Mobil1 5w30, 3600 mi, 2006 GMC Sierra 4.3l

[George7941]

Fe 11
Cr 1
Mo 68
Al 1
Cu 1
Pb 8
Sn 1
Ti 0
Ni 0
Ag 0
Si 24
Na 9
K 1
Zn 592
Mg 15
P 574
Ba 0

Soot 0
Sulf 22
Nitration 14
Antifreeze Neg
Fuel Dilution Neg
Water Neg


Mileage on truck is 16,600mi.

 

[pickled]

Your wear metals for the mileage on the oil look elevated to me. The elevated silicon could still be from factory sealants but I'd check your air filtration set-up and PCV hoses to ensure everything is tight. I don't remember elevated lead levels as being indicative of break-in with these motors, but I may be mistaken...it points more to a particulate streak across a bearing.

 

[addyguy]

Wear numbers aren't that bad, especially considering the amount of Si...I'd check your air filter. Additive numbers seem off - that zinc should be higher...let me guess, this was a CAT SOS Fluid analysis? they don't measure Calcium or Boron, for some strange reason...

 

[George7941]

It was a Cat SOS analysis.

Air filter element was replaced after my first UOA at 7500mi came back with high Si. I have thoroughly checked for intake leaks and have not found any.

The Si numbers are slowly coming down with more oil changes. I had Si at 72 on my first UOA at 7500mi on truck/ 3800 mi on oil. It looks like the high Si is from factory gasketing.

I read that with dirt ingestion, Al usually shows up with Si/Al ratio of 3.4:1, since the most common form of dirt has Si and Al in that ratio. Since my Al is only at 1, it is another indication that the Si is not coming from dirt.

I did a search on Bitog and came across this post of a GM 4.3L with high Si reading of 85
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=246516&fpart=1

 

[Al]

For that mileage..looks fine to me. Typical GM engine.

 

[George7941]

"Typical GM engine."

Is the high Si typical for a low mileage GM engine?


The lead, at 8 ppm, did not seem abnormal to me because I believe the Universal Average is around 9 ppm for oil with 3600 mi on it. I could be wrong, I am somewhat new to UOAs.

 

[JohnBrowning]

THe high Silicone seems out of place for a GM vechile since they do not normaly use RTV they use cut gaskets at all locations I believe. Now if it was a Toyota then the high silicone on a new low milage unit would be normal. I think you ahve a leak some place some duct work or a gromet is leaking! Get the silicone down and the wear will come down. The iron did not alarm me at all since this is a low milage GM and you as the owner are doing the finish machineing buy driveing it. THe lead number did bother me though. For such low milage the lead number should be lower.

Do me a favor if XD-3 is cheaper then M1 run either their 0W30 or 0W40 in this next time since we have plenty of time before winter arives. Both the 0W30 and 0W40 are thicker then M1 5W30. It is still a Mobil product so we can see if maybe your truck just likes a slightly thicker oil!

 

[George7941]

Thanks for the suggestion, I will try XD3 0w30 next time. I am currently running Formula Shell 5w30. Since I don't drive a lot, next oil change isn't due for a few months.

According to the Esso Tech Line,XD3 0w30 meets GF4 specs (which GM specifies for my truck) but 0w40 does not. If I remember correctly, GF4 has a limit of 8ppm of either zinc or phosphorous (I don't remember which one) and 0w40 has 12ppm.

 

[JohnBrowning]

Even thought the 4.3 is based on the old school Chevy Small Block I have always liked. If you can stay on top of any gasket leaks and such they are a really durable engine especialy in lighter vechiles like the old S-10 and in rear wheel drive cars etc.....In fact I will probably be building up a 4.3 in the not to distant future for some projects of mine! I want to see if I can find a stroker kit for them if not I will turbocharge one and probably drop it in an old land cruiser or old jeep! I do not like putting V8's in Jeeps,LandCruiser or Toyota compact trucks because things get really tight and I like to have space to work on things! The V6 gives you a lot more room to postion the engine in the ideal spot under the hood where a small block V8 forces you to work with what ever space is left over!

 

[George7941]

In my Sierra engine compartment, designed for a V8, the 4.3 V6 leaves a lot of clearance. Unfortunately, all the clearance is at the front of the engine and the rear of the engine has no more clearance than a V8 does.

There is a foot of space between the rad and the harmonic balancer. Water pump, timing cover, timing chain(if I ever have to replace it) are all super easy to get at. There is enough space to use an impact gun on the balancer fasteners without having to take the rad off. How many vehicles will permit that?