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Thanks again. So bottom line, it sounds like the CRC injected where you did it (turbo inlet pipe), cleans the turbo, all the intake components and intake valves .
Just had a chance to catch up with your rebuild... that's awesome work man! I'm glad everything worked out well after the engine went back in. Wow, you mostly did the work yourself...with a little help from your dad, lol. Now that your GL has been back in business, is it still running smoothly?
Are you a mechanic? These tools to rebuild the motor is not something the average Joe has laying around in their garage, nor a job an average person will want to jump into, lol.
Your post definitely has my interest when I first read it, because my '13 GL550 has been having subtle intermittent vibrations at idle/stop that I started noticing around 66k miles. I'm now at 71k.
Eta: forgot to mention that this issue with cylinder 5 is starting to look like a common problem that Mercedes know about, but don't want to acknowledge to fix due to the costs of repairs. A other member just posted about #5 problems.
Most of the tools is Harbor Freight. Not certified mechanic, but have doctoral degree in science. Basically just mess around with cars i have.
Car running good. Still waiting for first 2k after rebuild to replace oil. Check engine still on. Need Xentry to reset it. Don't want to pay 300 to dealer.
Hahaha, dont blame you. I call them the stealership.
I guess I better start looking for HF coupons to pick up the engine lift, lol. You got that cylinder boring contraption at HF too? I guess I will only need the cylinder bored/sleeved if it was as damaged as yours... but otherwise it would just be swapping the heads only for loss compression, correct? But, somebody mentioned that possible source of this problem may be the cylinder/ sleeve not pressed in properly. So, if only replacing the head, wouldn't this problem occur again because the cylinder/ sleeve wasn't corrected? I'm going to start looking for heads, parts and service manual on Ebay and online...
Used heads for the engine will fit from any m278 engine generation. S550 CL550 CLS550 and so on. Not necessary GL class. GL heads significantly overpriced because of not many of those available for parts stripping. I've got two heads without camshafts for about 250 dollars each from eBay. You will have to recondition it and resurface since mercedes uses MLS head gaskets.
I pulled old one apart to rebuild and keep it just in case and very curious why it leaked. Will check valves, valve guides, and valve seats geometry over weekend. Will post results. Since i have a leak in one valve only it is not a case there it been hit by something.
I suspect that back flow from turbo overheats some of those and manufacturing defects causing leakage. We will see.
Originally i had absolutely no intentions to rebuild engine, just wanted to swap head.
My '13 is somewhat 'clattery' at 103k, but it has been since I've owned it.
No check engine codes besides a fluke P013E00 'Rich/Lean Switchover of Oxygen Sensor 2 (Cylinder Bank 1) is Delayed' that went away on it's own. Xentry showed 'Injector Injection quantity adjustment for cylinder balancing has almost reached the upper limit value at at least one cylinder. There is a signal above the permissible limit value.'
Mode 06 shows Cylinder 5 misfiring maybe twice per normal run, nowhere near value for throwing a CEL. Spark plugs changed at 55k, likely time again. Should I run for cover? Seems like most with the head replacement faced the issue at 50-70k. My engine serial number is outside the range stated in the TSB shared somewhere in mbworld, which may or may not mean anything.
I wouldn't worry much about it as long as CEL off. You can run dynamic compression test in Xentry to clear thing out.
Meanwhile got myself another toy. e320cdi with OM642.
Last edited by arsupisemnet; 11-09-2019 at 10:17 PM.
And thanks, will relax slightly. I need to do the timing chain tensioners and check valves but don't mind the rattle on start-up, as long as it's not causing other issues.
Keep it for sure, it is like a little jet...
Only reason i rebuilded it...
New car is a project and commute. I drive about 2-3k miles a month - with 15 mpg on GL kind of expensive.
Had some time to continue rebuilding original cylinder heads. Regrinded intake valves. All good. No bent valves. Damaged two of valve in grinder chuck, so will replace those.
