B58 Turbo Oil and Coolant Line Replacement

Fits US B58 cars (G20 M340i first)

Same US B58 list as the intro. Line part numbers split Gen 1 B58 versus B58C/B58D/TU in the parts list below.

You are replacing the turbo oil feed line, oil return line, and the turbo coolant feed and return lines with the turbo still in the car on a G20 M340i xDrive. Wet fittings at the turbine housing mean new lines, new seals, and clean connections. Gen 1 F-chassis cars and G20 rear-wheel-drive oil return work use different access paths labeled in the steps.

Line bolts: 8 Nm
Oil feed O-rings: Renew both
Stiffening plate: 56 Nm

Before you start

Catch oil and coolant and work on a cooled engine. Cover every open port, use seal plugs, and keep dirt off line connections. Do not drive without the front stiffening plate reinstalled. If the turbo moves, do not pull the wastegate controller or coupling rod.

Out in this order

Bonnet service positionG20 M340i xDrive
Acoustic coverabove 20 degrees C
Strut bars and cowlfan cowl, intake silencer
Charge air lineclear the turbo
Turbo linescoolant feed and return, oil feed

What you replace

Oil feed line

G20 M340i, G01/G02 M40i (B58D/TU), G05 X5 40i and G30 540i (B58C): 11 42 8 679 019

Gen 1 F30 340i, F22/F23 M240i, F32/F33/F36 440i, early G30/G01: 11 42 7 643 175

BMW B58 Gen 1 Turbo Line Kit (5 Rein oil and coolant lines)

Oil return line

B58D/TU and B58C on the cars above: 11 42 8 679 020

Gen 1 US B58: 11 42 7 643 176

Coolant feed line at turbo

B58D/TU and B58C: 11 53 8 650 086 (flow to turbocharger)

BMW B58TU Turbo Coolant Line Pair (Genuine supply and return)

Gen 1 US B58: 11 53 7 643 177 (crankcase to turbo)

Coolant return line(s) at turbo

B58D/TU and B58C: 11 53 8 650 087 (return from turbocharger)

Gen 1 US B58: 11 53 8 666 856 and 11 53 8 666 857 (the two turbo-to-coolant-pump lines; crankcase-to-turbo feed is 11 53 7 643 177 above)

Oil feed line O-rings

11 42 7 590 576 (11x1.78) and 11 42 7 590 577 (15x1.78). Renew both on install.

Coolant line O-ring at turbo fittings

12x1.5 size. 11 53 7 590 575 on most US B58 cars (qty 3 Gen 1, qty 2 B58C, qty 1 B58D/TU including G20 M340i). Gen 1 N cars (F22N/F23N, F32N/F33N/F36N, F34N): 11 27 7 702 625 (qty 3). Send us your VIN if your build is not listed.

Line fasteners

M6 x 12 screw 07 12 9 905 867 at turbo oil line joints.

Gen 1 coolant return path extras

Renew intake plenum seals when the plenum comes off. Renew stiffening plate screws on Gen 1 F23/F33 rear-wheel-drive reinstall per the oil feed procedure.

Steps, torque values and part rules come from BMW's repair instructions for B58 turbo oil and coolant line replacement with the turbo in place. Part numbers come from BMW's parts catalog up to 2020. Check yours by VIN.

Drawing of the oil return line at turbo and crankcase with numbered dots: 1 Oil return line; 2 Oil return at turbo; 3 Oil return at crankcase — Oil return line

Oil return at turbo

Oil return at crankcase

Generic layout: yours may differ.

Tools

Socket set and trim tools

Underbody panels, acoustic cover clips, and charge air clamps.

Drain pans, rags, and seal plugs

For open turbo line ports.

O-ring pick and seal wedge

For coolant and oil line O-rings without scratching ports.

Coolant return line release tools

For the turbo coolant return joint on G20 M340i xDrive.

Bonnet service props

Hold the bonnet in service position on xDrive cars.

Coolant fill and bleed gear

Refill the high-temperature circuit after any coolant line opens.

