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Discussion Starter · #1 · (Edited)
See attached.

After analysis #2 (posted earlier) indicated the oil had diluted to an SAE 20 viscosity I had to change it. (MB must have factory filled with an SAE 30 viscosity in order to get better MPG numbers.)

Analysis #3 was immediately after the sump only (no filter) was changed and run to mix everything up, hence the 0.6% dilution number.

Analysis #4 was after one week of typical use, i.e. short trip commuting.

Analysis #5 was after an additional week of typical use.

Analysis #6 was after an additional two weeks of typical use. Here are the lab's comments after this analysis:

Check for source of FUEL LEAK. Fuel is at a SIGNIFICANT LEVEL. Fuel dilution may be caused by component faults related to injectors, ignition/timing or excessive blow-by. Additional causes include heavy throttle application, engine lugging, frequent short trips, and excessive idling. LUBRICANT and FILTER CHANGE is suggested if not done at sampling time. FUEL DILUTION has caused viscosity to decrease moderately; FUEL DILUTION reduces the viscosity of the lubricant which decreases FILM STRENGTH and LUBRICITY and may lead to increased wear. Resample at half interval; Your note was taken into consideration. (Emphasis in original.)

Analysis #7 was the day after #6 immediately following a 100 mile each way road trip. Only marginal improvement on the fuel dilution, surely to be followed by additional dilution with more typical use.

Needless to say, I am not a happy camper. By my estimates, after only five or six weeks of typical use the fuel dilution will be over 5%, the widely accepted critical level. I do not feel as though the car should have to be driven fifty miles every time it is cranked up just to avoid this problem. MB should be ashamed to engineer and market such a bomb.

I did my research before buying this thing and couldn't find a shred of evidence that the problem existed. So why doesn't anyone care about this issue? If your typical use is short-trip driving I would bet it is happening to your engine as well. Maybe folks do not care because they are in a lease. Now I wish I were. Maybe they are otherwise in it for the short term. I probably will be given this situation. Maybe they have so much money they just do not care. Must be nice. Or then maybe they are just a fanboy/sycophant. If so, they better wake up.
 

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Hmmmm....well I bought verses lease but I'm not going to have a loss of sleep and over analyze my oil.....I guess thats why having a four year warranty is enough for me because by then I will be ready to move on to a newer version of Mercedes whatever it may be....I'm sure the lab is happy to have your money but you should be careful not to stereotype people until you look into the mirror.....
 

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Doyall: Do you have similar test results from other cars? Would be interesting to compare. Also, what caused you to have your oil tested?
 

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Discussion Starter · #4 ·
Hmmmm....well I bought verses lease but I'm not going to have a loss of sleep and over analyze my oil.....I guess thats why having a four year warranty is enough for me because by then I will be ready to move on to a newer version of Mercedes whatever it may be....I'm sure the lab is happy to have your money but you should be careful not to stereotype people until you look into the mirror.....
Who did I stereotype?

But you did out yourself as a dual club member ... lessee and fanboy/sycophant.
 

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Discussion Starter · #5 ·
Doyall: Do you have similar test results from other cars? Would be interesting to compare. Also, what caused you to have your oil tested?
Previous car (2011 Cadillac SRX) had the same problem. Over many different forums people have problems with the GM High-Feature V6 no matter what product it is in. It is not just isolated incidences. Seems as though just about any direct injection engine will do it. I had my oil analyzed for just this reason.
 

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After analysis #2 (posted earlier) indicated the oil had diluted to an SAE 20 viscosity I had to change it. (MB must have factory filled with an SAE 30 viscosity in order to get better MPG numbers.)
MB factory SAE30 for fuel economy? I don't think so. The higher the SAE number, the higher the viscosity, hence more drag and lower fuel economy. Factory fill should have been 0W-40, which would have better economy that 20W or 30W

Why would you be thinking single grade oil? Filling with anything but multi-grade oils went out in the '60s.
 

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Who did I stereotype?

But you did out yourself as a dual club member ... lessee and fanboy/sycophant.
Yes I apologize for that.....I'm just in the too much money I don't care category....lol
 

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Discussion Starter · #8 ·
MB factory SAE30 for fuel economy? I don't think so. The higher the SAE number, the higher the viscosity, hence more drag and lower fuel economy. Factory fill should have been 0W-40, which would have better economy that 20W or 30W

Why would you be thinking single grade oil? Filling with anything but multi-grade oils went out in the '60s.
Maybe I should have been more specific and said SAE 30 viscosity at 100 degrees Celsius (which is one method operating viscosity is measured) or 0/5W-30 to be less than accurate. Some 0/5W-30 oils are among the MB-approved 229.5 oils specified for the engine, and therefore could have been used as factory fill.

An SAE 40 viscosity at 100 degrees Celsius (or 0/5W-40 if you will) is more viscous (i.e. thicker) than an SAE 30 viscosity at 100 degrees Celsius (0/5W-30) and will therefore be less economical, however marginally. Here is the chart:
 

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On a more serious note....doyall have you reported your findings to the dealers service department and have they looked at modifying your ECM or ECU to alleviate the issue your experiencing or are they just putting you off...or you could have leaking injectors when the car is resting...maybe you have already looked into these possibilities that I don't know....

Seems to be an interesting topic so I added some reading for those who want to know more about the MB engine used in the GLA....
 

