Also, just based on my own experience and since you said you had two misfires on the same side; sometimes the valve cover gasket on the misfire side leaks oil into the well of the spark plug causing the misfire. So if and when you pull off the coil pack on the misfire side, check for oil seepage.
Finally, re-read or search the posts on misfire especially the issues associated with the Y Pipe intake leak. This also happened to me. As the engine was put under load, a small crack between the Y Pipe and the adjustable clamp caused a vacuum leak popping a P0300 code. Tightening the clamp only worked for awhile since my Y Pipe actually had a hairline crack in it at the base (probably caused by some clown over tightening the clamp). Replaced the Y Pipe and code ceased.
Thanks for noting that as well. I did read those issues too so I think the best way for this to be tackled is for me to do it myself (vs. a mechanic), otherwise it'll be way too much money and potentially missing some of these potential failure points. I will keep the team posted on which route I go, so other searchers can follow along if they run into the same issue. Thanks for your help!
Also, just based on my own experience and since you said you had two misfires on the same side; sometimes the valve cover gasket on the misfire side leaks oil into the well of the spark plug causing the misfire. So if and when you pull off the coil pack on the misfire side, check for oil seepage.
Finally, re-read or search the posts on misfire especially the issues associated with the Y Pipe intake leak. This also happened to me. As the engine was put under load, a small crack between the Y Pipe and the adjustable clamp caused a vacuum leak popping a P0300 code. Tightening the clamp only worked for awhile since my Y Pipe actually had a hairline crack in it at the base (probably caused by some clown over tightening the clamp). Replaced the Y Pipe and code ceased.
Pulled these coils out this weekend and found oil seepage on the driver's side, where the misfire is on two cylinders. I noticed most of the screws just weren't very tight.
a) Does this mean the misfires could be caused from the oil alone and I shouldn't replace the coils but rather just the valve gaskets?
b) Is there a good procedure or video somewhere for the valve gasket replacements? Clark's is just for naturally aspirated vehicles.
c) What's the best method to clean the oil from the spark plug wells before I remove the plugs?
Thank you for all your help! I'm following all your advice and currently was planning to re-build both coil packs with Clark and replace plugs and the Boost Box, as well.
valve cover gaskets hide just the valves and the rockers on old fashioned, inefficient engines from the 1950s
cam cover gaskets give access to the 1970s overhead cam design and the valves...
but then in a penny pinching nasty mess up Merc often built the cam bearing caps into the cam cover and its a nightmare - I think the v12 is normal the v8 is a disaster of cracked cam carriers super glued in place by sadistic engine bodgers
que jacking the car up by the unbolted cam covers for 48 hours with a hair dryer and praying a lot
valve cover gaskets hide just the valves and the rockers on old fashioned, inefficient engines from the 1950s
cam cover gaskets give access to the 1970s overhead cam design and the valves...
but then in a penny pinching nasty mess up Merc often built the cam bearing caps into the cam cover and its a nightmare - I think the v12 is normal the v8 is a disaster of cracked cam carriers super glued in place by sadistic engine bodgers
que jacking the car up by the unbolted cam covers for 48 hours with a hair dryer and praying a lot
I'm so confused. Is there another repair that I need to make besides my valve cover gasket replacement, then? I was under the impression from Clark and forum's guidance that coil packs, VT box, plugs, and valve cover gaskets should get my vehicle back to top shape.
Quote: I'm so confused. Is there another repair that I need to make besides my valve cover gasket replacement, then? I was under the impression from Clark and forum's guidance that coil packs, VT box, plugs, and valve cover gaskets should get my vehicle back to top shape.
you do not have ANY valve cover gaskets - I don’t think any Merc has had them since the 1960s - OK they did make a Tractor engine with OHV in 1983 and a few afterwards
... on the V12 a number of things can misbehave in relation to misfires and costs are quite incredible in general upkeep
many break a line or connector at the back of the engine playing with the ignition coil pack replacement - I forget what it brings oil, engine vacuum, or coolant leak
the charge intercooler is often empty - from leaks. The metal coolant pipes often rust through and dumps it, this can lead to coolant around the plug area
(it has a water cooled inlet air cooling system - because turbos make air hot - this brings it down from 350C to about 90C)
the nine million spark plugs need changing to schedule
the coil packs self disintegrate
the VT overheats and takes out coil packs
the cam cover gaskets weep and make a mess and people notice when the ignition faults arrive - it shouldn't do any harm but if you like working....
