Silicone Levels in Ford/Toyota Engines

[TooSlick]

All Toyota engines and almost all Ford engines - including the 4.6L/5.4L/V-10/7.3L - will show high silicon levels for the first 50,000 miles.
These engines use a glob of "Permatex" type sealant to form the oil pan gasket. Small amounts of this material are also used in other places - at the ends of the camshafts for example.

If you see high silicon levels in one of these engines, do not assume it's dirt. Look at the levels of wear metals that are used in the intake system, such as nickel/chrome/aluminum/iron. Also look to see if bearing wear, ie lead is elevated.

The silicon levels from my 2.4L Tacoma engine dropped from 50 ppm every 10k miles to 10 ppm every 10k miles. However, it took 50,000 miles for these levels to stabilize.

 

[mikep]

Thx for the tip. I guess this would explain the 11 ppm in my 4.6 Triton v8. Like you said, the wear metals were all very low so no biggie. Be interested in seeing if the the Si levels come down on my next UOA.

Thanks again.

Mikep

 

[jsharp]

quote:

---

Originally posted by mikep:
Thx for the tip. I guess this would explain the 11 ppm in my 4.6 Triton v8. Like you said, the wear metals were all very low so no biggie. Be interested in seeing if the the Si levels come down on my next UOA.

Thanks again.

Mikep

---

I swapped the K&N air filter for paper in my V6 4Runner to see if there was any difference next UOA. If not, this might help explain it to me...

 

[Roger]

I don't suppose there is any chance that's true of Nissan engines too?

Mine's had a pesky high silicon reading for 20K now.

 

[unDummy]

Nissan has been globbing on the RTV for oil pans/thermostat housings.....
Unless seriously elevated, I wouldn't worry too much about it.

How much SI is introduced to the oil/filter during normal maintenance? Some engines require contortionist movements to install filters(with normal undercarriage dirt dropping all over the place). Throw in the dirt around the oil filler neck during filling/topoffs and you're going to see the SI numbers climb.

 

[unDummy]

I'm bumping this because I'm just wondering,
Is SI 'silicone' or 'silicon', and what are the oil labs actually testing for?
Which one is FDA bringing back?

Which one is dirt? Which one is antifoam/oil additive?

Maybe this deserves its own thread. I think that there is confusion between the two.

 

[TooSlick]

Undummy,

Silicon/dirt and silicone sealer both look the same to a Mass Spectrometer, and therein lies the dilemma.

If you suspect dirt, look for elevated metals from the intake tract and combustion chambers.

Tooslick

 

[Robbie Alexander]

quote:

---

Originally posted by TooSlick:
Undummy,

Silicon/dirt and silicone sealer both look the same to a Mass Spectrometer, and therein lies the dilemma.

If you suspect dirt, look for elevated metals from the intake tract and combustion chambers.

Tooslick

---

Yes, but also remember that some OILS will have the new additives with the SI make-up and the oil will have a higher concentration of it's own SI from the oils virginity.