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Last weekend I attempted to change out all 4 cam position sensors and cam magnets, and install the harness-protecting pigtails. I did the position sensors first and that was very straightforward. Lots of oil in the connectors, but I cleaned it out, installed the pigtails, bolted in the new sensors, etc. Not a big deal.
I then moved down to the magnets and that's a very different story. No tools I had could get onto all the bolts for even a single magnet. So I put that job off until this weekend while I waited on an assortment of E10 wrenches that I thought would make the job possible. Today I get to the car and my problems start.
The cam magnet furthest to the passenger side was the easiest to access so I started there. With the new tools, I was able to get it off without removing much if anything else. On reinstallation, I was using a beam type torque wrench to install the new magnet to 8Nm. One of the bolts snapped off at between 4 and 5 Nm. My local dealer said they didn't have any of these bolts (we were both surprised) and that only one dealer (45 minutes away) was the only one in the state that had these bolts. I called them to verify and find out when they close. Yes, they had them, but they closed in 20 minutes. The guy tells me lots of dealers have these bolts, not just them, so I start calling around. Two other dealers 45 minutes away also had them, and one of them closed late enough for me to have a chance to get there on time. Then I had the thought that the nearest dealer might have had the part number wrong so I called them back and sure enough, they had the bolts. Now I just had to wait for a friend to give me a ride. While waiting, I was able to "drift" the broken bolt out of the cam cover with a lot of tiny little taps with a punch. It was actually very easy because it broke at such a low torque. And it was only possible because I was working on the most accessible magnet.
While installing the new magnet, I noticed that the old bolts had anti-seize on them, which was also in the bolt holes. Rather than try to clean this stuff out, I monitored the torque and the feel of the bolts as I tightened them. They all plateaued in torque at between 4 and 5Nm, so I did not go any tighter. I think they were starting to stretch and would have failed if I had gone much more. I think this is 100% because of the anti-seize. Whoever applied the anti-seize may also have fatigued the bolts by trying to set them to the proper torque spec or just torqued them too much by hand.
Check your old bolts for inappropriately applied anti-seize, and consider not re-using aluminum bolts at all!
Moving to the next cam magnet to the right, I am blocked by at least the turbo inlet pipe. I have watched so many videos of people using a long screwdriver to loosen the clamp at the turbo inlet and popping that pipe right off. HOW!? I can't even see more than 1/2" of the clamp, and can't see the bolt on it at all. I'm blocked by all kinds of stuff down there that other people don't seem to have.
Next one to the right is blocked by some oil lines:
Finally, the rightmost one is blocked by the oil filter housing itself. I have seen people do this magnet by only removing the cap to the filter housing, but that is not possible on my car. The metal part of the housing prevents getting even an E10 box wrench onto this bolt and I'm not sure the bolt itself could back all the way out with the housing in place:
To top it all off, at some point in this process, one of the locking tabs on one of the cam magnets snapped off, so I can't get a positive lock on the connector to that magnet without changing the magnet... Now I don't even want to drive the car. What happens if the magnet connector disconnects while the engine is running? Seems to me like that could lead to valves meeting pistons?
A royal pain for sure !
These aluminum bolts are indeed single usage.
The threads are sealed so they don't leak out oil from high blow-by pressure.
You'll want to renew your tensioners. Then you'll have great access to VVT solenoids.
All these unnecessary damages are what normal oiling prevents:
Leaky limp tensioners
Burned sensors "oil-in-harness"
Rattling loose VVT locks
Leaky oil exchanger seals
.... cracked pistons/ dry cylinders
burned black oil at 500Mi
Simple solutions are available
Tensioners are definitely on the list. Biggest two items were to stop the bleeding and save my harness, and fix the stupidest coolant leak I've ever seen.
Using the voodoo from that video, or something similar, I was able to get the second cam magnet (the broken one). I have an idea for the 4th one but I need to make a tool first. Number 3, we'll see...
A royal pain for sure !
These aluminum bolts are indeed single usage.
The threads are sealed so they don't leak out oil from high blow-by pressure.
By the way, I realized that there was a sealant on the bolts, but that isn't what I was referring to when I said there was anti-seize. I'm now not 100% sure it was anti-seize, but the bolts had a shiny, metallic paste on them. The only other possibility would be a mixture of sheared off Al/Mg and oil, which just doesn't seem likely.
By the way, I realized that there was a sealant on the bolts, but that isn't what I was referring to when I said there was anti-seize. I'm now not 100% sure it was anti-seize, but the bolts had a shiny, metallic paste on them. The only other possibility would be a mixture of sheared off Al/Mg and oil, which just doesn't seem likely.
