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 Amazon.com 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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BMW E61 Turbo Replacement - Pulling the N54, and Stripping the Engine

Once all the electrical and plumbing was out of the way, and the exhaust, heat shields, driveshafts and drive axles removed, it was time to pull the engine. I initially planned to leave the transmission in the car, but a leaking rear transaxle seal made me decide to pull it out with the motor. We hooked up the engine hoist to a load balancing beam so that we could easily change the lift point with respect to the center of gravity. This ended up working very well, and was essential when pulling the transmission with the engine. 

Starting the lift - this is as far as you can go without lowering the steering gear and engine support crossmember

One we started lifting, we quickly realized that the X-Drive front differential would not clear the steering box of the steering gear with the lower crossmember in the car. As soon as we dropped the crossmember - the engine and transmission popped forward without much effort.

Engine and transmission out of the car - complete with front differential and transaxle. Heavy combination.

Next step was to separate the engine from the transmission. We were having difficulty with this - and thought that we had left a bolt in - which ended up being the case. We actually snapped one of the aluminum bolts clean in the engine - the head was hidden behind a gusset on the side of the transmission - we didn't see it with the transmission resting close to the floor. This ended up not being an issue - as all these bolts need to be replaced anyway, and the broken bolt backed easily out of the hole - no problem extracting.

Transmission on a dolly with castors, steering rack and crossmember on the ground.

Beer time.

First order of business before putting the engine on the engine stand was to remove the rear crankshaft oil seal. I thought this had been leaking, but it turns out it was still sealing well at 185,000 km. I bought the new seal and will replace the seal anyway. You can see oil coming down from the top right of the head through the gap between the engine and the bellhousing - this oil was coming from the area of the rear turbo.  

This seal pops out easily with the assistance of a couple of screws drilled into the seal. 

Claw hammer to remove the seal using the screws

Old oil seal - oil grooves are still in reasonable condition. Will replace anyway.

Since all the fasteners on the block are going into aluminum, and my torque wrenches are about 25 years old - I decided to check and calibrate the torque wrenches before I took down my engine crane. I just clamped a small vice to the arm of the crane, and held the socket of the torque wrench in the vise. I then loaded the torque wrench using a 5 gallon bucket of water and steel weight - adding water until the torque wrench would click. I would then measure the weight of the bucket, and apply the factor of length to come up with the actual torque. My 1/2 torque wrench recalibrated nicely with a small adjustment, and I'm within about 2% of torque. My small 3/8 torque wrench seems to have lost it's linearity across the internal spring - I could not get it to 5% across the measurement range and discarded the wrench. Quick order to Amazon to get the Tekton 3/8 clicker torque wrench to get me through the job. 

 This morning I got onto removing the turbos from the block. This went pretty quickly without much hassle. One thing that I've noted with this whole process however - is that it's really handy to have a few different sets of torx and e-torx bits - because sometimes you need a long bit, sometimes you need a small short bit, just to fit into the limited spaces where you're working.

Short 1/4" drive torx bits to get into tight spaces. 

Long torx to get at the manifold bolts. 

 It took about 2 hours to strip everything off the right hand side of the engine, including the bearing support for the front right drive axle, and the differential from the other side.

 Two of the exhaust manifold studs stuck in the block with the E-Torx head broken off - needed to jam 2 nuts together to get these last two out.

Jamming 2 nuts together to remove last two exhaust studs.

 Oil stain on the front differential was coming from the top vent. I'll be replacing the vent along with the seals - already have the vent on order.

 Removing the pan was fairly quick - had to remove the power steering pump first.

Turbos, oil and cooling lines, differential and oil pan removed. 

 New problem encountered - looks like my head gasket is leaking oil from the front right corner of the motor. The area below the head gasket is wet, and I don't think it's come from anywhere else. With everything off the engine, especially the turbos, now is the time to do this.

More to follow. I'll start with replacing the front and rear main oil seals, the oil pan gasket, and do the intake valve walnut blast. I'm researching what's involved in doing the head gasket now.....

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 Amazon.com 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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535xiT Turbo Project - Ready to Pull the Engine

It's taken me about 3 full days to get to the point where I'm ready to pull the engine. I'll share a few of the observations / problems I've made or encountered. 

Starting with the removal of the exhaust - I was really worried about the state of the exhaust nuts joining the downpipes to the midpipes. These looked like they were frozen and I was dreading this step. 

Downpipe to midpipe hardware - note the rust

I managed to impact off three of the nuts with some effort, and completely rounded the fourth nut. I tip for anyone doing this - particularly a Canadian car which lives in road salt a third of the year - do a really good job of cleaning up the nuts and soaking the hardware in solvent (PB Blaster or equivalent) before trying to removing these. Get on the hardware with a steel brush to try to get the nuts back to original size, the fastener I rounded off was enlarged with rust, and I think I used a socket size larger than I should have.

Rounded exhaust joint nut....

 So - I went through my toolbox looking for a solution for the rounded nut - and found my set of metric 12 point sockets that I bought at a garage sale about 10 years ago for $10... I pounded the 10mm 12 point onto the rounded nut with a ball pein hammer - and then gave it with the impact and managed to get the nut off. That made my day.

This will need to be replaced, along with the studs.

 I then removed the rest of the exhaust. I had some severe corrosion in this brace plate which bridges the bottom of the exhaust / driveshaft tunnel under the rear seats near the rear differential. I also had some massive heat shield corrosion. I've never removed my underbody splash shields for spring cleaning to remove road salt - and I can see why it's recommended practise. This brace and hardware will be replaced.

