Cylinder Head Remove and Install

REMOVING CYLINDER HEAD
- Take off intake manifold support and venting hose from valve cover.




- Unscrew nut (1...8) and take off valve cover.

Installation Note:
- Check gasket, replacing if necessary.
- Tighten nuts in order of 1 through 8.
- Tightening torque = 9 Nm (6.5 ft. lbs).

- Disconnect battery.

CAUTION: Disconnecting the battery will cancel (clear) the memory of control units which have diagnostic trouble code capabilities. Be sure to interrogate all control units for possible diagnostic trouble codes prior to disconnecting the battery.
BMW anti-theft radios can be rendered useless by disconnecting the battery. Make sure you know the correct code before disconnecting the battery. See your owner's manual for more information.




- Unscrew exhaust pipes on exhaust manifolds and loosen clamp of holder on transmission.

Installation Note: Replace gaskets and self-locking nuts. Coat studs with copper paste. Tightening torque = 50 Nm (36 ft. lbs.).




- Drain coolant on engine and radiator.
- Drain engine oil.

Installation Note: Fill and bleed cooling system.




- Disconnect cables and unscrew holder.




- Loosen hose clamp and pull off intake air hose on air cleaner.
- Pull off plug on air flow sensor.




- Pull off plug on idle speed control.
- Cut off wire strap and pull off vacuum hose for brake booster.




- Disconnect radiator hoses (1 and 2), heater hose (3) and fuel hoses (4 and 5).

Installation Note: Don't mix up fuel hoses (4 and 5).




- Pull off hose (1) and plugs (2 and 3).
- Disconnect plug (4).




- Unscrew knurled nut and take off plug.
- Unscrew nut and take wire connector plate off of intake manifold.




- Remove fan.
- Lift out expansion rivets at left and right top on fan cowl and remove fan cowl.

Installation Note: Check for correct seating of bottom guide.




- Loosen clamp and take off preheating hose.
- Unscrew guide tube for oil dipstick on manifold.
- Remove toothed drive belt, refer to Timing Belt, Service and Repair.




- Disconnect heating hose on cylinder head.




- Press down on venting pipe and arrest with Special Tool 11 1 290.

Installation Note: Check seal, replacing if necessary.
Check for correct seation of venting pipe after removal of Special Tool 11 1 290.

6 Cylinder M20 Tighten Sequence:

- Release cylinder head bolts working from outside to inside in sequence 14...1.
- Remove cylinder head.




INSTALLING CYLINDER HEAD:

NOTE:
An improved cylinder head bolt has been introduced for use in the M20 engine. The new head bolt, designated ASA 14, is grade 10.9 and is identified by the Torx head and a black surface finish. Whenever engine repairs necessitate cylinder head removal, all 14 old style head bolts should be replaced with the ASA 14 bolts. Further, in instances of head bolt damage (e.g. head broken off), all 14 head bolts should be replaced one by one without removing the cylinder head. The waiting and running time requirements are no longer used.

The new ASA 14 head bolt has revised expansion properties which require new torque angle values.
Step 1 - Torque all bolts to 30 Nm (22 ft.lbs.).
Step 2 - Torque angle all bolts 90°.
Step 3 - Torque angle all bolts 90°.

CAUTION: Under no circumstances should the old and new head bolts be mixed in one engine. Remove oil and debris from bolt holes. If not, improper values or damage may result.

- Clean sealing surfaces.
- Fit cylinder head gasket in position, Cylinder Head Gasket, Replace.
- Install new, lightly oiled bolts. Use special tool 11 2 110 or 00 9 120 in the torqueing sequence 1...14.
- Reinstall all auxiliary components in reverse order of disassembly, paying close attention to installation notes and torque specs.
- Adjust valve clearance, refer toValve Clearance.
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- Check engine idle speed and CO level.