Rounded Bolt - Replacing Cam Position sensor on 3.0

[nblu]

Hi everyone,
This is my first post on the forum, so apologies for asking for advice as my first post. I've got a 2009 E89 sDrive 3.0, which has 2AA0 and 2AA1 fault codes on the intake and exhaust position sensors.

The excellent advice on the forum helped me track down the solution, and I've managed to replace the exhaust side, but I can't remove the screw on the intake side. Does anyone have any suggestions?

I've tried penetrating oil, fluted bolt removers and hammering a socket on. But, with the position and limited, I've had trouble getting enough force to get anything to hold on. I'm at the point I'm tempted to give up and get someone to do it, but I thought I would ask on here first.

Thanks,
Nick

 

[smorris_12]

Odd. Not a high torque bolt so can't imagine it would be hard to shift. Was it that the corners had been taken off the bold head and a 12pt socket wouldn't grip it (usual solution find a proper 6-sided hex socket but probably too late for that.)

If you don't mind destroying the sensor the breaking the mounting tag out from underneath the bolthead should either release tension or give you something to grab with mole grips etc.

At worst to be able to get serious tools at it, and I'm basing this on where they are on my E85 in relation to the body, either loosening the engine mounts and jacking the engine up or removing the radiators (air-con one is a pain to deal with of course.)

 

[nblu]

Thanks for the advice. I’ve got the sensor off and I’ll see if I can get some mole grips on to get the rest off. I already had the replacement but I didn’t want to mess this up any more. I confess it was my fault as I didn’t have my E6 on straight.

I’ve added a photo of my progress.

Thanks,
Nick

 

[smorris_12]

Ah, I was confusing the solenoids with the sensors (they're M6 hex head bolts.) Not played with those yet so not quite sure where they are in relation to everything. Looks like the metal collar from the sensor is still under the bolt head. That might be keeping the bolt in tension.

Otherwise, if there's nothing plastic too close, then a bit of heat from a blowtorch works wonders with things.

 

[nblu]

I've added more penetrating oil to soak in; I'll try applying heat afterwards.

The photo shows the inlet side of the N52 from the front. The Vanos solenoids are on the left with rusty bolts.

This should have been a 10-minute job. On the bright side, I've had the car since new, and this is the first time I've got my hands dirty. So it has been a great learning experience...

Thanks,
Nick

 

[flybobbie]

How's it got so corroded, been in a flood?
My N52 engine like new, 14 years old next month.

 

[nblu]

How's it got so corroded, been in a flood?
My N52 engine like new, 14 years old next month.

I confess I fell out of love with it when I had a roof fault and was fed up with dealerships replacing the roof wiring and microswitches (twice so far). I also had the dreaded leaking of the rear lights which damaged the roof.

I suspect the corrosion is due to not using and leaving it on the driveway 3 miles from the coast. I have had it under a cover for the last 12 months, and it was barely used in the previous five years. It has done 63k miles, and 40k of those were in the first four years. These engines really need to be used to keep them at their best.

I had been considering selling it, but I would love to get it running smoothly again. The cam sensor is the only issue stopping me from using it, as it is causing an engine warning light which I understand is an MOT failure these days. Once I have that sensor out it is getting a full service and possibly a few upgrades (I'm tempted by the hifimax display as I don't have iDrive).

I've attached a photo of it from many moons ago. I know the turbine alloys are an unusual choice and it used to be in your neck of the woods so you might have seen it.

Thanks,
Nick

 

[javis20]

While your there, you might want to pull the two vanos solenoids. Clean them up and reoil and cycle with 12 volts.

https://www.youtube.com/watch?v=K0594cw9KbE

 

[nblu]

While your there, you might want to pull the two vanos solenoids. Clean them up and reoil and cycle with 12 volts.

https://www.youtube.com/watch?v=K0594cw9KbE

Thanks, that’s on my list, I’ll replace the bolts at the same time. Sensors are the priority followed by the vanos, replacing the spark plugs and oil change. I had been considering doing an engine flush but I’ve seen mixed opinions on the success.

 

[flybobbie]

Perhaps a Dremel tool to cut away the metal insert to relieve pressure on screw.
Would also give slightly better grip.
Also on cold engine try kettle of boiling water to expand the aluminium around the screw.
Keep mole grip on screw to act as a heat sink.

 

[nblu]

Thanks for the advice.

I've been away but am back to looking at the bolt again. I've been trying a bolt/stud extractor on it and ended up with this mess. I suspect the iron oxide corrosion has come from the metal sensor collar, as I can't explain where else it could have come from.



I will try the kettle or blowtorch next; I'll keep the post updated in case anyone else has the same issue.

Thanks,
Nick

 

[smorris_12]

I'd say go straight for the blow torch. If that's not moving and it's looking like that there's got to be some deep seated corrosion there.

 

[mcbutler]

Thanks for the advice.

I've been away but am back to looking at the bolt again. I've been trying a bolt/stud extractor on it and ended up with this mess. I suspect the iron oxide corrosion has come from the metal sensor collar, as I can't explain where else it could have come from.

IMG_2788.jpeg

I will try the kettle or blowtorch next; I'll keep the post updated in case anyone else has the same issue.

Thanks,
Nick

Yep thats a plan, heat it to cherry red if you can, let it cool and repeat a few times, but look out for any alloy compnents. Aluminium shows no sign of its heating and will just collapse and melt without warning

 

[srhutch]

These might help

https://www.machinemart.co.uk/p/5-piece-bolt-grip-set-expansion-set/

 

[nblu]

These might help

https://www.machinemart.co.uk/p/5-piece-bolt-grip-set-expansion-set/

I’ve tried a set from AB Tools but they didn’t bite into the bolt. It is hard to hammer anything on in the space. I confess they were cheap and probably that was part of the problem.
6pc 3/8" Drive Or Drill Bolt Extractor Wheel Lock Nut Remover Set 6mm - 12.7mm https://amzn.eu/d/9MRk7DN

Would the Irwin be much better?

Thanks,
Nick

 

[smorris_12]

I've got a set of those and they struggle at the best of times. At the front of the engine, no chance.

I take it you've tried mole grips on it?

 

[nblu]

Thanks everyone. I have finally managed it after getting a decent quality set of pliers. Everything else I tired wouldn’t bite. I should have invested in them sooner.


Lesson learned.

Thanks,
Nick

 

[smorris_12]

That's a lifetime pair. Knipex make some serious gear.

Glad it's sorted!

 

[nblu]

That's a lifetime pair. Knipex make some serious gear.

Glad it's sorted!

Thanks, I thought it was the last thing to try before giving in and letting a professional look at it. For £27 it was much better than the cheap Draper set I had tried.

In case it is useful to others the new parts cleared my fault codes. I was getting 2aa0 intake cam position, 2aa1 exhaust cam position and 29ce misfire cylinder 2. The first two codes were fixed by the cam position sensors. The 29ce was fixed by replacing the ignition coil which was a very straightforward job.

The car is off to the MOT centre today, wish me luck...

Thanks,
Nick

 

[nblu]

Just a quick update, the car is back on the road. It failed its first mot on emissions as another coil pack was causing a misfire. Retest after replacing that pack and it’s all clean.

Looks like I’ll be looking at new rear shocks next as mine are corroded. I’ll be digging around the forums for recommendations next

Thanks,
Nick