Hello NAM. I've been fighting this MCS for the last month and I finally got it back together today. This is more of a rant, but I'd like to share what I've learned during this horrible little adventure. Enjoy. TL;DR R53 presented with overheating, got a top end rebuild, turned out to be failed SC PTO.

So I bought this 03 MCS for my wife when we got married. She drove it daily until it was time to get her a new car and the Mini got passed on to me. About a month ago, her car was in the shop and I gave her the Mini while I drove my truck. One day, she wakes me up at 2AM saying the car is overheating and she barely got home that night. I drug myself out of bed, spent about 2 hours troubleshooting in the driveway, and concluded it was a failed head gasket. My thinking was that the failed head gasket was over pressurizing the cooling system. I pushed the teardown off to the next day and went back to bed.

Nightmare Machine Part 1
I'd done some work on this car before, including the clutch, coolant service, and brakes all around, so I was at least familiar with it. I pulled it into the garage, put it up on jack stands and began the top end tear down. I consulted a few videos and would like to pass on some of the tips I came up with during this part. So the first little bit I'd like to contribute is a list of the tools required to replace a head gasket:
1/4" and 1/8" flat tip screwdriver
#2 phillips screwdriver
T30 Torx driver
T30 Torx socket, 1/4" drive
1/4" ratchet with 8mm and 10mm deep sockets, 3" and 6" extensions
3/8" ratchet with 10, 13, 16, and 18mm deep sockets, plus 13mm flex head socket, 6" extension
8, 13, 16, and 19mm combination wrenches
5/8" spark plug socket
Small needle nose pliers
Slip joint pliers
3 and 10mm allen wrenches
12" pry bar
8" ty-wraps
Bungie cord
Floor jack
2 jack stands
100 ft-lb torque wrench

With just these hand tools, an average mechanic can disassemble and reassemble the top end of an R53 engine. Assuming everything is in working order, that is. But as luck would have it, 4 of the valve cover bolts rounded off when I tried to remove them. I had to drill off the bolt heads, break them off with a chisel, and remove them after the head was out of the car. Since I technically used these tools, I'm adding them to an extension of the list. They are:
1/8" and 5/16" drill bits
Cordless drill
8oz ball peen
Center punch
Chisel
1/2" ratchet
Stud remover

The removal of the head isn't exactly straight forward, and I'm not prepared to do an entire writeup on it, but here are some of the little things that made the job easier:
1. Your have to loosen, but not remove the supercharger to make room for the intake to clear. I didn't remove the accessory drive belt to replace the head.
2. Once the valve cover is removed and it's time to remove the cam sprocket, rotate the engine to TDC and use ty-wraps to secure the chain to the sprocket. Use a bungie cord to hang the sprocket to the hood. This will keep the chain from skipping on the bottom sprocket and save you the trouble of tearing apart the front of the engine to set the timing.
3. I sent the head out to get cleaned and decked at the local shop. It cost $60 and all the valves looked good so I stopped there. If you want to port/polish or just do a valve job, now would be a good time, but I didn't think it was necessary.
4. As always, replace the head bolts with new when replacing the head gasket. These are torque-to-yield bolts, so they must be run in by hand, torqued to the correct value in the correct patter, then turned an additional 90 degrees.
5. Pay careful attention when reassembling the cam sprocket. It has marks but they're a little hard to pick up on. Instead of using the BMW tool to hold it steady, I put a screwdriver through one of the holes to keep it from spinning. For shame! you say? Tough, that's how I did it.

The head bolt in the very corner of the #4 cylinder on the exhaust side was covered in burnt, grimy oil. I took this an confirmation that the head gasket had failed. I reassembled everything with new gaskets, changed the oil, filled the cooling system, and took it for a test drive.

And it was still overheating. F***.

Cold, tired, and with a broken spirit, I got it back in the garage and sat down with a beer and a laptop, trying to figure out what could possibly make this happen. I checked the water pump. Good. I tested the thermostat on the stove. Good. Clogged radiator? Blew it out with a garden hose. Good. Failed pressure cap? Replaced with OEM. Collapsing lower rad hose? Replaced.

With almost all of the cooling system either checked or replaced, I filled it back up and started it up to test. Still overheating. God. Dammit. I was seriously considering giving up at this point. I'd almost exhausted my options but turned to the forums to see if there was anything else, anything remotely possible that would cause these symptoms. An I stumbled across a thread.

