Low Viscosity with Mobil 0W40, Concerned?

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Had a good UOA using Mobil Euro 0W40 in 2013 Mercedes SLK230 1.8 liter Turbocharged.
4600 miles with 35,000 total miles on car. Used no oil.
I only do 5K or less on my oil changes not the 10K recommended by MB

SUS Viscosity at 210F is 58.0 should be 64to 74
cST Viscosity at 100C is 9.65 should be 11.3 to 14.3
fuel %
Comparing this to others using Mobil Euro 0W40 my viscosity seemed to drop a lot.
Blackstone comments were "the low viscosity isn't a problem"
I'm wondering if this turbo engine is especially hard on oil. My previous SLK was a 2.3 liter Supercharged and didn't have low oil viscosity on excellent UOAs.

I'm considering trying Castrol 0W40 Euro with Titanium on next oil change.
Is Titanium an advantage?

What do you guys think?
 
Well that 0w40 seems to be a thin 40 to begin with.


M1HM 10w30 reads viscosity at 100 C at 12.1 cst.
M1 0w40 shows 12.9 cst at 100 C

Perhaps is there another oil that meets specs that is like
5w40 or sits a little thicker at operating temp?
I dont think it gets cold enough to NEED a 0w anything in south texas.
 
Originally Posted By: Stevie
Had a good UOA using Mobil Euro 0W40 in 2013 Mercedes SLK230 1.8 liter Turbocharged.
4600 miles with 35,000 total miles on car. Used no oil.
I only do 5K or less on my oil changes not the 10K recommended by MB

SUS Viscosity at 210F is 58.0 should be 64to 74
cST Viscosity at 100C is 9.65 should be 11.3 to 14.3
fuel %
Comparing this to others using Mobil Euro 0W40 my viscosity seemed to drop a lot.
Blackstone comments were "the low viscosity isn't a problem"
I'm wondering if this turbo engine is especially hard on oil. My previous SLK was a 2.3 liter Supercharged and didn't have low oil viscosity on excellent UOAs.

I'm considering trying Castrol 0W40 Euro with Titanium on next oil change.
Is Titanium an advantage?

What do you guys think?



I had similar results to yours running M1 0W-40 for years in my 2.0L GDI Turbo Kia Optima SX with a similar OCI of under 5K miles.
I switched to Castrol Edge 0W-40 and have been getting better lab results (as per Polaris).

I'd recommend you switch and rerun your testing to see the results.
 
If I t is a direct injected turbo you probably have some fuel dilution as well. If the UOA is good I wouldn’t sweat it.i run the edge in my bmw but I also have the M1 0w40 in the hopper for a 4 runner.

Btw.
How is the rebuild going in Port A.? I am a corpus native who is landlocked for the past 9years. Hard to shake off the salt in my blood.
 
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Originally Posted By: JAG
It’s almost certainly due to a lot of fuel dilution. Does it get a lot of short trips?


This.
 
Originally Posted By: CharlieBauer
Are Blackstone known for not measuring fuel dilution correctly?


Correct.
 
Originally Posted By: OVERKILL
Originally Posted By: CharlieBauer
Are Blackstone known for not measuring fuel dilution correctly?


Correct.
+1 - their methodology allows for subjective analysis. Try using Polaris in the future.
 
Thanks for everyones input! You guys are so smart! My trip to work is 9 miles each way. Most road trips are taken in my wife's Hyundai since my SLK won't hold us and our dog.

How far of a drive would I need to burn off the fuel dilution every month or so?

I guess the dilution isn't hurting my engine or turbo if I keep the oil changes around 5K?

Mobil 1 0W/40 or Castrol Euro 0W/40? What about that Titanium in the Castrol?

Sorry about all the questions, but I would like to keep this SLK for a long time as I really love it. I want to do everything I can to treat it right.
 
I get fuel dilution on my non GDI Gen Coupe turbo. They have loose rings. One guy on the forum was surprised as instead of using oil the level increased. Mine uses no oil at all in 5k miles, I assume it does and the fuel is replacing whatever is burnt.
 
Originally Posted By: Stevie
Thanks for everyones input! You guys are so smart! My trip to work is 9 miles each way. Most road trips are taken in my wife's Hyundai since my SLK won't hold us and our dog.

How far of a drive would I need to burn off the fuel dilution every month or so?

I guess the dilution isn't hurting my engine or turbo if I keep the oil changes around 5K?

Mobil 1 0W/40 or Castrol Euro 0W/40? What about that Titanium in the Castrol?

Sorry about all the questions, but I would like to keep this SLK for a long time as I really love it. I want to do everything I can to treat it right.