naming convention issues arise where some parts of the world went their own way and made up names AND manufactures like to make the world complex and confusing by using random inaccurate naming too
Merc on the V12 call the cam covers, "cylinder covers" and the cam chest gasket in the middle of the Vee (that Americans like to call the valley cover) a cam cover
Are cam cover gaskets different than valve cover gaskets?
Same junk. Botus is his usual salty British self. Read his words with the song played at the end of ‘Monty Python’ shows where they are all chasing each other in your head. Then his prose may start to make some sense. I suspect many of his posts happen after having partaken half a dozen or more pints of the warm beer the Brits are fond of. Lucas refrigeration and all.
Pulled these coils out this weekend and found oil seepage on the driver's side, where the misfire is on two cylinders. I noticed most of the screws just weren't very tight.
a) Does this mean the misfires could be caused from the oil alone and I shouldn't replace the coils but rather just the valve gaskets?
b) Is there a good procedure or video somewhere for the valve gasket replacements? Clark's is just for naturally aspirated vehicles.
c) What's the best method to clean the oil from the spark plug wells before I remove the plugs?
Thank you for all your help! I'm following all your advice and currently was planning to re-build both coil packs with Clark and replace plugs and the Boost Box, as well.
All I can do is advise you based on my experience with my 2007 S600 V12 TT. I had oil seepage in two X 2 of my spark plugs on one side. Constant misfires. I replaced the gaskets on both sides, replaced the plugs on both sides (24 of them at $10 each), replaced the coil packs on both sides, and replaced the Voltage Transformer (all with Clark's parts). Misfires ceased. Car runs smooth as a baby's butt. Very happy. Then put the car on a decent maintenance schedule for oil changes, air filter changes, and keep an eye out for vacuum leaks especially at the Y Pipe junction. Report back your results here. Good luck.
Same junk. Botus is his usual salty British self. Read his words with the song played at the end of ‘Monty Python’ shows where they are all chasing each other in your head. Then his prose may start to make some sense. I suspect many of his posts happen after having partaken half a dozen or more pints of the warm beer the Brits are fond of. Lucas refrigeration and all.
I've made you some pictures to help with your English lessons - the name directly next to the part number is Mercedes Benz's version of events, the Red Font is English
All I can do is advise you based on my experience with my 2007 S600 V12 TT. I had oil seepage in two X 2 of my spark plugs on one side. Constant misfires. I replaced the gaskets on both sides, replaced the plugs on both sides (24 of them at $10 each), replaced the coil packs on both sides, and replaced the Voltage Transformer (all with Clark's parts). Misfires ceased. Car runs smooth as a baby's butt. Very happy. Then put the car on a decent maintenance schedule for oil changes, air filter changes, and keep an eye out for vacuum leaks especially at the Y Pipe junction. Report back your results here. Good luck.
Trying to get these valve covers off but I don't see how I do it with the charge intercoolers still on. The coolant lines back there are in the way and I cannot lift the valve covers off in the back to remove them without seemingly disconnecting those coolant lines.
Did you have to remove these to get the valve covers off?
If I drain the system of coolant so I can take these off, what is the proper way to refill so I don't get air pockets? I have the system open (at least I thought so) up top and rotating the radiator drain at the bottom isn't draining any coolant.
Charge coolers will have to come out. Be gentle. The hoses don’t want to just let go of the aluminum pipes on charge coolers.
Once it is all re-assembled run the engine long enough to know valve covers are not leaking.... Install charge coolers. Put the charge cooling circuit in a vacuum and fill it via a hose into a bottle of coolant. (Buy the tools... will come in handy.) This will help with most of the pain that is bleeding charge cooling. There are bleeders on the charge coolers. Use them to burp air out once the system is up to temperature so it will have some pressure in it.
XENTRY will let you turn the charge cooling pump on to verify operation.
