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High silicon reading in oil sample

K

KRAUSEGB

Well Known Member
Oil analysis have shown high silicon reading (22ppm) the last three times.
I have cleaned the filters according to the recommended methods each time but still getting these high readings.
Anyone have some ideas as to how I am getting dirt entering the induction system or is it something else?

Gary
 
Silicone

Look over entire induction system carefully. All clamps, hoses and gaskets are suspect. Also look at how well the airfilter seals to the airbox.

Don Broussard

RV 9 Rebuild in Progress
 
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KRAUSEGB said:
Oil analysis have shown high silicon reading (22ppm) the last three times.
I have cleaned the filters according to the recommended methods each time but still getting these high readings.
Anyone have some ideas as to how I am getting dirt entering the induction system or is it something else?

Gary
Click to expand...

Some good ideas here, have you used RTV as a gasket sealant before the first high silicon samples? See Blackstone site and silicon.
 
Are you using DC-4 or other silicone lubricant for the oil filter gasket? I have noticed that will cause a spike.

Vic
 
High readings on occasions are common especially with silicone. It is not cause for alarm. It can come from several sources. Look for trends and not always a single test. If a reading is serious then take another sample in 10 hours or so. Make sure your samples come from have way through the oil drain. You do not want the top or bottom oil from the tank. With your higher than normal silicone sample I would just wait until the next oil change. Keep the air filters clean and keep products with silicone away from the fuel system.
 
Thanks to everyone

Thanks for the input on possible sources of silicon.

Question-Is there a problem if it turns out that the source in RTV contamination? Is this a serious problem with the engine, causing wear as would be the case with sand/dirt?

Gary
 
As I understand it, silica is dirt, and silicone and silica are quite different from one another. I think:confused:
DaveH
120485
 
daveyator said:
As I understand it, silica is dirt, and silicone and silica are quite different from one another. I think:confused:
DaveH
120485
Click to expand...

That's what I thought too, and I was a little confused... so I looked them up.
Silicones are polymers that include any inert, synthetic compound made up of repeating units of siloxane, which is a chain of alternating silicon atoms and oxygen atoms, frequently combined with carbon and/or hydrogen.
Click to expand...
Silica: the dioxide form of silicon, SiO 2, occurring especially as quartz sand, flint, and agate
Click to expand...

So... silica and silicone can, if I understand correctly now, both be a source of silicon in an oil sample. Maybe if I'd had a better Chem teacher in high school I'd have known that before I was a hundred years old.
 
I've always wondered about the real value of oil analysis. We used it in the utility industry and the Navy to monitor equipment (particularly bearing wear), but I wonder if a little knowledge is dangerous in most GA owner applications because it can cause us to fret over things that don't really matter. I have never done oil analysis on any of my planes because I don't think most end users (including me) have the expertise to interpret the data. The oil filter contents and mag plug appearance seem much more relevant to us GA guys. The exception to this would be an analysis program performed by the engine manufacturer with their recommendations.
 
I've had high silicon readings on my O-290-D2 high compression engine since day one. I have a good K&N filter on the ram air intake, no filter on the carb heat, silicone rocker cover gaskets, silicone intake tubes, silicone oil return tubes, and I used red RTV to seal my K&N filter. I never fly off of dirt strips. I've taken extra care not to contaminate the oil sample, yet the readings are always high (45, 26, 44, 35, 24). The original 45 reading was after the first oil change @ 15 hrs.; The 44 reading in the middle was after a long cross country flight with no oil change for 54 hrs. Compression is still 78/80 or better after two years so I'm just not going to worry about it. It has to be the silicone rubber or the Camguard that I always use.
 
Isn't it more about trends than absolute readings? If a wrist pin starts rubbing or a ring breaks and starts chewing stuff up you get a spike and it will cause you to start looking deeper before the failure becomes dangerous (theoretically)?
 
Blackstone Lab told me to change air filter after oil analysis. Did and next sample back to normal.
 
checked my results from spectrum labs in new jersey. values range from 5 to 12ppm. :cool: yours sound acceptable to me.
 
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