E30 318i M40: GUIDE - Replacing lower inlet-manifold gasket - rough idle and stalling fixed!

After all the diagnosis and testing from THIS POST, I found the cause of my rough idle and stalling out when cold was a damaged paper gasket on the lower inlet-manifold allowing unmetered air to be drawn in to the plenum at will and confusing the AFM and DME over how much fuel to deliver. 

The engine just about ticked over when warm, albeit with a slight misfire. On cold startups however, the misfire was a lot more severe and at low revs the engine just couldn’t hold on, stalling out due to a way over-lean mixture. It would drive though, but there was no throttle response until about halfway up the rev range and power would arrive with a bang. It is amazing how sensitive these older engines with analog electronics are to unmetered air leaks!

IF YOU HAVE THESE SYMPTOMS, CHECK HERE!

I ordered a new gasket from eBay, it was a snip at £6.88. Be careful when ordering, older M10 engine gaskets are far more plentiful, so ensure yours is the right one for the M40... they have a funny shape which is quite distinctive. Choice was limited, in fact I could find one more gasket for sale of the right type and that came with a full £30 set including a head gasket, so be sure to check out carpartsinmotion, they have rare-fit stuff.

GUIDE:

1. Undo the jubilee-clip and disconnect the large rubber duct from the throttle-body using a flat screwdriver or 7mm socket.

2. Unclip the throttle-cable from the throttle-linkage and remove the two 10mm screws holding the metal plate to the throttle-body so the cable assembly can be moved clear.

3. Remove the wiring connectors from the throttle position sensor [TPS] and idle control valve [ICV].

4. Remove the rubber hose from the bottom of the ICV.

5. Remove the vacuum air hose from the front side of the throttle-body by undoing the jubilee-clip and teasing it off carefully with a flat screwdriver.

6. Remove the two coolant hoses from either side of the throttle-body by undoing the jubilee clips and teasing them off with a flat screwdriver. 

7. Remove the six nuts from the upper inlet-manifold using an 11mm wrench [9 in diagram] and two locating studs in the centre with a 10mm wrench [13 in diagram]. 

8. The upper inlet-manifold can now be lifted out of the engine bay.

9. Remove the wiring connector from the fuel-rail / injectors. 

10. Remove the metal fuel send and return pipes from each end of the fuel-rail by undoing the jubilee clips. (This is where it gets messy, you may wish to plug or clamp the ends of these hoses). The send pipe is attached to the fuel pressure regulator [FPR] at the front of the fuel-rail and the return pipe is at the back of the rail.

11. Remove the five nuts holding the ports of the lower inlet-manifold to the head using an 11mm socket [4 in diagram].

12. Remove the two bracing bolts from the lower inlet-manifold using a 13mm socket. (They point towards the right side of the car) [11 in diagram].

13. The lower inlet manifold is now free to be removed. This can be a bit tricky as the rigid fuel pipes are routed through one of the gaps in the manifold ports. Also make a note of how the hoses to the throttle-body are routed through around the lower manifold, as it can be confusing once the upper manifold is bolted back in.

14. Clean off the mating surfaces of the cylinder head and the inlet manifold.

15. Carefully fit the new gasket to the studs on the head. It only fits one way round.

16. To refit reverse the above steps.

E60: Replacing Rear Rose-Bushes / Lower Ball-Joints

These are the main joint where the rear wheel-hubs attach to the trailing-arms and are a pretty common replacement on high mileage 5 and 7 series. They were the advisories I got on the MOT in February, so thought I should get them done before the nice weather ends.

DIFFICULTY - 6/10 This is not a long or complicated job, but is quite labour intensive.

** YOU WILL NEED: A dedicated removal / installation tool. These are available on eBay [here] for just under £40 and work for all modern 5, 6, 7, X5 and X6 rose-bushes. These are all copies of the BMW special tools listed here on TIS.

The rose-bush is item 2 in the diagram.

1. Lift car, remove rear wheel, support on axle-stand.

2. Unbolt the anti-roll bar link from the trailing-arm using an 18mm open/ring spanner on the nut from underneath, while holding the stud from turning using a T40 Torx socket through the centre of the spanner.

3. Loosen the long bolt that holds the trailing-arm to the wheel hub [5] using a 24mm wrench on the nut and an 18mm wrench on the bolt head. [A long breaker-bar is advisable on the nut.]

4. Loosen off the eccentric-bolt on the trailing-arm [11] using an 18mm wrench on the bolt head and a 21mm wrench on the nut. [Be careful not to turn the bolt and alter the alignment as it's hard to get back.]

5. Loosen off the other bolt on the trailing arm [9] using an 18mm wrench on both the nut and bolt head.

6. Fully remove the 24mm nut [6] and long bolt [5] from the wheel-hub. [The bolt will likely need knocking out with a drift.]

7. Remove the bolt holding the push-rod to the wheel-hub [7] using an 18mm wrench.

7a. (O/S trailing-arm only) - Disconnect the suspension-angle sensor from the trailing-arm using a 10mm wrench and 10mm open-end spanner.

8. Lever the trailing arm down so it is clear of the wheel-hub and the push-rod [4] can be removed.

9. Remove the retaining-ring [3] from the rear face of the rose-bush. [It will likely be well seized in place and need splitting with a grinder / cut-off tool before knocking out in two pieces.]

10. Set up the removal-tool either side of the rose-bush with the largest mandrel on the receiving side and the smallest mandrel on the pushing side, ensuring the pushing side is completely flush to the rose-bush face. [Some of the rose-bush rubber boot may need cutting off to ensure this.]

11. Tighten up the removal-tool using a 19mm wrench on either side until the bush pops out of the wheel-hub. [Rotating the receiving mandrel round so the notched area can be viewed from underneath shows the progress of the bush coming out.] [The bush may well need some heat treatment if it is seized, or you can have a go at splitting it if you are brave enough.]

12. Place the new rose-bush into the hub, ensuring it is straight to the collar and will go in evenly. [The bush always slots it from front to rear, with the retaining ring on the rear face.]

13. Set up the removal-tool on the new rose-bush with the largest mandrel on the receiving side again and the mid-sized mandrel on the pushing side. [The notched side of the receiving mandrel will need rotating so it fits flush past the back of the brake disc. This is essential to keep the threaded-bar / bush straight.]

14. Tighten up the removal-tool with two 19mm wrenches until the bush is fully seated in the collar. [The bush should slide in pretty easily, if it resists then it is not going in straight. A small amount of copper grease can be rubbed round the bush to aid it, but be very sparing.]

15. Fit the new retaining-ring to the rear face of the rose-bush.

16. Refit the push-rod and trailing arm etc. as a reversal of steps 8 to 1.

** For correct re-alignment of suspension geometry see this post. **

E60: Cracked lower timing-case - engine finished.

Yeah well that's torn it. Literally, torn it open. After all that effing about with the sump removal, finding the right piston and drilling off those snapped head bolts, I find a whopping great crack in the lower timing-case!

I wonder what caused this? Vibration from the swirl-flap doing its dance? High crankcase pressure from the dodgy piston? Who knows, but we can safely say that's where the oil leak was coming from!

It's a big enough job as it is to replace that single damaged piston, but to swap the lower timing-case as well involves stripping the entire front of the car, getting all the pulleys off and fully removing the crankshaft. Hmm, a lot of work and a lot more cost, this definitely calls for a replacement engine... Watch this space!!