N62 Z3 Part 12: Engine Refresh (Gaskets)

Finally my engine refresh parts showed up!

Also, for anyone curious, this is the Uro premium coolant expansion pipe. When installed in the engine the bottom pipe will slide into the top pipe. I'm happy with the quality, they are very thick pipes, I am not an engineer but it looks to me like there is built in redundancy with the three channels for coolant rings along the width there - the fourth cut on the far left is an indent for a locking ring, the kit even includes spacers to ensure a really tight fit. This likely tells me part of the intended design may be so if coolant does seep past these inner rings it will harden and seal again, although the end seals are still a single seal so its not like you are gaining any sealing ability with this redundancy. I guess the point of this design was to eliminate the cause of concern of the seam in the middle and I will say, at least for me, with this design that has been accomplished. And if the parts fit well in the engine, I will have confidence in the repair - the tolerances on the bench (literally, in this case) seem very good

I will also add, I have read through the Uro premium installation guide for the coolant pipe, as well as the AGA coolant pipe guide when I was deciding which to buy. I will be utilizing a technique from the AGA guide when it comes time to do the repair


First step was to clean up the engine harness a little bit

Chopped off the automatic transmission harness plug

Then started tracing those wires to the plugs in the engine harness side

As it ends up, this entire plug can come out

After all that, any loose wires were cut, loosely spun together and then heat shrinked in two layers of protection

So something I had observed earlier was the canbus system was not operating properly. I observed today that the canbus wires terminate here and can't help but wonder if they need to be made continuous... the diagrams seem to indicate that should work, but I will give it some more thought. Then wrapped up some of the engine harness just to make things a little tidier next time I am in the DME box

Then moved onto removing the engine harness off the engine and some pointless beautification as I went along there too. Normally these are hidden by a beauty cover, but I think I am going to leave the beauty cover off, so I'd like it to look a little neater

Once off I cleaned up and wrapped some of the damaged wires...

There's a vacuum line that runs through the electrical box... the part outside the box was a little damaged. I decided to trim the line and use a barb from the damaged engine harness I had laying around, to make both sides "barbed"

I then rolled the engine out of the main shop and cleaned it a little bit, things were properly masked (thus why things like the throttle body isn't wet...) and I didn't go at it very aggressively. It really wasn't very dirty, I'm pretty happy about that

And then got to work pulling some accessories off the engine... cleaning as I went

Water pump was remarkably clean. If I knew it was in this shape I probably wouldn't have ordered a replacement. Oh well. I'll keep this one as a spare. Block side is pictured exactly as I saw it when I took the pump off, no cleaning done before the picture. Gasket surface is a little dirty but the main coolant area itself isn't pitted which is great

These bolts for the grounds for the coils did give me some trouble... a little handiwork with the dremel turns what was a hex (rounded out before I got there) into a flathead, came right out

After some of that process completed

Not gonna go crazy detailing the engine, but these things have been bothering me for awhile so they will be getting sanded back and a lick of black paint over em

Once home I opened the boxes of parts to see what I was in for... it's both more than I was expecting and not as much, though some of the parts haven't arrived yet and aren't pictured

The engine stand finally came in so I split the engine from the transmission

Compared to a 420G from a V8 E39 I had laying around, since I've been asked by a few people how they compare...

First chance to look at the pressure plate assembly... noticing a lot of dust... not usually a good sign lol

Pressure plate and clutch off... flywheel not looking so hot

Pressure plate shows lots of hot spots, clutch looks pretty good overall, but with localized wear spots. Indicates to me that the owner likely sent it very hard right before he pulled the motor lol. Good for him haha

I can tell that most of that flywheel grossness is clutch glazing. It's not the end of the world if so, it should come off with normal driving once in operation and even if not - none of this swap so far has me thinking that a clutch job will be any more difficult than usual. So, my current thinking is send it with this flywheel and absolute worst case, replace it all when I have to down the road. The clutch has a lifetime warranty in any case


Then I ended up getting paused here which was very annoying. My sockets didn't fit in the flywheel well so I went and bought these deep socket Torx bits. Or, sorry, "Star sockets"

And I didn't have the correct lock pin for the crank pulley either apparently. I have tools for working on N62's but guess I didn't think much of the fact that my tools were valve stem seal tools, which do not include a lock pin tool and the lock pin tool which fits M50/S52 engines, even S62 engines and a lot of other BMW engines... did not fit the N62. Well, not in a way I found appropriate anyways

Conveniently enough, I had something on hand that was just the right size

So now I can lock the crank pulley so I can loosen the flywheel and get the engine on the stand

Took some thinking and certainly some wrestling to get that engine on the stand alone. Then I went to give it a test spin and realized the center of balance was way off, so I had to re-seat all the attachment arms, to lower it down to get it at a better location. D'oh. But that's one of those things you can't really test until you have it tightened down and don't know until you bolt one down... now I know


The first task was the coolant pipe. Actually was trying to record a video of that but my memory card filled up and it stopped recording halfway through... so these pictures I took during re-assembly will do and I decided to not try to record any more video for the duration of this build...


