Silicon from Silicone gaskets ?

Messages
738
Location
Suburban St. Louis
I posted a not-so-good UOA with a lot of Silicon. Blackstone had asked if the engine had been opened for work, and that the silicon (119 ppm) could be from sealants, etc. I had replaced the valve covers, intake manifold, and oil pan gaskets with premium silicone gaskets. A number of people added some good comments to the UOA, but nobody directly addressed the real question: "Is it likely that the silicon in the report is from the silicone gaskets ?" Does anybody think that it's not possible ? Should I be more worried than I am ? The interval turned out to be essentially the rinse phase of my A-Rx application also. This confuses things too. UOA thread here
 

Al

Messages
19,277
Location
Elizabethtown, Pa
Well, with the high aluminum and iron and lead it certainly could be that the silicon is partially from air intake. But I don't have enough experience. I would check the air filter/intake very closely and go another 3K interval and see what's up. In that short of run you didn't hurt anything.
 
Messages
1,130
Location
California
With all of the variables you have in play it is hard to reach any conclusions. I would say that high silicon readings could be due to the new silcone gaskets and any sealer you used. A thorough check of the intake manifold, PCV system and air filtration path for any leaks would also be well worth while. I would then do two short interval changes of around 1,000 miles with whatever oil you plan to use long term without any extra things (Auto RX, etc.) and *then* do a 3,000 mile interval followed by an oil analysis. I'm old fashioned in not liking to add anything to the motor oil, AutoRX included. You might not do things the way I would though [Smile] . John [ May 19, 2004, 09:46 PM: Message edited by: jthorner ]
 
Messages
9,365
Location
USA
I'm in somewhat of the same predicament. my oil pan gasket is leaking. I want to do a UOA on my next oil change but if I replace the gasket, Silcon will be through the roof. <b>how many oil changes you guys think will take to flush out most of the silicon from a oil pan gasket? and at what intervals?</b>
 

MolaKule

Staff member
Messages
22,108
Location
Iowegia - USA
If you had been doing UOA testing and trending, the spike in silicon would show after the pan gasket replacement, and with your previous baselines, you could determine how much was gasket silicone and how much was elemental silicon such a dust and dirt. I have seen it take as many as 20,000 miles before the leaching had subsided.
 
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