M275 Engine Oil Cooler Type, Location, is it rebuildable
 

Hi Everyone.

I bought a CL600 2003 w the Twin Turbo M275 engine 102K. miles. Does the M275 engine have the internal oil cooler like the pre turbo cars? It looks like they went with an external oil cooler on the M275 therefore the monster job of doing and R&R on it is moot. I can't seem to find that info anywhere. Also if I am on the hook for the internal oil cooler job are they still not serviceable? It seems what goes bad are the gaskets and the aluminum is fine. I have searched for hours so please don't spank me for that. This is the most important question.

Other items I have replaced:

I have replaced both coil packs with Clarks v12icpack units. The cars idle is impossibly smooth. Also R&R all 4 of the accumulators in the ABC circuit. Trans mount and (2) flex disks. All fluids and conductor plate R&R. I have access to lifts and techs in my business. In order to save time and $ I took the car to a dealer and they said I need the oil cooler, both front struts are leaking and some misc items. The service advisor said my engine is leaking oil and the cooler is the problem. 30 hours labor and engine has to Come out etc. Intercooler pump may be bad and the car will need an intercooler prime as the IAT are high.

My searching has revealed that the intercooler pump fails and causes a loss of power. Dealer says a vacuum leak will also cause the same.

Any and all help is greatly appreciated.

Don't worry, the V12TT doesn't have the internal cooler. It uses an air to oil cooler in front of the radiator at the bottom. It's straightforward to access.
The intercooler system always causes problems. You can test the pump by jumping the relay, but air in the system often causes problems and is very difficult to get out. There are lots of threads on the subject. If the pump is still OK, my advice is to grab the bull by the horns and use a vacuum refiller plus a rotary vane vacuum pump.
Leaks from the suspension struts themselves are rare. You should see it for yourself first. It sounds like you have been misled somewhat.
Nick

Just to chime in, the dealer might be half-way right (but not exactly) on the oil leak. Just like Welwynnick said, the 2003 and newer cars (twin turbos) do not have an oil cooler between the v of the block, it is external. However, the center valley cover between the cylinder heads does leak over time. At the rear of this cover is the supply line for oil to the turbos. There is an internal o ring for that supply line under the center cover that leaks causing oil to fill the rear reservoir of the block. This reservoir does not have adequate drainage for that much oil which then causes a leak out that top cover in the rear. (hope that makes sense).

If that center cover is leaking, then yes the dealer is right on the effort required to change the seal. Cylinder heads need to be removed (cover is underneath) which means engine needs to come out. Depending on the severity of the leak, I would say not worth the fix and just drive with the oil leak. Obviously, the fact that the oil supply line for the turbos is leaking doesn't bode well for oil pressure to the turbos but the only fix is engine out and means big expense time if your not doing your own work. But as far as m275 goes, I would bet that all v12 TT of our era cars have some form of an oil leak at that rear cover from age and mileage. You can look at engines for sale even with lower mileage and you will see oil grime at the rear of that cover. So again, if the leak is not terrible then best leave alone for now.

I know all this because I changed this cover on my car as mine was also leaking. I had the engine out for other reasons so it was my excuse to do at that time. I took the time to analyze why it happened and unfortunately 1 little $2 o ring is the cause of this mess.

Here is a picture to give you better idea:
The front (left side) of the cover manages the coolant valley and the back (right side) manages that rear reservoir that for our car should not have oil in it. The o ring is meant to seal the flow of oil up and out of the valley to the turbo oil supply lines. The rear reservoir was originally designed for the PCV system on the m137.
https://cimg4.ibsrv.net/gimg/www.mbw...b203cddd6f.jpg

The small o ring under item 370 and the large part of 370 are the culprits.

Wow! I just can't thank you enough. I did hit the thanks button for you guys and wish I could do it a few hundred times. Even if the news was bitter sweet. The leak to me isn't that severe. I don't see engine oil in the pan in quantities that cause concern. The struts do leak quite a bit. Enough to leave a few drops while stopped for a few hours.