Steps

Catch fluids first

Drain or catch oil and coolant and let the engine cool before you open any turbo line.
Bonnet service position
1. Bonnet service prop
2. Gas strut
3. Hood ball pin
Generic layout: yours may differ.
Set the bonnet service position on G20 M340i xDrive before you remove strut hardware.
Remove acoustic cover

Remove the engine acoustic cover only when ambient temperature is greater than 20 degrees C.

Caution: wait out an electric fan run of up to 11 minutes after a hot shutdown before fan cowl work.
Struts and fan cowl

Remove the front strut bars, cross connections, fan cowl, intake silencer, and charge air line to clear the turbo.

Caution: do not lift the turbo by the compressor tray if you move it later on a Gen 1 job.
Remove lines at turbo
1. M6 x 12 line screw at turbo
2. Wrench on line screw
3. Turbo hard line fitting
Generic layout: yours may differ.
Remove the coolant feed, coolant return, and oil feed lines at the turbine housing on G20 M340i xDrive once the cowl and charge air are off.

Caution: if the coolant return inner O-ring is damaged, replace the complete return line, not the ring alone. On oil return replacement, clean the coked connection pipe on the oil pan.
Install lines and seals

Renew seals and O-rings, install the lines, and torque each M6 x 12 line fastener to 8 Nm.
- Oil feed: new 11 42 7 590 576 (11x1.78) and 11 42 7 590 577 (15x1.78) O-rings.
- Coolant fittings at turbo: new 12x1.5 O-rings (see parts list for your engine).
Caution: coolant hose quick connector locks must click audibly on reconnect.
G20 RWD oil return
1. Oil return line
2. Oil return at turbo
3. Oil return at crankcase
Generic layout: yours may differ.
On G20 M340i rear-wheel-drive, remove front underbody protection, the stiffening plate, and the steering assembly cover, then replace the oil return line from underneath. Renew oil return sealing rings on install. Torque oil return M6 x 12 at turbo and crankcase to 8 Nm, steering assembly cover screws to 3 Nm, thermoplastic underbody bolts to 2.6 Nm, M6 x 20 underbody bolts to 8 Nm, and the stiffening plate to 56 Nm.
Gen 1 oil return only

On Gen 1 F-chassis cars when only the oil return line is due, remove underbody panels, renew seals, torque M6 x 12 line fasteners to 8 Nm, and reinstall underbody protection.
Gen 1 coolant returns
1. Intake plenum opening
2. Auxiliary turbo coolant pump
3. Pump electrical connector
4. Coolant hose at pump
Generic layout: yours may differ.
On Gen 1 F30 B58 cars, remove the intake plenum and auxiliary turbo coolant pump at the back of the engine, replace the two Gen 1 coolant return lines, renew plenum seals, torque intake plenum screws in sequence 1 to 7 at 5 Nm then 10 Nm, and torque each M6 x 12 coolant line screw to 8 Nm.

Caution: keep coolant out of the cylinder head intake ports while the plenum is off.
Gen 1 oil feed path

On Gen 1 cars when the oil feed line or full line set is due, follow the deeper prep: acoustic cover, intake, charge air, O2 sensors, underbody, exhaust and catalyst out, and high-temperature coolant drain as required.
- Gen 1 F23/F33 rear-wheel-drive stiffening plate: M10 x 22 to front axle support at 56 Nm plus 45 degrees; M10 x 16 to adapter plate at 56 Nm plus 90 degrees with new stiffening plate screws.
Caution: do not drive without the stiffening plate. Do not pull the wastegate controller if the turbo moves during this path.
Refill and check levels

Refill high-temperature coolant and check engine oil level if you drained or lost fluid.
Reinstall trim and covers

Reinstall charge air, intake, strut bars, fan cowl, and acoustic cover on G20 xDrive, or the trim you removed on Gen 1 and G20 rear-wheel-drive paths.

Caution: install the acoustic cover only above 20 degrees C ambient.