3RZ 235k miles Rotella 5W-40 5k interval

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Oct 12, 2010
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Hey folks,

First oil analysis on my 99 4Runner with 3RZ-FE engine. At the time of the oil change the engine oil (Rotella 5W-40 CJ-4) had about 5000 miles on it and the engine had 235k.

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Everything looks good except for the 180ppm of sodium. The lab states that they think it comes from the oil additives but both the CJ-4 and CK-4 VOAs don't show sodium: https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/4490450/1/Shell_Rotella_T6_5W40_CJ-4/SM_

Comments?
 
You're right that sodium would not be expected in any Rotella 5W40...did you use a different oil for the change before this one?
Maybe something like Valvoline or Royal Purple? There could be some carryover...
I'd think you would have potassium as well if there was a coolant leak, but maybe that would depend on exactly what type of coolant you used.
 
Virtus, thanks for the thoughts.

My previous fill was Valvoline Synpower 5W-30. Perhaps that's part of the issue. Would you expect that much Sodium carryover to be possible?

Coolant is factory Toyota Red.
 
Originally Posted By: JZiggy
Virtus, thanks for the thoughts.

My previous fill was Valvoline Synpower 5W-30. Perhaps that's part of the issue. Would you expect that much Sodium carryover to be possible?

Coolant is factory Toyota Red.


Valvoline oils have high sodium as in their add pack so it could well be a carry over. As stated if you had an internal coolant leak your potassium level likely would be high, it's not. I find it interesting that oil has lower calcium and higher magnesium as with Dexos 1 gen 2 oils to combat LSPI. It's even higher in ZDDP which also helps combat LSPI. The UOA looks real good for a 200,000+ mileage vehicle.

Whimsey
 
Good info about the potassium. I also am not aware of any chance in coolant levels and no other evidence of contamination.

Maybe I'll run another UOA later and see if the sodium goes away. This next fill is T6.
 
Blackstone agrees the sodium is likely carryover from the previous fill. Since there is zero potassium the likelihood of coolant is small.
 
I frequently use Valvoline - Usually MaxLife and/or NextGen, but sometimes Synpower - and I frequently see this kind of sodium carry-over. If that was your last fill, then I wouldn't worry about it at all, especially since the potassium is 0.
 
Originally Posted By: SirTanon
I frequently use Valvoline - Usually MaxLife and/or NextGen, but sometimes Synpower - and I frequently see this kind of sodium carry-over. If that was your last fill, then I wouldn't worry about it at all, especially since the potassium is 0.


Thanks, that is very helpful!
 
Another 5000 miles, another oil report. Seems pretty much the same with some lingering sodium for some reason. What else can this come from...?

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Well, at least it is tracking down. I would, however, have expected it to come down more than this, unless 3/4 of the sump remains behind during on oil change.
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How many fills has it gotten since the last Valvoline one?
 
Before 230,000 miles it was running Valvoline. At 230,000ish it got T6 plus a new filter. I then changed the oil (T6) without changing the filter at 235,000 and did a UOA on this oil. At 240,000 I changed both oil and filter and did a UOA. Perhaps retaining the filter at 235,000 allowed the residual Valvoline to continue to carry over?
 
So, it hasn't been all that long. I'm not sure of the filter size, but irrespective of that, a filter will retain some oil. It still seems a bit high, but I have no idea how much used oil that engine retains, let alone with the oil filter being kept. So, all you can really do is keep monitoring it. I'd have thought it would have come down quicker, but given how recent the Valvoline was, and the filter hanging on, at least we have a somewhat plausible explanation.
 
That's my thinking too. The cooling system never loses a drop so I'm not really concerned about a leak. I guess I'll just have to get another UOA next year
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The wear metal values are consistent so far and confirm me thinking that this 3RZ has lots of life left in it.
 
Thanks Garak!

I did an oil pan gasket job on this engine. Should I expect the next fill to show anything weird because of it? Si from the silicone rubber...?
 
What makes you choose T6 for high miles gasoline engine? I just like to learn if there is a secret
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Lots of recommendations. Great track record. So far UOAs show it's pretty happy.
 
Updated UOA! Some interesting stuff going on in this one...

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1) High iron: In the course of this interval the vehicle spent nearly 1000 miles in an offroad scenario. It also pulled a LOT of grades through the Sierras at 4500rpm WOT. I pushed it HARD. This may be what I paid for it.

2) High silicon: Just before the interval it got a fresh silicone FIPG oil pan gasket and had a valve cover gasket change to do valve adjustment. I think that's the issue, but I have also been experimenting with an oiled foam air pre-filter. But the factory air filter is still in place and I don't think the seal is compromised.

3) Sodium: It's still there in a meaningful amount of sodium. I can't believe anymore that this is lingering sodium from a valvoline fill years ago. Either there's actually sodium in this oil or it's aspirating a bit of coolant, right? The vehicle still doesn't consume any coolant so unless this is just from a trace leak I'm stumped.

Also it looks like the Rotella's formulation is updated (think it's CK-4 now) and the moly is gone. Might be a good time to switch to an oil with some moly to help with wear if ya'll recommend this.
 
The iron is inconsequential. The silicon number, as you mention, could have a few things going on there. That's the problem when we've got a couple variables that can contribute to one thing. As for the sodium, that is odd. I have read that sodium can be more persistent than one would expect from previous fills, taking longer to go down than some other numbers. All you can do with that is watch.

I wouldn't rush to switch brands or lines. HDEOs have very often not had any moly content, so it should be no surprise. Moly content that we see in most motor oils isn't sufficient for AW, but only friction modification. To get into the AW regime for moly, you'd have to transition to a boutique like Red Line (and that product creates UOA anxiety as well) or some of the unicorn OEM Japanese fills that had moly out the wazoo, along with trying to locate it in the first place, much less in the correct viscosity.
 
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