This car has been a dream of mine to own since I saw it many years ago. Just so beautiful and I am super happy to have it in my garage, even with the issues. I think once I get it to my facility I'll take the challenge to drop the engine and refresh everything I can. The suspension work, as well as the coils weren't that hard. Much easier than people make it sound. I did buy a Star MB laptop from the usual suspects. Can't wait to feel the full power with the intercoolers working the way they should.

Does anyone sell the special tools needed to secure the cams in place etc. like AGA Or detailed instructions for sale? Perhaps a forum sponsor?

Thanks again guys.

Glad to help in any way possible. If you have the time and can do the work yourself, it is a much better idea to properly prepare for the job and use the opportunity to replace all the usual suspects that are wear parts on the car and those that require engine out or major surgery otherwise. Good examples of this are to replace all seals and o rings for the oil lines and coolant lines in and out of the turbos and could even throw in chain guides etc depending on mileage. As you probably guess, once the engine is out, it easy to replace these things and all can be done at the same time. This approach will maximize the life of the engine for sure.

One suggestion if you do not already know about it is get a subscription to EPC at https://epc.startekinfo.com/ This is the actual official mercedes EPC Electronic Parts Catalogue updated just like dealers use. Makes ordering parts a breeze. I even use it to organize bolts as it shows exploded diagrams with bolt size and lengths for each bolt hole (very helpful).

For cams, search for M275 M137 timing tool and you can find aftermarket companies selling the set (comes as 3 parts). Our m275 only uses 2 out of the set. The 3rd is for m137.
If you bought the STAR Xentry you should have WIS included with it which will provide all instructions including torques and procedures etc.

Keeps getting better. No I didn't know about the EPC and was wondering if such a thing existed, so thank you very much! I got the flea bay Star and C4 so not sure if I get the WIS. I traded the laptop for work and will be getting another system soon.

Anything in particular I should look for at the struts? They look new on the top to me. May the last installer not tightened something? I'm in the process of moving so all my tools are packed. Back win action in about two weeks.

Update. I changed the intercooler and got the intercooler bleed done at the dealer. Didn't have time make the bleeder. The difference in the car is incredible. What a blast to drive on the highway! So so smooth the speed is deceiving. 70-120 effortlessly and just begs to get me in trouble. Thats the good news. The less good news is that the oil leak is worse now. I have a white abc light on from the previous owners lowering links that are throwing off the ride height parameters. That white abc light won't let me check the oil via the menu since it comes on immediately after I start the car. I'll see about dropping the engine as soon as possible and try to document that. I bought the car knowing it would have issues.Wanted a project and man did I get it :)

If the struts are leaking fluid and they have been replaced recently what would have both of them leaking?

Using the "secret menu" in the instrument, you can view the exact number of quarts. You can look up how to access that menu in the archives of the forum.
In any case, if the oil was low, the car would also have a warning to add a quart or even 2 quarts so you are probably ok for now.

As far as the oil leak, you could inspect further to make sure the oil line that goes to the turbos is not the culprit (or an additional leak). Its under backside of the intake manifold and feeds through a metal line to the top of the turbo. There are gaskets between the center cover and the lines.

Update. I've learned quite a bit in the last few months. R&R both front struts. Car ride height adjusted. No white abc light anymore. I feel the car still doesn't have the power it should. Not that it isn't fast but for 600lbs of torque factory and supposedly Brabus tuned I'm not feeling it. Thats not the main thing. Among the initial items I had done to the car was a replacement conductor plate. The car had some odd transmission habits so I just went ahead and got that done. Initially the car was shifting perfectly, a major improvement after the work was done. The usual suspects of plug, filter, seal and fluid all done. For some reason its periodically leaking trans fluid. The car went into limp mode a few days ago. It "fixed itself" on my way to get some trans oil to and see if it was low. The remnant issue now is its slow to engage in reverse when I need to do so.

It also "clunks" like loose trans mount although a brand new Miele Heavy Duty mount was put in and the engine mounts look perfect. The only part not replaced was the center bearing. Both flex disks and trans mount done.

The car now has 110K miles on it. What underbody parts should I want to replace to make the car ride like factory and not rattle when I hit bumps? Fortunately I have a full shop to help me with this work.

