Silicon in oil

[Spetz]

Hi everyone,

I have had 2 UOA done and both showed high (30+) levels of silicon in the oil suggesting unfiltered air is entering the engine.

The car idles poorly at times, so initially I thought a vacuum leak must be causing both the idle issues and the silicon content, however a smoke test did not reveal any leaks.

Any suggestions of what I can do to test where unfiltered air is coming in from?

This is for a 2003 Mitsubishi Diamante.

 

[Drosselmier]

A good start would be to check the air filter for condition and good fit.

 

[Snagglefoot]

Have you had any bad bush fires in the area this year? Suspended smoke particles can make it through filters if they are fine enough.

 

[Spetz]

I did check and replace the air filter.
It fits tight. I am not sure if I should put some kind of grease on the rubber surrounds though?

No bush fires.

I did change filter brands (I went for a better known and more expensive brand) however this did not change anything in the UOA.

 

[CharBaby]

Are your UOA showing any presents at all of Anti-Freeze/Coolant?...Any?

 

[Lubener]

Originally Posted by Char Baby
Are your UOA showing any presents at all of Anti-Freeze/Coolant?...Any?

Potassium would also be elevated.

Look for loose or poor fitting air intake ductwork.

 

[Spetz]

No signs of coolant, water potassium in the UOA.

If the silicon contamination is before the throttle body, the leak should be quite significant I would assume?
In contract if it is after the throttle body then a small leak under high vacuum conditions would allow lots of unfiltered air?

 

[ARCOgraphite]

I would check PCV hoses then, intake piping then maybe IM gasket next.

I had a split in a newish Mazda 626 in the rubber intake hose from the airbox to the throttle. The "crack" would only "open up" under throttle when the engine torqued over and pulled on the hose.
I didn't find it until I had disassembled everything from airbox to throttlebody and did a careful inspection of each component.

My FMA was: poor quality material (rubber) that was too stiff during sub zero weather and spit when strained.
Car was only 2 year old.

So be thorough.

p.s.: Also your EGR must be dead by now too.

 

[sloinker]

I know some of the boutique oils show an elevated Silicon level that has something to do with their add pack.

 

[kschachn]

Originally Posted by sloinker
I know some of the boutique oils show an elevated Silicon level that has something to do with their add pack.

https://www.machinerylubrication.com/Read/377/silicon-dirt-oil-analysis

Again a problem with reading too much into a UOA because ICP only sees elements and has no idea what compounds they are from. Always good to compare against a current VOA (as is often pointed out on this site but equally often ignored).

 

[sxg6]

What brand/model air filter? If it's a k&n or something similar, that's the culprit.

 

[Spetz]

It's a standard paper filter, not a cone type.
The brand is Ryco which is an Australian brand of filter and (at least in Australia) appears to be well regarded

 

[Snagglefoot]

It appears you need to remove the Ryco filter from the equation and try another brand. May I suggest an OEM or Fram.

 

[Eddie]

To find a small vacuum leak I might try a can of starter fluid or something similar. With a running engine Spray in very short burst along any connection or seam to see if the engine rpm changes. Ed

 

[Spetz]

Can I use an unlit butane torch instead?
I just read that starter fluid may ignite...

Also, I've had a smoke test done and nothing had showed up