Originally Posted by Welwynnick

https://mbworld.org/forums/m275-v12-...ml#post6242174

I'm convinced that many problems associated with the V12TT can be attributed to high under hood temps caused by the turbos. I never thought of adding turbo blankets though. I'm rather ignorant there unfortunately. I've seen lots of tuning shops sell them, and I appreciate the upsides, but I don't know about the downsides.



Presumably, by insulating the turbo, they increase its operating temperature. I guess that many people have done just that, and I'd sure like to know if they'd had faster turo failures as a consequence. Or not. Our turbos are water-cooled , so I'm sure that helps to protect them. I rebuilt my turbos this summer, and I looked at lots of ways of improving the under-hood heat management:

• I fabricated a couple of heat shields to cover the whole length of the coil packs, sitting just outboard of the existing heat shields. I stuck some temperature tape on the coil packs to see if that lowered their peak surface temps. The results aren't in yet.
• I also wrapped the charge cooler lines in foil and fibreglass heat mats, to help insulate them from the turbos and reduce heat soak. I did the same to the IC's themselves, though I doubt that makes much difference.
• I can monitor my IC coolant temperature from my pump controller, and it does stay cool. I turned down the target temperature from 30C to 25C yesterday, and sure enough it ran 5C cooler today.
• The other thing I've done is replace all the ABC hoses in the engine compartment with compression-jointed removable hoses, and add reflective thermal insulation to those as well. I think that long term, that will probably be the biggest win.
• I did consider adding metal plates to the underside of the pipes between the compressors and the IC's, but I couldn't afford the time
• Of course, adding insulation to the turbos themselves may tackle the root cause of the problem, as long as the turbos themselves don't get too hot.

Nick


There are lots of different ways to do thermal management under hood, and they need to make sure the protection measure addresses the right threat to performance and reliability:

• infra-red radiation
• thermal conduction
• thermal convection

You have to consider both where the heat is coming from, and where it goes to. For example, I think the IC's problem is simply conduction from the surrounding hot air. Yes, they do cool themselves due to the circulating water, but we simply want to reduce the flow of incoming heat. Insulation or lagging should do that. I've got some pictures of what I've done, and I'll post them today.

The coil packs on the other hand, are a rather different problem. They're in line of sight of the turbos, so they're subject to infra-red radiation, and they DON'T cool themselves. Mercedes solution is to screw insulating covers to the exposed center sections. The insulation does have a reflective outer layer, but there's insulation in between, and they're in contact with the coil pack.

I don't think this is a good idea, as there's no air under the shield, and heat will conduct through to the coil. When manufacturers insulate exhaust systems, they normally use single skin metal shields that provide a barrier for IR radiation and convecting air. They provide no insulation at all, but they're very effective. The key thing is that air is able to flow past both sides of the shield, so temps are never allowed to build up.

I think that's what's needed for the coil packs, so I built a pair of ally shields that stand off the coil, allowing air to flow down both sides. It took a few goes, and mounting them is tricky, as there's not much room, but it help if the stock shield is removed. I fitted one, and left the other off, to see what difference they make. I put temperature tape on the coil packs, and I'll take the intakes back off soon & look for any difference between them. What I did notice on Sunday is that on my first long journey for nine months, it never misfired and threw a CEL. Even with both new coil packs, that's still unusual on a long run.

I did similar things to the ABC pipes, and I've got lots of pictures of all these things...

Nick

I removed all the ABC pipes around the engine, and replaced them with new pipes with compression connections:



Taking a closer look at the pipes that were already protected by reflective insulating sleeves. I cleaned the sleeves, but the pipes are as they came off the car. They're in very good condition:



However, the feed pipe from the pump to the regulator wasn't protected, and looks horrible. Draw your own conclusions.



Therefore I protected all the new ones with firesleeve. This is 30mm ID, which is too large. 25mm is ideal.



If I was ever mad enough to buy another car with ABC, I would do all that straight away as a matter course, regardless of the condition of the pipes.