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An SAE 40 viscosity at 100 degrees Celsius (or 0/5W-40 if you will) is more viscous (i.e. thicker) than an SAE 30 viscosity at 100 degrees Celsius (0/5W-30) and will therefore be less economical, however marginally. Here is the chart:
Please don't mix your oil weight terminology. You referenced a viscosity chart for straight weight 40W oil. For GLA, we are only talking multi-grade, be it 0W-40, 5W-40, or 0W-30. As you can see comparing these two Mobil products 40W has a much different viscosity range, and rate of viscosity change with temperature compared to 0W-40. Yes, they are roughly equivalent at 100C, but I would think anyone exacting enough to regularly test their motor oil would want to be exacting in their terminology. ;)
 

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Discussion Starter · #11 ·
On a more serious note....doyall have you reported your findings to the dealers service department and have they looked at modifying your ECM or ECU to alleviate the issue your experiencing or are they just putting you off...or you could have leaking injectors when the car is resting...maybe you have already looked into these possibilities that I don't know....

Seems to be an interesting topic so I added some reading for those who want to know more about the MB engine used in the GLA....
I am just gathering the data to present to the dealership. Probably will wait until I get a 5% dilution reading before I do that. But I suspect I will run into the same brick wall I did with GM, whose rep (not a dealership employee) told me the information I wanted about fuel dilution in the GM HFV6 was proprietary, that they were not going to do anything about the fuel dilution my engine was experiencing because it wasn't "throwing any codes" and that if it quit running during warranty they would repair it. Therein lies the problem ... what if I want to keep the car after the warranty is up. The fuel dilution problem is one that will manifest itself after any warranty or extended warranty expires. GM is essentially building in an "early wear out" feature in the name of short-term efficiency. That is one reason I got rid of the SRX and why I will never buy another GM automobile. I hope MB does not take that stance but I doubt there are going to be any modifications that MB will be willing to make to remedy the problem as it will probably negatively affect driveability, emissions, economy, etc. I am beginning to believe that the phenomenon is inevitable in a direct injection engine that is not driven significant distances after every cold start.
 

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Discussion Starter · #12 ·
Please don't mix your oil weight terminology. You referenced a viscosity chart for straight weight 40W oil. For GLA, we are only talking multi-grade, be it 0W-40, 5W-40, or 0W-30. As you can see comparing these two Mobil products 40W has a much different viscosity range, and rate of viscosity change with temperature compared to 0W-40. Yes, they are roughly equivalent at 100C, but I would think anyone exacting enough to regularly test their motor oil would want to be exacting in their terminology. ;)
Sorry. Too used to talking to oil heads about it.
 

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Previous car (2011 Cadillac SRX) had the same problem. Over many different forums people have problems with the GM High-Feature V6 no matter what product it is in. It is not just isolated incidences. Seems as though just about any direct injection engine will do it. I had my oil analyzed for just this reason.
Thanks for the clarification, Doyall. I have a 2007 Pontiac Solstice GXP, and as far as I know, haven't had any issues related to oil, but also haven't had the oil analyzed, either! FYI, the GXP is a turbocharged DI in-line 4cyl as well, the LNF engine, I believe. It was, as far as I know, the first production turbo DI engine ever made by GM, and was also, at the time, the highest specific output engine ever made by GM. I frequent the Solstice owner's forums as well and haven't heard of this ever being a problem, though unless excessive wear is found or the oil is analyzed I don't know how anyone would know.

Maybe I'll post over there and see what they say.... that group is very knowledgeable about turbo DI engines.
 

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is I am beginning to believe that the phenomenon is inevitable in a direct injection engine that is not driven significant distances after every cold start.
How far do you drive after cold start? My commute is about 6 miles, and typically takes less than 15 minutes. In the winter my temperature gauge often doesn't reach 80C.

Like you I purchased and plan to keep my GLA for quite a while. I'm an engineer and work for a supplier to Daimler. Knowing how Daimler engineers think and the Daimler engineering process was one of the reasons why I picked the GLA over other OEMs. On the other hand, I know that if you miss something in your development test plan, it can come back to haunt you later. Despite their claim of millions of durability miles, or even the cold weather tests run in development, if they didn't include a test duty cycle that covers your situation, could have totally missed the problem.

Please keep us updated on what response you get from MB.
 

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Discussion Starter · #15 ·
How far do you drive after cold start? ...
Typical commute to work is ten miles, eight of which are on the interstate.

... Knowing how Daimler engineers think and the Daimler engineering process was one of the reasons why I picked the GLA over other OEMs. ...
I was likewise resting my hopes on what I perceived to be the best engineering in the world to have conquered this problem.

... Despite their claim of millions of durability miles, or even the cold weather tests run in development, if they didn't include a test duty cycle that covers your situation, could have totally missed the problem. ...
As this is certainly far from a new phenomenon with this technology, it would have been, in my opinion, grossly negligent to overlook this. And I have no doubts about the multi-mile durability statements. As an example, I could change the oil/filter in my prior car (hate to keep bringing it up), immediately set out on a 350 mile one way trip and pull a sample for analysis on return to find 0% dilution BUT after five days of the 10 mile one way commute it would already be at over 5% dilution. But everybody doesn't have a two hour daily commute and people just can't be expected to drive a car 50 miles from every cold start. After more research when the MB diluted the oil, my best take on preventing dilution in the first place is that the engine will probably have to be run at speed (no idling) for at least twenty minutes AFTER the oil (not coolant) is up to operating temperature. Depending on ambient temperatures it could take ten to fifteen minutes or more for the oil to get to temperature. Since MB didn't give us an oil temperature gauge/dashboard reading, we can never truly know when it first reaches temperature.

Here again, I hope I am wrong but I can't help but think MB trusts that new car owners will not become this (and I will say it for bellermb's benefit) obsessively involved with their vehicles and that any problems will not occur until after the warranty expires. I am surprised that they did not offer free oil changes for the warranty period in the belief that it would help it not to be discovered.

... Please keep us updated on what response you get from MB.
I will whether anyone wants me to or not.
 
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