 Onto removal of the driveshafts. No real difficulty here - put the transmission in neutral using a screwdriver next to the shifter, and removed all the hardware with my 3/8" impact. Front and rear driveshafts dropped out without an issue. Use marking paint to index the location of the driveshafts before removal. It looks like I have a leaking transaxle rear output shaft seal - see photo below - will need to take a closer look at this.

Leaking Transaxle rear output shaft? 

 My rear differential has a leaking input shaft seal - this will be replaced before I put the driveshafts back in. Left and right output seals look okay - I'm going to avoid the rear end with this job and do that in the future.

Rear differential - input shaft leaking

 I then set out to the front drive axles - left and right. You have to detatch the lower control arms to pull out the steering knuckle enough to pull the axles out. You also need a hub mounted tool to push out the axle - I was surprised how much force was required to push the axle out of the hubs. My new favourite tool is this Dewalt 20V 1/2" impact..... Lots of power on all the tough fasteners. I also found that my torsion strut bushings were shot and need to be replaced - could be the source of the front end vibration at speed that I was experiencing - so I've added bushings and ball joints to the list of things to do when I put the car back together.

Pushing out the front drive axles from the hubs. 

Driveline carnage - Front and Rear Driveshafts, Left and Right Axle shafts. 

 In prep for pulling the engine - you have to remove the intake manifold to get access to the rear engine lift point on the block, and to remove all the electrical connections under the intake. My turbos were leaking oil through the charge air tract - here's what I found with the intake manifold removed (no surprise, I already have the kit to do the walnut blasting in the gararge). I'll do the walnut blast with the engine out of the car and on the engine stand.

Number three cylinder intake valves.

 Removing the electrical wiring prior to pulling the engine. I found some forum discussions where guys removed the connections from the ECU compartment, so they would have to disconnect all the discrete connectors on the engine. I tried this - and quickly found that it didn't work. The power leads and the grounds in the engine harness don't terminate with disconnect plugs that are accessible in the ECU compartment - you have to dig and split harnesses in order to actually make a clean disconnect. So I ended up reconnecting the ECU terminals - and went to pulling all the discrete connections on the engine. This wasn't that hard - and I used paper tags to label the connections that might be hard to identify later.

Engine harness disconnected from the engine - lying on top of the right side inner fender. 

 The last thing I did was to make sure all the hydraulic and cooling lines were disconnected and free of the engine - transmission cooler lines, power steering lines - all disconnected and moved out of the way. I've been noting all the O-rings and seals I'll need on reassembly - I'll do another post on that topic later in the week.

N54 engine ready to pull. 

All that's left to do is to remove the bellhousing bolts, and the engine mount bolts. I've already got the torque converter / flex plate bolts removed. Looks like I'll hit this on Thursday.

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 Amazon.com 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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BMW 535xiT Turbo Replacement Project - Prep for Pulling the Engine

I've gone past the point of no return now - will be pulling the engine to do the turbos, oil pan gasket, rear main seal, and as we'll see, maybe the front main seal as well. The past week I've pulled the bumper cover, radiator, air conditioning condensor, and all the coolers in front of the engine. Here's some photos showing what I've found.

Starting with the intercooler - this part is really easy to drop from underneath the radiator - you can do this with the bumper cover still in place. I estimate that the fins were about 30% blocked by a greasy slime of road grit and bugs.

Intercooler - removed from car before cleaning

 With the front bumper cover removed, you have acccss to the headlights and reinforcement bar. Removing the bumper cover isn't too difficult on LCI cars - 2 screws in each wheel well, 2 screws behind the inner fender up underneath the side of each headlight, 4 screws along the front above the fog lights, and about 5 screws along the front top underneath a plastic trim / seal panel.

Bumper cover removed

 Note the corrosion on the mounting sleeves of the SRS impact sensors, to the right of the headlight washers.

Headlight washer and SRS impact sensors

 SRS impact sensor corrosion.....

SRS impact sensor corrosion

These will need to be replaced, and I'll replace the hardware for good measure. 

 With the front reinforcement bar removed, I removed the AC condensor, radiator, transmission cooler, and power steering cooler. Note the crud along the bottom of the radiator.

Radiator - bottom 2" blocked with oily bug sludge

 As I'm proceeding with removing all the plastic trim parts, covers and hoses, I'm washing all the grit and grime off the parts so that when it comes time to put the car back together - everything can go smoothly. Nice thing about the wagon is that there is lots of space for all the plastic bits.

Parts removed from the car - cleaned and prepared for replacement.

 The transmission cooler won't be salvageable - the fins are completely blocked with road grit which didn't dislodge during cleaning. Since I won't be spending a few hours with a toothpick trying to clean each fin, I'll be replacing this part.

Tranmission cooler - completely blocked with road grit.

 With all the coolers removed, we can see the front of the engine nicely. I have a few more hoses left to remove, then I'll transfer my attention to removing the exhaust and getting ready to drop the transmission to access the bolts that fix the engine to the transmission.

Reinforement bar, headlights, radiator and coolers removed. Almost ready to pull the engine from up front

Looks like the front crank seal is weeping oil - hard to tell. Will see when I get the balancer off. 

 Organizing all the fasteners - I have some Plano tackle boxes which I've numbered the compartments. Every step of the way I'm noting my progress in the green notebook, and noting the hardware removed at each step. This should make reassembly easier.

Plano organizers for hardware

 There is about 15 to 20% of the steel hardware which is corroded and will need to be replaced. I'll look up all the fasteners on RealOEM and put in an order through my dealer for these.

Hardware removed from the car. 

 I have a pretty good view of the intake side of the front turbocharger - note the crud below the inlet - this has been leaking oil for a while. Will be interesting to see what this looks like when the engine is out of the car.

Front turbo - inlet side. 

More to follow - I'll do a post every few days as I proceed through this.

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 Amazon.com 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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