2011 Civic R18 2.7k/22k Idemitsu 0w20 - High Si

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I did an intermediate sample in my Civic in the quest to find the source of high Silicon and Aluminum in my UOAs. The obvious suspect is an intake leak, but I've been unable to track it down. Previous UOA is here.

Blackstone's comments on this UOA are worse than useless. If this oil were run to 6,700 miles, one would expect Si to be 43 ppm and Al to be 60 ppm, which is even worse than the last sample. It seems the electrical tape fix I made to the air filter housing didn't help, and possibly hurt.

The other interesting thing about this UOA is the additive levels, less Moly, but more Boron and Zn/Ph. The oil is Subaru OEM API SM supplied by Idemitsu, but it's an obviously different formulation from the previous OCI which came in the same bottles labeled API SM. It's also clearly different from the VOA that lukoil did on the Subaru/Idemitsu oil. It seems clear there are two different oil formulations being sold by Subaru which are labeled as API SM. I suspect I got two bottles of each, as this UOA is about halfway between my previous UOA and lukoil's VOA. It's quite possible that the SN formulation is coming packaged in bottles still labeled SM. When I change the oil out, I'll do a KV40 measurement on it, we'll see how it comes back.

OilReport22268miforPosting_zps30ed2b54.jpg


After getting this UOA back I continued my quest for the intake leak. Still nothing obvious. This time my search has centered on the filter itself. The OEM filter is made by Filtech, and appears of excellent workmanship. The housing is also made by Filtech.

The OEM filter gasket is a stiff rubber like the window seals on the doors of a car rather than the foam rubber type which would be more like a soft rubber door seal. Applying petroleum jelly to the gasket and installing the housing showed somewhat uneven sealing to the housing. My hope is that by using a filter with a slightly thicker gasket, that sealing will be improved.

The aftermarket filters I checked out had both kinds of gasket and substantial variation in thickness and workmanship. I took some pictures and notes of the various filters and the housing, when I have time, I'll start a detailed post in the filter section about it.

The car now has a NAPA Select (formerly silver) in it now. Is this a WIX? The NAPA gold had more filter pleats and an obviously different filter material, but the gasket seemed inferior to the select version. The NAPA select filter had a stiff rubber gasket similar to the OEM gasket, but taller, which would result in more compression when installed in the housing. The gold filter has a soft, foam rubber gasket which is thinner than the select gasket. It also had obvious workmanship irregularities, like mold flash and sealing surface irregularities. The silver filter's gasket was cosmetically perfect. I also examined a Purolator Classic filter and a Fram, the Purolator had a stiff gasket, but it was quite thin, the Fram gasket was very similar to the NAPA gold, soft, thin and irregular.

If the Si/Al levels don't drop by the next oil change, I'll start looking for leaks in the intake manifold itself. I find it hard to believe such a leak wouldn't light the CEL, but I suppose it's possible.
 
Strange.
Makes me want to get a UOA done on my car, since you can't track down the source of high SI. Although it is trending down in your previous reports.
I have pretty much just run blind and mostly followed my OLM which I am sure is probably fine, but I have seen a few other R18 reports that do not share your trend, thats for sure.
Thanks for sharing.
 
Yes, probably a formulation change before the bottles were relabeled but Idemitsu would probably tell you. If you want help in getting to the cause of the problem, try Terry Dyson.
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-Dennis
 
Originally Posted By: bluesubie
Yes, probably a formulation change before the bottles were relabeled but Idemitsu would probably tell you. If you want help in getting to the cause of the problem, try Terry Dyson.
19.gif


-Dennis


Which problem? The formulation "problem" or the intake leak? I won't be using the Subaru 0w20 any more, if I want high-VI and Moly I'll buy the Mazda oil. My dealer is a Mazda/Subaru dealer any way.

I doubt Terry can find a hole in my intake tract from 1,000 miles away, though if he can he'd certainly be worth his fee.

I've entertained the idea that the Silicon is from the pistons as well, being that hypereutectic pistons have substantial Silicon in them, but the ratio of Si to Al still looks too high. Given my Al numbers and a 17.5% Si content in the pistons, I'd expect 5-7ppm of the Si to be from the pistons, but it's still substantially above the 15ppm I'd expect to see in a UOA showing good filtration.
 
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