The timing cover torque is like "two fingers tight". We wonder why everything so weak?
The fasteners need to be weaker than the engine heads to preserve threads from stripping.
So the assembly is carefully sealed or glued whatever you want to call this.
Tensioner uses similar short aluminum fasteners. Good luck honestly torquing aluminum.... Loctite + RTV sealant where needed.
I was going to RTV seal the back of my tensioners but thought it would prevent them from positioning well under load with weak fasteners. Instead i sended the rough surface smooth.
So timing covers fasteners are good to practice with.
I understood that these were one-time use because of the factory applied sealant. However, I also have 6 different kinds of loctite and can choose and apply one if necessary. Most people aren't going to leave a car disassembled because they didn't end up getting fresh bolts when they can just add their own threadlocker or sealant. What surprised me was how weak the bolt was going in the second time. Possibly it was more than the second time (that's something to keep in mind with a bolt of any material--you don't know the history of any bolt you didn't install). Reminder that when I was putting in the factory-fresh bolts, the torque peaked at around half of the torque spec. I have a tiny beam type torque wrench that I got for working on things designed by the insane engineers at Porsche so I grabbed that to see the torque value live instead of waiting for the click (of the wrench or the bolt shank--whichever came first). I wasn't going any tighter once the torque plateaued. It's a bit scary to see that on such tiny aluminum fasteners honestly.
Mercedes mentions in that document that the threads may need to be recut if the hole is blind and a "microencapsulated" bolt was used. Why is Mercedes spec'ing thread sealant on fasteners in blind holes?🤔
By the way, in that document, Mercedes says:
"Bolts and nuts that have a polyamide coating (D) can generally be unscrewed without leaving any residue, so that any recutting of the mating thread is not required. Apart from this, bolts and nuts with a polyamide coating (D) can be used several times without the locking function being impaired. In isolated cases it may be specified that bolts and nuts with a polyamide coating (D) must be replaced after having been used once."
I believe these bolts are the type which have the "all-around" polyamide coating.
The original language of Mercedes WIS is German.
I find sometime their English version, the one we use, its description is not too good.
re-cutting simply means CLEANING the thread.
ALU bolts are usually one time use because perhaps MB do not want to risk breaking....but are ALU really weak ? NOPE.
The tranny oil pan is also one time use baby bolts, but you can re-use if only for 2nd time. I done that.
The CAM magnets, I re-use those baby bolts too, when I fixed the true oil leak. Read here : https://mbworld.org/forums/e-class-w...lant-work.html
Cam magnets uses O-ring as the true oil seal, whenever o-ring is used, no need strong force on bolts.
See, CAM magnets removed ( for the 2nd time ) and I did not bother to buy new bolts again.
Clean the thread locker and apply Loctite, all good. Torque as per MB spec.
The original language of Mercedes WIS is German.
I find sometime their English version, the one we use, its description is not too good.
re-cutting simply means CLEANING the thread.
Yeah I understood it to mean cleaning the threads, which I would do with a tap as I'm not sure how else you would do it honestly... So basically it's the same operation as recutting buggered up threads.
Edit: actually, now that I think about it, you would not be able to get a tap into, or any other cleaning tool really. Maybe would be sufficient to cut a "flute" into an old bolt and thread it in and out a few times, then blow.
The large round O-ring is one seal then there are the screws themselves that must be sealed... through holes !!
I have removed/resealed the VVT covers but have not needed to do anything with the "magnets" themselves.
Their 3x screws must be sealed else crankcase pressure will force oil through screw threads.
Last edited by CaliBenzDriver; Nov 22, 2024 at 09:33 PM.
Last weekend I attempted to change out all 4 cam position sensors and cam magnets, and install the harness-protecting pigtails. I did the position sensors first and that was very straightforward. Lots of oil in the connectors, but I cleaned it out, installed the pigtails, bolted in the new sensors, etc. Not a big deal.
I then moved down to the magnets and that's a very different story. No tools I had could get onto all the bolts for even a single magnet. So I put that job off until this weekend while I waited on an assortment of E10 wrenches that I thought would make the job possible. Today I get to the car and my problems start.
The cam magnet furthest to the passenger side was the easiest to access so I started there. With the new tools, I was able to get it off without removing much if anything else. On reinstallation, I was using a beam type torque wrench to install the new magnet to 8Nm. One of the bolts snapped off at between 4 and 5 Nm. My local dealer said they didn't have any of these bolts (we were both surprised) and that only one dealer (45 minutes away) was the only one in the state that had these bolts. I called them to verify and find out when they close. Yes, they had them, but they closed in 20 minutes. The guy tells me lots of dealers have these bolts, not just them, so I start calling around. Two other dealers 45 minutes away also had them, and one of them closed late enough for me to have a chance to get there on time. Then I had the thought that the nearest dealer might have had the part number wrong so I called them back and sure enough, they had the bolts. Now I just had to wait for a friend to give me a ride. While waiting, I was able to "drift" the broken bolt out of the cam cover with a lot of tiny little taps with a punch. It was actually very easy because it broke at such a low torque. And it was only possible because I was working on the most accessible magnet.