I switched from M1 0W-40 in my GDI turbo 2.0L Kia Optima SX to Castrol Edge 0W-40 for this reason. My Polaris reports show a vast reduction in oxidation and less viscosity loss after similar OCI and driving style/mix. My fuel dilution is correctly measured by Polaris as greater than 5% with both oils. My conclusion is that the Castrol holds up better in my hot little GDI turbo engine.
 
Originally Posted By: Stevie
Thanks for everyones input! You guys are so smart! My trip to work is 9 miles each way. Most road trips are taken in my wife's Hyundai since my SLK won't hold us and our dog.

How far of a drive would I need to burn off the fuel dilution every month or so?


In your climate, I think 9 miles twice a day is pretty good.

Please share what the universal averages are with that engine.

Also, when you took the sample, how long had the engine been running beforehand.

First thing is to ask Blackstone to rerun the viscosity and fuel dilution test. Second would be to get another labs opinion.

In the meantime, do you know if this is common with this engine? Have you checked the various Mercedes forums?
 
Originally Posted By: CharlieBauer
Originally Posted By: Stevie
Thanks for everyones input! You guys are so smart! My trip to work is 9 miles each way. Most road trips are taken in my wife's Hyundai since my SLK won't hold us and our dog.

How far of a drive would I need to burn off the fuel dilution every month or so?



Please share what the universal averages are with that engine.

Also, when you took the sample, how long had the engine been running beforehand.


I had run the engine maybe 2 miles before oil change.
The UOA:
HbmjeIS.png
 
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Thanks. I forgot the universal averages don't report viscosity, fuel dilution etc.

I would say running 2 miles only could have introduced fuel. So best to question Blackstone on why such a robust oil has thinned so much if there is no fuel and to have viscosity and dilution tested again.

They could also pull up other uoas and let you know if others have low viscosity as well.

What is your 9 mile commute like?

You might want to run Techron concentrate or Gumout Regane in case your injectors need a clean and are contributing to possible fuel dilution.
 
Originally Posted By: CharlieBauer
Thanks. I forgot the universal averages don't report viscosity, fuel dilution etc.

I would say running 2 miles only could have introduced fuel. So best to question Blackstone on why such a robust oil has thinned so much if there is no fuel and to have viscosity and dilution tested again.

They could also pull up other uoas and let you know if others have low viscosity as well.

What is your 9 mile commute like?

You might want to run Techron concentrate or Gumout Regane in case your injectors need a clean and are contributing to possible fuel dilution.

Some fuel injection cleaners from Wynns and BG claim that they are specially designed for GDI injectors, and they might be a better choice.
 
Originally Posted By: Stevie
Thanks for everyones input! You guys are so smart! My trip to work is 9 miles each way. Most road trips are taken in my wife's Hyundai since my SLK won't hold us and our dog.

How far of a drive would I need to burn off the fuel dilution every month or so?

I guess the dilution isn't hurting my engine or turbo if I keep the oil changes around 5K?

Mobil 1 0W/40 or Castrol Euro 0W/40? What about that Titanium in the Castrol?

Sorry about all the questions, but I would like to keep this SLK for a long time as I really love it. I want to do everything I can to treat it right.



You cannot burn of fuel dilution effectively. With Etahnol, you can (but cavitation might be an issue). But Petrol/gas (can't remember which is the english and wich the american word) is a mix of a [censored] of a lot of different compounds. Some of which have a boiling point below the operating temperature of engine oil, some of which don't. And you really DO NOT WANT to run an engine hard at high revs and full throttle in order to create high oil temperaures, whith a compromised oil. I remember stumbling across an article in a german motorist magazine from the 80s or 90s, where they simulated on a test bench a typical short-tripping scenario until the fuel reached 10%, followed by a summer vacation (load the car to it's max capacity and drive 1500km from northern Germany over the Alps deep into Italy, and as your kid's are bored and annoying, you want to get there fast, so full throttle on the Autobahn bits and full throttle on the mountain passes in the Alps.) After that, they disassembled the engine - it was toast. Bearings were worn, and the cylinders were polished. Oh, and even then, there were still significant amounts of fuel present in the oil.
Lesson to be learnt: don't try to "cook off" severe fuel dilution. Just don't.


To control fuel dilution you have to fix the underlying issue (temperature sensors, MAF sensor, lambda sonds, etc). If there is no technical issue to be fixed and the fuel dilution is the result of either the driving profile (i.e short tripping) or engine design (some DI engines run perversely rich in certain conditions to prevent LSPI), then the only viable option to control the amount of fuel in the oil is to reduce OCI.
 
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