Charge coolers will have to come out. Be gentle. The hoses don’t want to just let go of the aluminum pipes on charge coolers.
Once it is all re-assembled run the engine long enough to know valve covers are not leaking.... Install charge coolers. Put the charge cooling circuit in a vacuum and fill it via a hose into a bottle of coolant. (Buy the tools... will come in handy.) This will help with most of the pain that is bleeding charge cooling. There are bleeders on the charge coolers. Use them to burp air out once the system is up to temperature so it will have some pressure in it.
XENTRY will let you turn the charge cooling pump on to verify operation.
Couple questions so I can keep up:
a) If I run the engine without the charge coolers connected and properly charged with coolant, wouldn't that run that the cooling pump dry and ruin that pump while I'm checking my valve covers for leaks?
b) I don't have the tools OR XENTRY to burp this system. I can buy and craft a tool to do this, but without access to XENTRY, am I dead in the water for doing this at home?
c) If I simply top off the charge cooler circuit (without burping it) could it be driven to a local shop to do the proper burping procedure, or must it be towed?
when doing the pipes check their condition - quite a few are rotted out
Thanks BOTUS. Does that mean I can run the vehicle with that circuit dry, without causing damage? My hoses seem fine back there and i had plenty of fluid in them.
I have never seen answers on this forum - but it goes back many years so there might be
I would aim to fill as best you can and try and bleed - I always find it odd you can pull a vacuum on rubber hoses and magically fill the system the way you see on videos - it must help but I think there's an element of BS in the mix
the pump design appears to be electric so you could disconnect - as you first play - remember the intercooler is designed to cool vast quantities of air that's getting stupidly hot under max boost - so idling its doing next to nothing
pipes are non flexible tubes for gas or liquids
hoses are flexible versions
the pipes do fail there was one this year.... system empty lots of fun dealer made stuff worse then argues he didn't
decent diagnostics to at least see what issues the car is complaining about and clear engine related stuff is essential for driving any modern vehicle - as a min I would have
you can buy junk for $20 on the internerd - but you'll end up with 4, will have spend $10 more and have half the capability of a decent one (only giving that link as they at least mention what they are)
Botus your not having used vacuum in a cooling system doesn’t change how effective it is in removing air from everything in a cooling circuit so that it can be filled by using that vacuum to suck coolant from a bottle to fill it.
OP if you are not willing/able to invest in proper tools; unplug the charge cooling pump.... down low on passenger side aft of smaller heat exchanger on pax side. Have a pro fill/bleed with vacuum. Keep it out of boost when driving to the shop who will do it.
Yes; the engine can be run without charge air coolers in place. Just be sure nothing gets in turbos as it idles so you can verify no leaks after replacement of gaskets.
To anyone following my repair here, I ended up replacing spark plugs, coils, valve gaskets, and the voltage converter with a boost box, all from Clark Rupp at www.v12icpack.com, using the top procedure below as a guide. Clark gave good pre and post-sale support, answering any questions I had, so I fully endorse purchasing from him. He's professionally organized and my car runs like a scared rabbit, now.
Given that I had to take the charge coolers off to replace my valve cover gaskets, I had to drain and refill that coolant circuit (which is separate from the main engine block cooling circuit). I bought a Topdon ArtDiag900 bidirectional scan tool that allowed me to drive the car's coolant circulating pump using the bottom procedure below, which starts around the 27 minute mark of the video. I found this much easier than the complex vacuum setups people were using. I used the Pittsburgh Coolant Filling system from Harbor Freight that he recommended in the video, as the one I bought from OEMTools leaked.
Also note that as we discussed here, if you have a 2007 S65 like me and your valve covers are leaking, I really don't see how you get them off WITHOUT removing the charge coolers as I had to do, so just drain that system like I did and save yourself some headaches. Be CAREFUL with the charge coolers, as they're thin and the metal can bend easily around the male barb connections that accept the coolant hoses. I took mine out-of-round by gripping the hoses too hard with channel locks as I tried to separate the hoses from the male barbs, so don't do what I did. Simply grip them lightly and ROTATE the hoses on the male barb that will release the rubber hose from the barb which is being held on by stiction and it can be pulled off after that.