With the intake manifold off (fun fact, TIS doesn't mention having to remove the Valvetronic motors, I didn't see a way to remove the intake manifold without having removed them though) it's pretty quick work. Most the difficulty in this job with the engine in the car is getting to where you can remove the intake manifold, as that requires removing the wiring harness out of the way, which requires moving a bunch of delicate trim pieces out of the way


This is with the valley pan off and the old coolant pipe already removed. Note the shop vacuum head in the front water pump port of the engine - this was sucking up all the old bit of rubber coolant pipe seal I was scraping out with a pick tool and wire brush

New coolant pipe slid in place and marked with a sharpie before the seal is installed - this was the step I borrowed from the AGA instructions. The goal is to get the coolant pipe to sit flush to the timing cover - so you slide the pipe into place before the new seal is installed and mark it with a sharpie, that way you know when it is seated fully in place with the seal installed

New o-ring and seals installed... front one was a bear to get in place and couldn't get a clear picture of due to it's location

Coolant pipe installed

Bought a new torque wrench and this was the first job I got to bust it out on... all torqued down

And why not...

Spent a little time cleaning it too, nothing too crazy... just got sick of seeing all that surface grime and stuff on the aluminum so spent a little bit of time on it

Flipped it over to do the oil sump gaskets, first step was taking everything apart - it's always a little weird seeing an engine upside down!

I also wanted to do a new rear main seal before putting the oil pan back on. I was able to torque all but one of the bolts to spec with it on the engine stand - the bolts I torqued get marked and the one I missed was torqued by hand to roughly the spec, just in case, but it will be double checked later with a torque wrench. I also had the opportunity to line it up as flat as possible by using a straightedge, so I took a little extra time here to do so - this helps ensure the oil pan has a good seal here and also that it sits properly centered. These bolts get threadlocker applied

Then I also did the oil filter housing gasket before putting the upper oil pan back on with a new gasket

The lower pan was not fully tightened because I have new bolts coming for it, they just have not arrived yet... just a touch of bling... I didn't want to compress the gasket and then re-torque it later. I like it to be a "one and done" deal with these gaskets, so I will wait to torque until the new bolts arrive. A new gasket was fitted to the oil level sensor as well, although I am not sure if this sensor was damaged with the crank sensor mix-up, come to think of it, I will likely pull it back out, and replace it with a good one before final installation - just to be sure


I then did the VANOS solenoid o-rings and removed the alternator bracket gasket as well, although the alternator bracket gasket has not arrived so I could not finish that job yet

Camera got a little oily for a couple pics here...

Then I got the alternator bracket off, I have new bolts for it ready but I wanted to do some research before putting on another OE gasket

So later that night while looking up the alternator bracket gasket (I was hoping for some kind of upgraded design or material), I discovered the coolant pipe seal I used with my Uro pipe was a stock rubber type seal and there is a an upgraded seal for that available. The AGA coolant pipe seal is Viton which is supposed to be more durable so I ordered one of those, I also found out that Uro makes a Viton alternator gasket so bought one of those as well


Ripped the coolant pipe back out to install the upgraded coolant pipe seal once it arrived

Then I wrapped up some of the more basic engine maintenance stuff

The intake manifold is going on for the final time now that I have the new nuts for it, so I put new intake manifold gaskets on

New throttle body gasket

New vacuum pump gasket

New water pump pipe. Also new o-ring, gasket and bolts on the water pump

New harmonic damper bolts installed, I should have prettied this up a little more but these are pretty important to the engine, I was worried about sanding grit getting in between the layers of the damper and damaging it over time...

Getting there...

Then got some zinc bolts in the mail so I could slap the water pump pulley on

Alternator bracket gasket finally arrived and was promptly installed

Lower sump finally tightened down as well. I had zinc bolts coming in for these but they sent the wrong size, so I just said screw it I don't want to wait anymore... this pan is accessible from below really easily in the future with the engine in place anyways if I want to swap those out later I can. Removed the lower pan and cleaned the area again before re-seating the gasket and lower pan for final installation. Some blue loctite on the old bolts and they are good to go

Last job on the engine refresh is the valve stem seals... In the spirit of the budget build and because I am factoring in tools I have to buy for the build price of this car, I have decided not to buy an air compressor for this job. There is another way to do valve stem seals. And it's time to start that job! But first, I cleaned my shop...

Then got the engine out and ready to work on

Valve cover off