Everything was working great then developed another oil leak. Apparently the valve cover gasket on the other cylinder head was damaged too so oil started to pool inside the V and eventually ran down the transmission bell housing on the other side. So close to being finished! The box of pending parts for replacing are dwindling.

Special thanks to @mercedesmorten for helping me re-initialize my trunk auto open/close function and identifying which PDC sensor was bad via STAR.

 

Update:

Spent the long weekend fixing the valve cover gasket so hopefully no more oil leaks!
Couldn't clean all of the residue off the exhaust so I'll just have to drive around and burn it off.

Also installed Sonnax overlap valves and TCC damper valve. Shifts much smoother now and reverse seems stronger (before it seemed like I needed more gas to get the car rolling backwards). Did the conductor plate and connector while in there. Connector was moist, but not soaked. Most of it seemed like oil from the oil leak.
Detailed the engine bay the best I could too so if there is another leak, it'll be obvious. Replaced the bad PDC sensor so front PDC works now without annoying beeps when there was nothing up front!

Spent today detailing the car.
- Hand washed
- Removed side V12 badges
- Mother's R3 tar / rubber remover on the front bumper and side rocker panels
- Clay bar on the entire car
- Hand polished some scratches with M105 (works great!)
- Removed years old caked on wax on the door trim using M105 + elbow grease since it wouldn't come off with clay bar or brush
- AmmoNYC Gelee wheel wax
- water based tire shine
- AmmoNYC Skin sealant

Car could use paint correction to remove swirls, but I think I'll wait until I replace the front bumper with an OE unit in a few months. Debating on going stock S600 or S65. S65 bumper will be more than double the total cost so I'm not too keen on that.

Now that the car is in a running state, my itch to mod it is starting. Kleemann tune for over 100 additional HP and ft/lb is $600 right now: https://www.ebay.com/itm/KLEEMANN-Me...e/292637579316
I like the idea of having 625HP and 700lb/ft, but knock on reliability is holding me back. Haven't really read any reports of issues from tuned M275 cars so maybe I'm just being paranoid. Would install a better IC pump if I go this route. Already have the 010 OE pump.

A few pics:

 

Bravo!!! It looks terrific!

 

Good work! She's coming back together! Glad to see that car go home to the right owner.

You should definitely look into retrofitting the full AMG body kit. It completely transforms the look of the car and flows really well with the body lines.

 

Car had developed a really bad noise which sounded like growling / howling / whining. Based on reading, it was a batd accumulator. Only issue is all my accumualtors were new. Was hoping it wasn't the pressure relief valve.

Started to take the front accumulator off to check it but then noticed the ABC pulsation damper hose (hose to nowhere) had vibrated a bracket nut off and was loose against the engine carrier. Put on a new nut, tightened all of the various brackets holding ABC lines.

Voila! No more noise! Crazy how a loose hose bracket can cause such a scary noise.

 

Wow, that's a belter! great work, looks like it's just come out of the showroom.

 

New issue has cropped up (technically 2 but the second I'll troubleshoot later).

Noisy ABC Pump:
https://youtu.be/KJp5tlqk18c

Only present upon cold start in the morning for up to 60 seconds before it quiets down to where it is not audible. Cold start after a work day doesn't cause the noise. Only in the morning.

Anyone recognize the noise? When it started, I got the ABC light twice. Hasn't come back one since. To me, seems like this rebuilt pump is no good :-(

 

If it is the abc pump thats causing the noise ...sounds like its internally catastrophic. I would definitely investigate. Any metal shavings or particles in the abc fluid?

 

Finally had a chance to check. No metal particles or shavings in the filter that I can see. I replaced the filter for good measure and replenished some fluid from the filter change.

Will see if it continues.

 

While it is certainly possible, that actually doesn't sound like an internal pump noise to me - too thin, sharp, and rattling. My first suspicion would be the idler pulley. Perhaps a strong drag from the alternator shoving an initial charge into the battery, causing the belt to be a little loose on the idler?
Use a good flashlight to watch the idler pulley and arm, and the rest of the belt and pulleys, to see if you can spot any movement.

 

Update on a few things:

1. I had an issue with the idler pulley because the hole was stripped and the bolt came slightly loose which caused the pulley to not be tight against the cylinder head. That was causing the noise at cold start up. I've tightened it again and it seems okay for now. Belt had some wear due to the loose pulley, but works. I'm going to have to drill out the threads and put a nut-sert into the cylinder head. I'm hoping there is enough space for me to use my 90 degree angle drill to get in there without removing the radiator. That radiator is a real pain to get in and out. New pulley, pulley bolt, and belt is ready to go in once I figure out how to drill out the cylinder head.

