PP/Mobil1 5w-20/0w-30 4.5K Jeep 4.0

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Jul 2, 2007
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689
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Chicago, IL
My buddy did a analysis with Blackstone a while back after I suggested it to him. '94 Grand Cherokee with the 4.0 @ 140K. Evidently the store had only 3qts of PP and 4qts Mobil 0w-30. He was going for thin stuff but I don't think the 5w-20 helped. He did 3qts of PP and 3.25 of Mobil. This sample is from winter use here in Chicago, uses it mainly for work so it sees 50/50 city/highway with a lot of built up idle time. He's also a lead footed driver. About half minute warm up times when started from cold. ALUMINUM 5 CHROMIUM 2 IRON 65 COPPER 2 LEAD 3 MOLYBDENUM 69 POTASSIUM 2 BORON 35 SILICON 12 SODIUM 10 CALCIUM 2145 MAGNESIUM 13 PHOSPHORUS 620 ZINC 767 cSt Viscosity @ 100°C 9.02 SUS Viscosity @ 210°F 55.8 Flashpoint in °F 340 Fuel % 0.8 Antifreeze % 0.0 Water % 0.0 Insolubles % 0.3 No TBN Normally he runs a 5w-30 in winter and switches to a HDEO in the winter. Don't really have anything to compare it to since it is the first analysis but the iron is up there. I know the long idle times aren't helping but he needs the motor running in order to power some equipment on site.
 
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That iron number is rather high for a 4.0 (insert obligatory joke about how it *must* have been that M1 in there. ) Blackstone's "universal average" is 28, my result was 19 at a few hundred more miles than this test. I seriously doubt he drives it harder than I do, either. But there's no real conclusion to be drawn. Is it because its a 5w20/0w30 mixmess? (doubtful, but you can't rule it out)? Is it because its an SM oil with low P in a flat tappet engine? FWIW, I've got a fill of SM rated RTS in mine now, but that's not going to fully answer the question either since SM rated RTS has quite a bit more ZN and P than passenger car oils (almost as much as an SL PCO).
 
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gomes512

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Jul 2, 2007
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Chicago, IL
Yes I fully agree it is high. My 4.0 sees about what your seeing 440, running Rotella 10w-30. I have no idea if it was the mixing or the low P + Zn or the idling that did it... Just figured this was an interesting oil/engine combo and result. I'm curious to see what his summer analysis will look like with Rotella 15w-40.
 
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Iron is high, but all other metals well within the comfort zone. Not bad for a thin(er) mix in a big iron lump of an engine.
 
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