Fitting those pipes can be difficult. What I did was support the engine, undo the engine mounts and drop the front of the subframe.

In this picture you can see how easy it is to access the pipes, the PAS output connection, the diverter valves, and even the ABC output banjo - that's SO difficult otherwise.



Nick

Originally Posted by Welwynnick

https://mbworld.org/forums/s-class-w...ml#post5480311

Hello Nick and Howard,

I'm familiar with the pulsation damper hose which burst on your car.
From the capped end it runs toward the passenger side horizontally, then appears to turn rearward just as it goes past the crankshaft pulley. However it actually does a U-turn there and goes back toward the driver side, then up to the ABC pump. The high pressure output of the pump is a banjo bolt on the underside of the pump and there are two banjos stacked, through which passes the single banjo bolt. The end of your popped hose is the lower of the two stacked banjos.

I cannot warrant the following, but when I examined the routing during a recent ABC pump replacement on my 2004 S600 TT, it appeared to me that I would be able to replace this hose without raising the engine at all, the most difficult part being the tight ratchet access to the banjo bolt from under the front side of the pump, just as had to be done during the pump replacement.

BTW, for anyone contemplating pump replacement, I can offer two very helpful tips in hindsight.
First, for the banjo bolt, use a 3/8" ratchet which has extra fine teeth in the ratcheting mechanism i.e. small angle between clicks, and with minimum backlash. This seemed even more essential for the reassembly compared to the dis-assembly. Secondly for the 10mm e-torx bolt which fastens the pump from the rear side, it may be easier to turn with an e-torx box end wrench having a vertical offset, i.e. an S-shaped bend in the shank near the box end, as viewed from the side of the wrench. I didn't have one, so I had to use a 10mm e-torx socket clamped in vise grips to get the offset, and turning and re-clamping the socket 1/12 revolution each time. None of my 3/8" ratchets would fit into the available space.

Should you find the part number for this pulsation damper hose, kindly post it here because I would like to get one to have on hand.

Good luck,

Drew

Originally Posted by 90sMercs

Dear Nick, Thank you for your fantastic ABC thread which I have read in detail but I am still a bit unsure which pipe has blown and so is the MB dealer! They said the car is "old and rare" which means they can't identify the exact part. They did a video and it runs down from the UK passenger side pump to a joint with a pipe that runs up over the gearbox to an accumulator on the drivers side.

Originally Posted by Dave.curley

2003. SL500
Had issues with leaking RR shock and did a lot of reading on the forum and decided to cut my losses and did the conversion over to the coil over strut, after a few weeks the car dropped back to regular height and drives and handles really well and don't need to worry about any more issues with the suspension. don't plan on having to put chains on or drive down any dirt roads, so it should work out fine.

Originally Posted by Welwynnick

https://mbworld.org/forums/cl-class-...op-mounts.html

I think most well-used W215's and W220's will suffer from this problem, and it can be easily fixed. The improvement to the ride and handling is really worthwhile on broken surfaces.

On the rear strut, the bush appears to be bonded to the metal mounting. I don't think this causes problems as readily as the front, but the bush can come free due to corrosion or bonding failure. The only solution I found was to replace the strut. Buy a good used one off ebay, and its not too expensive or difficult (as long as the so-called quick-release connector isn't seized).

I cut some small doughnuts out of a 10mm rubber sheet and put them under the top bush nuts. You need a stout 35mm pin spanner. Don't even need to lift the car up - in fact its better if you don't.

The ride is much better now. You can't do the same trick with rear struts unfortunately.




Its an angle grinder type of spanner that you need; not a C spanner.

The one that you linked on ebay looks suitable.

You can't use adjustable ones; they're not up to the job. Ask me how etc.

You use the spanner to undo the large flat nut on the top of the front strut, in the centre. You remove the electrical connector first.

Don't jack the car up - you need the weight on the wheel to stop the rest of the strut from spinning round (which may damage the hydraulic pipe).