With exhaust valves different story. Six exhaust valves came out good after grind. Nine valves came out with slight asymmetry in grind contact surface - which we deducted to poor manufacturing of valve itself, since we found two raw cast surfaces on valve steams, and one came absolutely asymmetric - the one which leaked pressure (presumably either bend or being worst in production batch)
Thanks for the update! Based on what you've experienced and noticed, I am shocked at the poor quality and tolerance of precision parts, such as these valve stems.
Now back to the subject of failure. There are many theories why Silitec liners fail. From what i've seen in my engine i concluded to the engineering failure. I will try to explain what is going on.
Silitec liner is an alloy of Aluminum with 25% of Silicon and so on. During engine block manufacturing cylinder surface bored to the necessary specs and after that acid etched. The reason for etching is to remove aluminum from the surface of cylinder walls exposing Silicon crystals matrix which is extremely hard. You can go through manufacturing process just googling it. Basically final result is ceramic "wall" made of polycrystalline Silicon.
If you will take any ceramic surface and move aluminum stick across it you will see a grey line made of grinded aluminum. Which basically raises a question - how do aluminum pistons survive within the SIlitec engine?
And the answer will be - Iron Coating. All pistons for Silitec engines has thin iron coating on the surface of piston skirts. As long as this iron coating exists - your engine is good. No issues withing cylinder walls no problems no lack of compression no misfires.
Once that thin iron coating gone - you start scratching piece of aluminum on the ceramic surface. Not only it results in wear and damage of piston skirt, also because aluminum soft metal it tear crystals of the Silicone from the cylinder walls matrix , and stuck to it on the friction surface, basically grinding everything around to the pulp. Will have pictures of damaged pistons uploaded tomorrow.
Now for those of you who still have no problems, ideally if you will rebuild your engine with fresh set of pistons every let say 70k miles and hone cylinder walls - your engine will last for a long time.
To be continued
have an class action lawyers contacted you about these failures? Cylinder walls and valve guides shouldn't be failing within 36 months and 100,000 miles. These are problems on vehicles between 200,000-300,000.
Well, you are buying high end high performance car. It lasted as long as its technology suppose to be lasting.
Normally people who can afford it brand new will get another one at 75k miles.
So I had a 545i N62 motor that lasted 13 years and 180,000 before SMG unit failed and needed valve stem seals. Porsche Cayenne Turbo I had went 185,000 before I burnt a valve (partly my fault I was towing a boat on a two lane highway got a misfire too dangerous to stop). The TSB is from 2015 well within the warranty period. This is not a "high end high performance" problem. N54 can push 550whp for 200,000 miles properly maintained. Internals shouldn't fail like this.
Regular intervals. Old tech. Cast iron.
The problem will be your crankshaft bearings - those will go out eventually. There are no repair sizes for given engine unless custom made or custom swap from previous generations (as long as you know repair diameter).
I purposively replaced bearing to new ones during rebuild.
If you feel like enhancing engine to avoid valve problem you can order custom made Inconel valves. As a matter of fact they cost almost as much as original from MB. Those installed in drag racing motors and can handle anything
About the original one. The block itself if properly maintained will last a century. You have to swap pistons every 70k miles though and hone block with special hones. It is the damage to piston coating result in wall scratching and wear out.
Now, you can't install original pistons with iron coating in cast iron sleeves. MB has either special pistons for cast iron blocks (there are none cast iron blocks, i assume it is sleeved ones). Or you have to send it for a performance coating as i did - there they sandblast off iron coating and will coat it with racing coat for regular blocks.
I'm contemplating a similar rebuild on my 2006 ML350. I have bore scoring and pitting resulting in poor compression in two cylinders. I contacted LA Sleeve for a price but they could not identify the custom iron sleeves they made for you.
Could you share your order number please, or some way to get a cost estimate off them? I am also considering oversize pistons and re-etching the Silitec as I have the profilometer..
Could you also advise the wall to piston clearance, presumably measured after the pistons have been coated?
Thx!
10-22-2019, 10:12 AM