R53 Mini Cooper Supercharge Rattle of Death

Nightmare Machine Part 2

Hmm, I thought, that sounds ominous. I HAD to know, so I went back out, tore the front of the engine apart, ripped out the supercharger, and put it on a bench. I spun the pulley, and the water pump PTO didn't move. I pulled the cover off the back, but I was not prepared for the carnage that existed inside. As some of you may have already experienced, this presented with the typical ground off drive gear, which was resting comfortably in the bottom of the gear case in a little pile of dust.

Now that I'd found it, it was time to knuckle down and fix it. I called about 4 supercharger shops, and they quoted me as much as $1500 to rebuild my SC. Nobody would replace only the gears. A new SC was more than $3000. This simply wasn't in the budget for an 11 year old car. So after a few weeks of research and a lot of emails, I was pointed to Invasion Auto. They make a set of PTO replacement gears only for $235. I cleaned and inspected everything, checked the seals and bearings, and since the SC lobes were almost perfect, decided this was the way to go.

Now for some things I learned about superchargers. The Eaton M45 is not the easiest thing to work on, but is not impossible.
1. The end plate gear came off with a medium sized gear puller without too much trouble, but the PTO shaft bearing was no longer fixed in the housing. Eaton presses the gear in and swages it in place. Once I removed the gear, I took a small ball peen and worked around the bearing race to peen it back over and secure the bearing. Working very gently on the soft aluminum plate, I was able to restore the lip that holds the bearing in place.
2. The needle bearing in the SC case seemed alright, so it was cleaned and dried in place. I did not replace it.
3. The drive gear was the real bear. I got turned away from 2 machine shops when I was trying to have it pulled. I tried drilling the gear out on a drill press, but it was harder than any of my drill bits. Unable to get behind it, I tried welding a puller to the face of it, but the gear broke off at the weld. Finally, I picked up a tungsten carbide bit for a dremel, and in about 20 minutes was able to cut in almost to the shaft. Then I cracked it with a cold chisel and was able to remove it.
4. To replace the gears, leave the supercharger and end plate somewhere cold overnight. Heat the gear in a toaster oven to 400 degrees (F). For the end plate, slip the hot gear over the shaft, bevel side down, and press gently into place. You can do this by hand. For the drive gear, press it on similarly, but you won't get it all the way. Use a long 8mmx1.25 bolt, nut, and washers to press the gear on. I finished it up with a socket so that the gear just cleared the bevel on the shaft. Allow everything to cool.
5. Since I figured the seals were OK, I assumed the gear oil leaked out the seam. Before reassembling, I pre-oiled the gears and needle bearing with synthetic 90W, then sealed the end plate with high temp RTV. Once the RTV cured, I topped off both the front and rear cases with 90W.

From here, everything was reassmbled, topped off, checked and rechecked. I did have a problem with a fuel injector leaking, but it was just that the O-ring wasn't seated properly. Corrected that, started it up, and bled out the cooling system, aired up the tires, and took it for a test drive. So far, so good. Now I can clean up my garage and put that thing back on the road where it belongs.

For those of you out there with the supercharger death ratter, dreading the idea of spending almost $3000 on a replacement, I encourage you to consider replacing the PTO gears if your SC is in otherwise good condition. Or if you have a failed head gasket, taking the job on instead of going to a shop. I hope this little adventure of mine can help out somebody else who's having trouble with their R53.

Thanks for reading. I'm feeling much better now.

 

Good work!!
Not sure where you got sc rebuild quotes, but $800-900 is common for a quality job from waymotorworks or stegimer....
Sounds like you rebuilt the most often neglected system on the mini...the cooling system!!
Since so few folks ever drain/fill or flush it, I would have bet $$ you head gasket assumption was right...
Too bad nobody notice the sc gear notices before they failed entirely and went silent....would have made trouble shooting easier!!

 

By using 90 weight oil in supercharger might you not have to change it out and use the Gm or eaton special oil. Will 90 weight work as well as the special oil? just asking.

 

Not sure how the 90w compares to the Eaton oil. Hopefully it will work out ok. There's 135k on the car now, if the SC makes it to 200k I call it a win.

 

Great writeup buswork, thanks for sharing.

 

Nope 90 wont do. There will be another right up here soon I assure ya

 

As soon as it blows up, I'll update the thread. Until then, any oil is better than no oil. How long have you been rebuilding superchargers animal? jk, best case it's a good science experiment.