There was no way I could document what I did because I re-did so many steps and learned along the way. The above procedure from Clark is pretty solid if you aren't getting into the valve covers. If you're going into the valve covers, it sounds simple to remove 14 screws to get the covers off, but removing the crap around them in a bay this tight posed more challenges than getting all the way to the spark plugs, honestly. But, if I can do this, so can any other with decent tools and general knowledge around a vehicle.
The work I did on my vehicle during this repair cost me about $~2900 but if I would have had Mercedes do all of this and bought their parts (with arguably worse durability than Clark's), I expect I would have paid over $8000. Do this yourself at home if you can.
Pulled these coils out this weekend and found oil seepage on the driver's side, where the misfire is on two cylinders. I noticed most of the screws just weren't very tight.
a) Does this mean the misfires could be caused from the oil alone and I shouldn't replace the coils but rather just the valve gaskets?
b) Is there a good procedure or video somewhere for the valve gasket replacements? Clark's is just for naturally aspirated vehicles.
c) What's the best method to clean the oil from the spark plug wells before I remove the plugs?
Thank you for all your help! I'm following all your advice and currently was planning to re-build both coil packs with Clark and replace plugs and the Boost Box, as well.
I had the same oil leakage into to spark plug wells on my 2009 S600 V-12. It’s been mentioned in the forums oil down in the spark plug wells can cause arcing.
Also 78,000mi and 16 year old coil packs can be root cause as well.
All of the bolts on the valve covers were very loose. The torque spec from the forum is 4Nm, just beyond hand tight. I removed all spark plugs and was prepared with new iridium plugs gapped by me. Just replace them while your in there to rule out plugs as a cause. The oil could have caused arcing, thermal issues on the spark plug ceramic insulator, micro fractures.
Clark reminded me to never power wash this V12 engine, as water mixed with garbage will get down in the spark plug wells and the arcing begins.
I wrapped a nylon/cotton (won’t leave any hairs to cause a leak) clean rag around a 1/4” extension, and rotated it CCW, replacing rag often, until all spark plugs wells were clean.
Installed my new iridium double checked gapped plugs and torqued them to spec with a torque wrench. Aluminum heads, be exact.
Wiped up the oil on side of motor and torque the bolts on the valve cover to 4Nm with a torque wrench.
I didn’t have time to wait for new gaskets for cover. To date, no oil has dripped out as I occasionally verify torque.
I learned to tape every open orifice while working on this car. I thought a dropped bolt fell into the open pipe to the top of the turbo. The only way to move forward was to remove the turbo and dump out the bolt. While waiting for my friend to arrive with a fiber optic scope, I pulled the belly pan and out fell the bolt. What a relief!
I immediately taped ever open orifice with brightly colored tape .
If your first time with the coil pack cassettes, do not rock them more than 1/4” like Clark explains in the video.
I damaged one taking it out for troubleshooting and fractured the multi layer circuit board. Coupe de Grau! Sorry kid, not covered under warranty.
You’ll notice the tubes are slightly loose like a loose tooth. This allows for a little give when installing and removing. Try not to force anything or tilt it too much in the install or removal as Clark will want your old ones for repair or referb.
I did apply a very thin coat of dielectric grease on the inside of the very tip of the red rubber insulators per FCP via Mercedes recommendation, and the coil pack inserted very smoothly.
Clarks stuff is very good quality, operational quality checked, and nice price. I happened to damage one of them by tilting it extremely, cracking the circuit board. Warranty didn’t apply in this case.
My daily driver, didn’t have the time to wait for repair from Clark, so I had to buy in from FCP Euro at twice the price.
I would suggest to go with Clark’s stuff and try not to screw it up!
@johnnyrocket52 I wonder if you have the torque specs wrong. See my attachment. 4Nm is the first stage of tightening and then I read that you go an extra 120 degrees from that, which I measured to be about 13Nm on my torque wrench!
I didn't initially know which engine I had so I just tightened mine down to 10Nm but I think I'm going to go back in and quickly tighten them up just a little more per the spec there. If anyone sees that I'm reading this wrong, please let me know.
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
