UOA on new car

[alexanderfitu]

Hi all

After my UOA from Millers (in the UK) I decided to use a different company in the UK. (they said everything looked ok, then the engine died)

This is for my 2008 S65 AMG (M275 V12 Bi turbo). 98,000 miles. I think 10,000 miles on this oil.

When I bought the car (recently) one of the tabs on the airbox was broken off, and then outlet of the air filter wasn't making good sealing contact with the inlet of the turbo, I think that explains the high silicone.

Otherwise, your input is very much welcome. Thanks.

 

[Donald]

I think the higher than normal silicon may be gasket sealer. While it's a tad high, it's not wearing the engine from the iron/copper/lead/nickel number of that all seem pretty low.

 

[alexanderfitu]

Originally Posted By: Donald
I think the higher than normal silicon may be gasket sealer. While it's a tad high, it's not wearing the engine from the iron/copper/lead/nickel number of that all seem pretty low.


Thanks Donald. I have no reason to think that the engine has been apart recently. Would that silicon reading come from sealant that's been there a while?

 

[Donald]

The higher than normal silicon readings due to gasket sealer come down after a couple of oil changes.

If you think the air intake is tight then skip this oil change for a UOA and do one the next.

At a high level your looking for low metal contaminant numbers which you have. Silicon does not matter much if not causing any wear, thus the silicon particle size must be low. That's why a gasket sealer is suspect.

 

[alexanderfitu]

Ahh I see.

Yes, I think the silicone reading is from contaminants due to the airbox.

Thanks, I will do another one in 10k miles time.

 

[kschachn]

By the way, it is "silicon" not silicone. The ICP analysis detects elements only, not compounds.

Which also contributes to the uncertainty of origin since you don't really know where the silicon comes from. Both silicone and silicon dioxide are silicon and oxygen (although silicone contains other elements in the side groups). It would be difficult to determine which one it is, and one could be quite detrimental while one would be mostly harmless.

 

[alexanderfitu]

Originally Posted By: kschachn
By the way, it is "silicon" not silicone. The ICP analysis detects elements only, not compounds.

Which also contributes to the uncertainty of origin since you don't really know where the silicon comes from. Both silicone and silicon dioxide are silicon and oxygen (although silicone contains other elements in the side groups). It would be difficult to determine which one it is, and one could be quite detrimental while one would be mostly harmless.


Sorry, auto correct keeps changing it for some reason!

So basically I should ignore it for now as the source could be either bad or good and as it and be determined, the information is not useful.

 

[kschachn]

Originally Posted By: alexanderfitu
So basically I should ignore it for now as the source could be either bad or good and as it and be determined, the information is not useful.


Well I didn't say that but others did. It is a common consensus here that high-ish silicon readings in early UOAs are due to silicone sealing compounds, which may be true. I don't know since I don't know how your particular manufacturer assembled the engine. My Toyota cars were assembled using Toyota FPG, that much I do know. But my BMW had almost no sealant at all (gaskets instead). But I don't think I would worry about it since the number is really not that high.

 

[alexanderfitu]

Right. I see.

Great, I'm not worried either. I will see how it progresses. Many thanks.