Usually the strut mounts are bad by this point, that's the rattle over bumps. Mine does it anyway. Not serviceable separate, requires complete struts.

You can fill the gap but it doesn't replace the collapsed rubber of the original mount. Band-aid fix but yes, better than worn mounts.

Agreed on repair. If you understand the way that the strut mount works, you will see that washers on top (rubber) only stops the strut from bouncing in the mount and does not change the harsh ride caused by collapsed mount. You can swap used mounts on or if they are not collapsed yet, could fill with urethane to stop the collapse from occuring in the first place. I am actually working on getting some pieces made to be installed inside the mount to keep it from collapsing and keep some of the isolation of the original.

The problem with washers on top-the center point that the top of the strut sits on is metal with very very thin rubber acting as more a isolation from metal to metal contact. When the mount collapses, this metal ring sits on the metal top of the mount. When this happens, you see the top of the strut and the washer sitting above the baseplate. At that point, there is actually no mount isolation anymore and you are running a solid strut mount. So the washer cannot solve this. I took a mount apart that had collapsed and there is no way to repair it once it collapses, you need a good used mount to work from.

Once I get something made, I can post it in case anyone else needs it.

For those who don't like the rubber washer-on-top solution, can I ask if you have tried it?

I think part of the secret of the W220 ride is that the strut top bushes bear the weight of the car (not just the dampers) and are relatively long and soft, so work in conjunction with, and add to the springing. They have little effect at low frequencies, but tend to by-pass the damper at high frequencies, a bit like the tire does, which I think helps to explain why it rides (mostly) comfortably on silly wheels and tires.

However, the downside is that the deep, heavily loaded strut bush is prone to settling in old age, and that means the bush goes slack in some circumstances. The top bush is thin and the bottom bush is thick, so it only takes a small relative settling of the latter to cause the upper bush to lose compression. When you tighten it back up you still have a lot of the lower bush left. No, it's not like new, but it's close.

Of course the real answer would be for MB to sell new bushes, but I dont' think they do. Shame. In the meantime I've been replacing all the bushes on all my cars for several years now, and it's a big win with no downsides and it's virtually for free. A W220 with slack bushes is horrible on bad roads.

Nick

Thanks guys.
 

Hey Nick,

Using washer would work as a good temp solution so long as the bushing isn't fully collapsed. On my struts, the bushing was fully collapsed so there was no more gap in the center and therefore the car was riding with no bushing. At that point, using a washer at the top only stops the bushing from having play but cannot solve the collapsed issue.

Totally agree that the washer can work if the bushing is only partly collapsed and can provide better ride due to lack of play and is super cheap. I have toyed with idea of filling bushings with urethane to stop the collapse before it starts but have not tried it yet.

Best,

in my experience, lowering the w215 ABC suspension shouldn't trigger any ABC codes?

It was really just way too low. Totally out of the range on the star system. Previous owner had put in "Extreme" lowering links. All I know is when we set the links to factory dimensions the light went off. I also changed the front struts so that could have been the cause of the light. I need to rebuild the valve body and I'm done with that for now. The car runs like a beast now. The tie rods and upper control arms need to be R&R.

BTW the car smells like it doesn't have a cat. I changed the CO2 sensor and that fixed the CEL. Only did one side as the Star said it was the right side. Easy job.

Totally. I meant the plastic inside. The door trim cloth delam, the rear ac vent trim, just stuff that baked outside.
https://cimg0.ibsrv.net/gimg/www.mbw...7e5050dc67.png
Do you need a better image? This was the last time I took a pic of the engine cover it was raining a little.
https://cimg5.ibsrv.net/gimg/www.mbw...40c61e51f0.jpg

Thats the only Brabus emblem. It had something on the back lid that looked goofy so I took it off. I'm on my way to de-badge the whole car. I really don't care if it's a Brabus or not. Having said that it would be great to be able to do a VIN search and now for sure. It has an AMG body package and the big yellow Brembo brakes. The previous owner told me the original owner "took the car to Brabus" and spent 50K on it in 2003. Thats all I have to go on.

Yesterday I got an abs light and the steering effort increased. fk. This car is just non-stop. I read it might be a wheel speed sensor. It's intermittent.

Love it