55 screw at 56 Nm plus 90 degrees and tighten the rear M8x30 screw to 28 Nm on reinstall.
Remove front wheel

Remove the front wheel on the side you are working.

Caution: remount wheel bolts to 140 Nm with a calibrated wrench only; clean and degrease the hub face before the wheel goes on.
Open wheel arch liner
1. New M10 strut tower screw
2. M8 cross member screw
3. Tension strut
Generic layout: yours may differ.
Remove the front section of the wheel arch liner to expose the HT tank in the front wheel well.
Drain and disconnect tank
1. Open filler neck
2. Coolant line quick connectors
Generic layout: yours may differ.
Release the cap, draw off coolant, unlock and disconnect coolant lines and the level plug, then unlock the tank lock and remove the HT expansion tank.

Caution: hot coolant needs PPE; do not reuse drained coolant.
Replace vent hose

Swap the vent hose or line for your chassis while the tank is out; lock the fitting until it clicks.

Caution: Gen 1 vent OE outside the F30 catalog row: send us your VIN and we'll send yours.
Install new HT tank
1. HT expansion tank
2. Tank lock
3. Coolant hose stubs
Generic layout: yours may differ.
Install the new HT tank, engage the lock, connect lines and plug until each lock clicks, fill to MAX, and align the cap arrows.

Caution: every coolant lock must engage audibly on reconnect.
Reinstall wheel arch

Reinstall the wheel arch section and torque thermoplastic screws and nuts to 2.6 Nm.
Reinstall wheel and strut

Remount the wheel at 140 Nm (torque the brake disc M8 hub bolt to 16 Nm first if you disturbed it), fit a new tension strut M10x55 screw at 56 Nm plus 90 degrees, and tighten the M8x30 screw to 28 Nm.
Refill cooling system

Top up after a full drain and refill the cooling system to MAX. Send us your VIN and we'll send antifreeze type and fill volumes for your car.
Gen 1: open engine bay

Remove the front strut and unclip the design cover on F30 340i, F22/F23 M240i, and F32/F33/F36 440i before you reach both tanks.

Caution: remove or install the design cover only above 20 degrees C; use distilled water on clips at install, not lubricants.
Gen 1: remove HT tank

Drain both tanks, unthread the LT tank from the HT tank if needed, and lift out the HT expansion tank.

Caution: refill both tanks to MAX when you reinstall.
Gen 1: reinstall tanks

Reinstall tanks, fill both to MAX, close both caps, tighten the front strut to 28 Nm, and clip the design cover.
G01/G02: fender well path

Remove the front underbody and lower wheel arch cover, drain and disconnect the LT tank, then remove the HT tank from the fender well.

Caution: only flexible hose pipes may be disconnected on G01/G02; torque arch and underbody fasteners to 3 Nm.
G30 540i: bay access

Reach the HT tank from the engine bay after the bonnet seal, center engine cover, and front strut come off. Some G30 builds also use an underbody trim path; send us your VIN and we'll confirm yours.

Caution: renew front-end strut tower screws on reinstall; tighten the strut brace screw to 56 Nm plus 90 degrees and the cross connection bolt to 28 Nm plus 90 degrees where those fasteners are used.