2. I have an intermittent A/C issue (DIAGN. FRA A ERROR 1426). Can't seem to find too much information on this code. Happens more often when I'm not moving and the car idles. Once I clear the code, A/C works again until the next time it errors out. There use to be other codes pointing to rear evap sensor, but that's been replaced and that code hasn't come up since. System was punctured (while not running) then repaired / refilled so either it's something in the system being damaged due to it getting air into it for a few weeks before repair OR the pulley from #1 is still a bit off and the system detects some kind of irregularity in compressor pulley when it engages?

3. When I leave the car for 3 to 4 weeks, the right side will droop all the way down. Firing up the car will get it to self correct. I guess since it's the right side, sounds like an issue with the ABC valve block? Both front and rear on the right side will droop down so is it just the front block or could it be the rear block as well? Need to review line diagrams again to track down potential culprit. I rebuilt both blocks, but it's possible I damaged some o rings / plastic washers when installing.

4. There is still a slow oil leak somewhere I need to track down. Doesn't affect oil level much, but it's just annoying have a wet undercarriage. Leak is aft of the front splash shield since the front one and oil pan is completely dry while the rear shield and some of the ABC lines above it are wet.

5. After about 4k miles of driving, my low coolant light went on. Coolant system seemed fine and kept an eye on temp. No issues. Once cooled down, noticed the coolant level was indeed low, but nothing alarming. Topped it off with less than a quart and no more issues. Intercooler system seemed fine and fluid levels were full. During an oil change today, I noticed the driver side engine mount has coolant residue all over it. I looked around and it wasn't obvious where it was coming from. Looking at diagrams, the only coolant line above the mount seems to be the intercooler hard line? The lines coming out of the radiator system looks dry. I'll take the airbox out to look around for other potential sources of the leak. Assuming it's the coolant system and not intercooler system due to the low coolant.


I feel the car is fairly solid and I wouldn't hesitate to take long drives with it provided I keep an eye on the pulley tightness and coolant levels. I've done round trips from LAX/SFO and LAX/LAS

 

There is a plastic fitting in the heater hose going thru the forward firewall (there are two bulkheads or firewalls on the W220) that is a pretty common failure point.You have to go in under the wiper motor assembly to get to the black plastic fitting, and it is very difficult to see the leak on the fitting.

 

Is this the "duo valve" I've read about before?

If so that might explain the sometimes erratic rear heat I completely forgot about.

 

No - The duo valve is the dual-solenoid valve that controls the left/right coolant flow to the heat matrices in the dash. The plastic fitting that often fails is the fitting that gets the coolant hose through the forward bulkhead to the duo valve. If you have separate rear heat, there is a separate duo valve to control left/right flow for that.

The plastic fitting is not "the cause" for your leak - it is one possible cause, and is a common failure. There are numerous hoses, clamps and devices that contain and control coolant in the HVAC system.

https://www.benzworld.org/threads/re...#post-16241098

https://www.benzworld.org/threads/sm...#post-17554047

 

I have never been 'impressed' with either the initial quality or longevity of 'rubber' components of all German vehicles. This has been a lifelong puzzle. German chemical technology has the best 'oxidation inhibitors' for polymers like rubber but for some reason they do not use enough. GM rubber 20 years old looks new. Interior plastics also endure. MBZ stuff crumbles away. Germany has restrictions on allowable age of tires (5 yrs?) while U.S. is silent.
IMHO, the best 'preventive maintenance' you can do for the V-12 S series is to heat shield all the ABC hoses and valves however you can. Even stuffing fiberglas and foil house insulation around things and then wrapping with plastic wrap or tape and spraying with rubberized 'undercoat' for durability. I used Aircraft 'firewall fire-stop' aluminized woven asbestos cloth for the ABC hoses everywhere I could. It is not oil or air temp, but radiant heat that destroys the hoses. That 'radiation' causes the chemical polymerization reactions to continue, destroying the rubber/polymer. Also regular oil and filter change in the ABC system is vital to long life.Old oil will attack the 'O-rings' and seals in the system and cause leaks. The accumulators WILL go flat every few years--that is a normal characteristic, and HEAT accelerates it). The nitrogen pre-charge gas dissolves into the rubber diaphragm and then dissolves into the oil, just like air slowly leaks out of a tire.

 

Another update
Almost destroyed the car yesterday from overheating 😅
Coolant level seemed okay and I had reinstalled the fan after changing the belt and re-torquing the pulleys. Then washed the car and took it out.

During the drive, the ABC system suddenly started acting up. Shocks were raising and lowering erratically and ABC warning goes on. Checked fluid levels and restarted the car. The more I drove on, the better it got. I must have gotten something wet and caused an electrical problem?