 

Haha, actually I would not be kidding about calling people out on their expertise. There are so many self professed PhD arm chair experts here that have never lifted a wrench (or have any knowledge of mechanical engineering), but they just go on reading these forums and treat everything as gospel. It's silly.

 

Eaton
FAQ for Superchargers
Q: How often do I need to change the oil in my supercharger?
A: The sealed oil reservoir in a supercharger is designed to last the life of the vehicle. Changing the oil is not recommended unless you suspect contamination, leakage, or other issues like bearing failure. Also, if your vehicle has an abnormally heavy duty cycle, such as racing or towing, you could consider changing the oil at regular intervals such as 20k, 30k, 50k, or 100k miles depending on usage.
Q: I’ve decided I need to change the oil in my supercharger. How do I do this?
A: If you do want to change the oil there is one fill/drain plug on the front face of the front cover. It will probably be an Allen type plug. You will have to suction out the oil using a syringe or other method before replacing with new oil. Fill levels are dependent on application. For aftermarket units, please consult the aftermarket partner company that produced that specific kit. For OEM units, please see the list below or email infosupercharger@eaton.com. New oil can be obtained from any GM or Ford service parts facility, or from one of the Eaton aftermarket supercharger partner companies or re manufacturers. Please make sure you do NOT use any other type of oil, including synthetic motor oils. These will cause failure.

Straight off the EATON website.

 

However, I find it interesting that you claim Supercharger oil is a synthetic and yet the Eaton missive you quote says not to use synthetic (motor oil - yes I know the difference). I also thought the point of gear oil was that it clings to the gears, why would you want it to mist? I will say this, having changed the oil in more than a few superchargers on MINIs, there is very little oil kept in the water pump end of the supercharger, especially compared to the drive end. But the mist thing puzzles me.....


I know one thing, that stuff stinks like a nasty old sneaker that's been left to mold over a long hot summer in a locker when you drain it out!


I also wonder how the OP determined the seals were OK - I'd want to know where the oil went and absent some positive proof (like a trail of oil) I'd seriously doubt it came out of the end case cover. It's far more likely it got sucked out thru some worn seals......at least to me.


OP, no pics of the carnage? Especially the gears?


I agree with a couple other posters who mentioned that the noise from the dry gears should have been clearly audible, and reacting to that noise would have saved the head gasket job.


BTW, for those who look at the lobes to determine if the SC needs rebuilding - I suppose that's a good indicator - but the only way you'd see wear on the lobes is if the bearings were totally shot - I would think you would hear them long before then.....


One last point in case anyone is still reading, a failed crank damper will cause overheating too, as it when it fails it no longer turns the SC, so it no longer turns the water pump. The engine still runs OK, but the lack of power, and the alternator light on are the other tip offs.

 

The thing that makes this interesting is...
The mini m45 has 2 gear sections....
All the other Eaton units have JUST THE SNOUT, that runs at very high speeds (rotors can go as 20,000+ rpm if i recall right) and needs thinner oils....to prevent foaming, sheering, etc...
BUT THE OP put the 90 weight gear oil in the PTO, which runs pretty slow...
So it might just work...
Heck might be a "solution" to many issues...
The OP SPENT HIS FREAKING MONEY..aka yfm...
So while I would not have thrown the dice, I can only say good luck!! It is not suggested, but he has done some great work, WHY NOT!

 

Why can't we all commend buswork for the good job he's done. Who knows, the 90w might just work. There was a thread on new JCW chargers for just $1k shipped. Dunno if they're still available, tho:
https://www.northamericanmotoring.co...r-5th-gen.html

 

The original post was a fantastic read. Great work, way more than I would / could tackle on my own.

 

I'm terrible when it comes to snapping pics of progress, but here are the few that I did take in an Imgur album: https://imgur.com/a/5jkVz

A couple responses to some above comments:
MINIDave: I also wonder how the OP determined the seals were OK - I'd want to know where the oil went and absent some positive proof (like a trail of oil) I'd seriously doubt it came out of the end case cover. It's far more likely it got sucked out thru some worn seals......at least to me.
I had grand plans of rigging up a hose fitting to the case drain, pressurizing to about 15psi, then seeing if it held pressure. But I was getting impatient so I just relied on a visual inspection. The seals may have been worn, but they didn't have obvious damage. The hope is that the 90w is thick enough that it won't get sucked into the SC, won't leak out to the waterpump drive, and since I sealed the plate, it will stay in the gear case.

