BMW E61 Turbo Replacement - New Head Gasket, Oil Pan Gasket and Oil Level Sensor Gasket

So this is the point where your spouse really begins to think that you're crazy, and wonders when you're going to get out and get a real job....

Since we're this far into it, by this time I had made the decision to switch out any suspicious seals, gaskets, o-rings, and try to do a proper job of this. I separated the head from the engine. You need to remove the timing chain from the VANOS camshaft gears. In order to remove the camshaft gears, you need to lock the camshaft into position using the camshaft lock tool - part of the camshaft timing tool set for the N54. Procedure is as follows - move the engine to top dead center cylinder one - and you can make sure you're in top dead center by looking for the laser engraved part number on the camshafts - just behing where you insert the camshaft locking tool. If you can't see the part number - you're 180 degrees away from top dead center and won't be able to remove all the head bolts. 
With camshaft in TDC position - grooves in the camshaft allow access to the head bolts underneath
Unbolting and torquing the heads - you're going to need a set of long hex sockets to access the fasteners. I kept the camshaft lock on the head the whole time the head was off during cleaning. 

Head split from engine. Note the camshaft lock tool (black).
With the head off - it's time to get everything cleaned up. I used brake cleaner and very mild abrasive scouring pads to gently remove the oil and carbon deposits. It worked well.

N54 engine block with head removed. No major difference in carbon buildup on the pistons. Note the zip tie holding the timing chain to the timing chain guide - this prevents the timing chain from falling off the bottom sprocket.
 The head gasket has factory applied silicone sealing rings applied. With the old head removed, I could see some places where oil had started weeping past the head gasket.

Front of the block - oil weeping past head gasket - timing chain cavity
 When I got down to cleaning the engine block - I cut fingers from vinyl gloves to block the coolant passages and help prevent debris from getting down into the coolant and oil passages. Very important - make sure you remove all this before you reassemble the engine for obvious reasons.
Vinyl glove pieces used to seal oil and coolant passages from debris during cleaning.
With the block mating surface clean - now is the time to check that the block is flat using a machinist straightedge.

Engine block cleaned, ready for head gasket and head.
 On to cleaning the head. This took quite a bit of effort to get the mating surface clean. When you factor in the time required to clean the oil from the intake passages (walnut blast) - in retrospect - I would have had the block taken into a machine shop for disassembly, cleaning, and a cleanup cut off the head surface. For the money I would have spent - it would have saved 40 hours of work in my garage... live and learn. I'll do a post on the intake valve cleaning and the problems I ran into there.
Head cleaned, ready for inspection and verification of flatness. 
 I had three places in the head where there was very minor erosion of the aluminum surface. Best option would have been to take the head into a machine shop to have a cleanup milling cut done. I cleaned the erosion the best I could, then applied a very thin coat of copper gasket maker to the eroded surfaces in the hope it will improve sealing of the head gasket. Time will tell how well this works.
Copper gasket sealant on a few eroded surfaces of the head. There was no erosion anywhere on the block.
 The assembly of the head to the engine was straightforward. Make sure you use new fasteners - they are all torque to yield fasteners and can only be used once. Torquing those fasteners is a bit tricky - you apply an initial torque with a torque wrench, then a defined turn in degrees. Make sure you follow the manual for your car for your torquing instructions.
Plastic valve cover, aluminum oil pan. Cleaning up for reassembly.
 Initially I thought I could get away without replacing the seals on the oil level sensor, so I left it in the pan and set about to cleaning the mating surfaces. Same procedure as for the heads - brake cleaner and scouring pads.
Mating surfaces cleaned on the oil pan - ready for reassembly with new gasket. 
 The aluminum oil pan gasket fasteners are aluminum torque to yield type. They take a very small initial preload - I used my 1/4" torque wrench from my bicycle repair kit to do the initial preload.
1/4" torque wrench on aluminum oil pan bolts. 
 To apply the 60 degree turn following the intiial preload, I did a wrap of vinyl tape around the torx socket - and made two marks 60 degrees apart. Makes measurement of the final angle torque application very easy.
 I followed up with a new magnetic drain plug.
Magnetic drain plug and sealing washers. 

Oil level sensor port - very dirty. Ended up having to purchase a new O-ring and clean this up properly.
Oil level sensor port cleaned up - fair bit of minor pitting, but the o-ring sealing surface wasn't too bad. 
I cleaned up the sensor instead of replacing it. Much gunk inside, came out nicely with electrical contact cleaner (safe for plastics). Looking at this - this is another good reason not to try to push oil change intervals on a turbocharged aluminum VANOS engine - you can see the effect that running high mileage oil has on internal components.
I used electrical contact cleaner to flush out the inside of the oil level sensor - worked well to get all the old oil out. 
A little copper silicone gasket sealer on the o-ring surface to help ensure a good seal of the level sensor despite the pitting.
I'll try to get a few more posts done - lots of lessons learned with this project that I want to share.

Sources and Links

I hope you found this post useful. Feel free to ask questions in the comments section below. I answer all questions. If you're interested, you can help support this site by using the following links to in the United States. Turbo parts were supplied by Turner Motorsports. Other parts were supplied by Pelican, BMW Park Avenue in Brossard, and eEuroparts.


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