During my drive home, I was paying attention to the ride quality to see if it changed. Everything was normal. Then, out of the corner of my eye, I saw the temp gauge at 120c (before the red mark) and thought "that doesn't seem right". As I drove, it crept up. Was in stop and go traffic so couldn't pull over anywhere. Immediately turned on heater and temp dropped back to 100c but started to creep up slowly again.

Will be spending today diagnosing the issues. My guess is the fan connector perhaps wasn't plugged in fully or I shorted out the fan and the ABC system had an electrical issue from the wash.

I also finally got my c4 sd connect working and before all this, cleared all the codes. Also tracked down the code I was getting on the AC system. Circulation pump failure on the rear AC. There is a diagnostic procedure I will attempt but one of the steps involved getting to some valve block on the passenger side firewall of the engine bay.

After looking around, I think I know the source of the slow coolant drip. The driver side turbo. The supply line for coolant connects right above the engine mount on the underside of turbo. Will likely have to drop engine carrier again to get to it but hoping my small hands can somehow get up there to avoid the pain of setting up the engine crane and removing the engine carrier.

I feel like the light at the end of the tunnel for mechanically refurbishing this car is within reach 😁

 

NEVER remove/reinstall the radiator fan plug with the battery connected!
Been there, done that. The fan never worked after that, and I had to change it.

 

Didn't realize this. I guess I got lucky the first time I removed and reinstalled it.
Will confirm if I fried the fan later by trying to enable to via diagnostics.

 

please let us know what the problem is , I am having fan issues

 

I also had the same ABC symptoms you were having just yesterday. At a stoplight, two corners would just raise and lower by itself erratically, and the car looked like it was doing some sort of mating ritual dance to onlookers nearby. It stopped as soon as I accelerated away. When coming to the next light, it would start doing it again. I checked fluids and everything else seemed to be normal. No errors on dash.

When I took it out today, it showed no signs of the problem ever occurring. I even washed the car today and still no issues at all. It's weird since this is the first time this happened for me as well.

It probably has nothing to do with your car wash or your fan not working. The abc does weird stuff sometimes but this is coincidentally a first for both me and you.

 

me too

 

Fan is fried. Diagnostic tool couldn't activate it. New aftermarket fan on order for $275. Didn't want to spend $1,200 on a new OE fan....
Now I know to disconnect battery. Expensive lesson. One would think the relay / controller system prevents this.
Was really hoping to use the car for the holidays since I have guests coming into town.

For ABC, I checked the codes and it had the code C1122-002 Fault in component B24/4 (right front body acceleration sensor). I must have gotten it wet and it had a faulty signal during the drive. Car seems to be fine now so I'll leave it alone.

 

Found the coolant leak! As I suspected, it's the turbo coolant line. Luckily it's the one on top and not bottom. The bottom one would require removal of engine mount.

I'm having some trouble getting enough clearance to get the coolant line off since the intercooler hard line is in the way. The bolts holding the intercooler line against the cylinder heads are a real pain since there are so many other things in the way. Need to get the last bolt off at the rear of the cylinder head to get the line completely free.
I wasn't able to find any remnant of the O-ring that belongs there. Anyone know if the O-ring is supposed to wrap around the coolant line end or just sits inside the port on the turbo?




Stop lamp switch also replaced and that only took 15 minutes total.
After the turbo coolant leak is fixed, I only have the intermittent rear AC code to solve.

I'm doing a trip from Los Angels to San Francisco end of this month. Hoping I'll have the car ready for the drive!

 

O-ring wraps around the coolant line and slips into turbo housing. A bit of silicone grease will help with that. I bought a 1/4" drive E10 socket to fit that very bolt. Nothing else worked for me...

 

Thanks! I was able to find the old o-ring. It was so hard that I thought it was part of the line. After some scraping with a pick, I realized it was in a groove on the line. 1/4" E10 socket would have helped, but was able to make it work with 3/8 E10. Used a screw driver to tap the line back into place since there was a flange I was able to get a good contact with.
Car is put back together and working now. I'm sooooo happy it wasn't the o-ring on the supply side line under the turbo.

Used DAS to reset the car after the brake lamp switch replacement. It was acting up with all kinds of ESP and brake light errors. Seems okay now.

Since the car overheated to about 120C at least twice (didn't reach red zone luckily), I went ahead and changed the oil even though it only had ~30 miles. Flushed the coolant system with a few runs of distilled water and did the same on the intercooler system.

Only code that still comes up is the Circulation Pump A31/1m1 (B1426). New pump/valve is about $120 so I may just go ahead and order it to have handy for when I wrench on the car next.