MINIDave: I agree with a couple other posters who mentioned that the noise from the dry gears should have been clearly audible, and reacting to that noise would have saved the head gasket job.
Heard it, thought to myself "That sounds funny, wonder what it is?" and promptly did nothing. Whoops.

MINIDave: BTW, for those who look at the lobes to determine if the SC needs rebuilding - I suppose that's a good indicator - but the only way you'd see wear on the lobes is if the bearings were totally shot - I would think you would hear them long before then.....
Visual inspection of the lobes is what drove me to repair rather than replace the SC.

MINIDave: One last point in case anyone is still reading, a failed crank damper will cause overheating too, as it when it fails it no longer turns the SC, so it no longer turns the water pump. The engine still runs OK, but the lack of power, and the alternator light on are the other tip offs.
Totally agree, but the alternator was charging and the SC was making boost. Failed crank damper was not the problem.

ZippyNH: BUT THE OP put the 90 weight gear oil in the PTO, which runs pretty slow...
Actually, I drained out the snout end while it was off the car and replaced that with 90w too. If one side fails before the other, I'll update to let you know what happened.

I realize Eaton recommends specific gear oil, but so far, so good with the 90w. But if it ever goes bad, we're blowing up superchargers... FOR SCIENCE!

 

I replaced the supercharger gear case lube with Redline MTL approximately 32,000 miles and almost 3 years ago. Had no other choice because gear cases were found to be dry & Red Line was the only option available. Lesson learned, don't try this on a Sunday night when everything is closed. Apart from a more pronounced supercharger whine (not a bad thing), no noticeable issues. My 2004 MCS just had its 11th birthday and just passed 120,000 miles.

 

I say good work and good write up, sorry your mini has fallen to the chewed up PTO gears

 

100 mile check in. Still running, no splody.

 

Threw the drive belts weekend. Finally removed belt remains today. Noticed some "chips" on the ribs of the supercharger pulley, any way to replace this pulley? 06 R53 w/102k

 

Congrats on having the patience and knowledge to tackle the supercharger on your own. I was lucky enough to catch my supercharger issue before doing any damage to the engine ('03 MCS, 85,000 miles). I just had mine rebuilt this past August at the tidy cost of $1,500, since it's way above my ability to do this on my own. I used AutoXCooper.com - they seem to know what they're doing and are pretty passionate about Minis. One year warrantee as well. Seems like a good option for those of us that aren't able to do the work on our own.

 

So so true! Nevertheless, one thing I'd like to add though. You don't have to worry about the chain coming off the crank shaft sprocket. The timing cover has a lip that keeps the chain in place. Just don't rotate the crank and you'll be fine.

 

Sulfurized oil (cutting oil used in thread cutting machines..yes I'm a retired plumber) stinks a lot. Cutting oil that is sulfurized has cooling tendencies. That may be an additive in the supercharger oil. (just a guess on my part)...

 

Good job on everything! I was also reading about supercharger oil- looks like the Cobra SVT guys have had good luck with 10w30 synthetic...

 

When I first read Buswork's post, I thought it was a HOAX from Stiegemeier or Embree or Jon Bond or Ed Martinez (PSE) or some other self proclaimed Mini M45 hack. However, the length of the diatribe ruled them out because they don't have the time nor inclination to give away the valuable??? technical??? information that Buswork provided. Beware, everything that Buswork offered will get you into trouble. My problem with Buswork's nonsense is that he/she and others like him/her will sell the poor little Mini to an unsuspecting person who will inherit the pending high repair cost! Shame on Buswork and those who encourage him.

 

What nonsense, pray tell? He fixed his vehicle. It runs. When/if he sells it, it's up to the buyer to ask the right questions and take due diligence. Anyone who purchases a high mileage vehicle should expect worn parts that fail. Caveat emptor. Life, itself, is a gamble. There are no guarantees and no warranties on original body parts.

 

We're all gifted in many different ways. Some got tech skills, some got people skills, some talk, some walk....rarely all in 1.....ironically, respect is easier earned with humility. Let's all give credit where it's due. The OP simply shared his experiment w/ positive results. No point in putting anyone down. That said.....peace & Merry Christmas.