While installing the new magnet, I noticed that the old bolts had anti-seize on them, which was also in the bolt holes. Rather than try to clean this stuff out, I monitored the torque and the feel of the bolts as I tightened them. They all plateaued in torque at between 4 and 5Nm, so I did not go any tighter. I think they were starting to stretch and would have failed if I had gone much more. I think this is 100% because of the anti-seize. Whoever applied the anti-seize may also have fatigued the bolts by trying to set them to the proper torque spec or just torqued them too much by hand.
Check your old bolts for inappropriately applied anti-seize, and consider not re-using aluminum bolts at all!
Moving to the next cam magnet to the right, I am blocked by at least the turbo inlet pipe. I have watched so many videos of people using a long screwdriver to loosen the clamp at the turbo inlet and popping that pipe right off. HOW!? I can't even see more than 1/2" of the clamp, and can't see the bolt on it at all. I'm blocked by all kinds of stuff down there that other people don't seem to have.
Next one to the right is blocked by some oil lines:
Finally, the rightmost one is blocked by the oil filter housing itself. I have seen people do this magnet by only removing the cap to the filter housing, but that is not possible on my car. The metal part of the housing prevents getting even an E10 box wrench onto this bolt and I'm not sure the bolt itself could back all the way out with the housing in place:
To top it all off, at some point in this process, one of the locking tabs on one of the cam magnets snapped off, so I can't get a positive lock on the connector to that magnet without changing the magnet... Now I don't even want to drive the car. What happens if the magnet connector disconnects while the engine is running? Seems to me like that could lead to valves meeting pistons?
If these M6 screws are made of aluminum the 8Nm torque sounds a bit high for me.
The recommended regular steel bolt (8.8) torque is around 12Nm but this is 4-5 times stronger material than aluminum.
No wonder your torque platoed around 4-5Nm as you already almost broke them.
For the record, I don't know where I got the torque spec (probably another forum post with spotty info), but I just pulled up the relevant spot in the WIS and the correct torque value given there is 4Nm. I'm not sure where I got 8 from, but I assure you it wasn't my butt, even if the effect was equivalent.
For the record, I don't know where I got the torque spec (probably another forum post with spotty info), but I just pulled up the relevant spot in the WIS and the correct torque value given there is 4Nm. I'm not sure where I got 8 from, but I assure you it wasn't my butt, even if the effect was equivalent.
I found it in a bunch of parts of the WIS--usually with blank values... Now I need to go back and find it again to see if the page I was on had an angle...
There was a time, long time ago, I forgot the actual reason............
My WIS has missing alphabets, see below :
My WIS 2020 is downloaded from somewhere, which I forgot where from.
It often can not be accessed due to corrupted KEY or whatever they call it.
This is different from the missing alphabets issue.
My EPC is knock off from Ebay, 2018 version. It can not produce Data Card.
None of my WIS or EPC can output PDF, both will output the dumb-azz XPS of microsoft.
All above is on my PC, where I like working on because it has 27" x 2 screens. I can't work on laptop even 17" ones, too small and single screen I hate it.
----------------
My Benz-Ninja EPC and WIS version is the best, it can produce data card and can produce PDF. But it is on a laptop, so me don't use it for EPC/WIS work, only Xentry.
The "blank" values were actually filled in by someone/a computer with "-"... I need to figure out the logic to finding the right thing in WIS instead of mindlessly clicking through all the wrong documents first.
Does the BenzNinja laptop have any kind of video out connection? Must be really old and use a VGA port or something, right?
4Nm and 60 degrees, probably that will be 8Nm...maybe
If it is aluminum screws it sounds high for me, but perhaps MB has some extra special strong alllwy they use.
I personally just snug them screws up with common sense. If thread sealant/locking is used the screws do not need to be very tight at all. Sensor has O-ring seal on it.
I found when measuring the torque live while putting the screws in the second time that the torque peaks at 4Nm. You might be able to get 60 degrees while staying at 4Nm without the bolt snapping, but F that...
The first bolt broke because I re-used it. It didn't plateau, rotate, and then snap, it just snapped right about when the torque got to 4Nm. It was probably stretched to near its limit the first time it was put in...
where from.
