Second analysis from BLACKSTONE LABORATORIES from oil sample take during last oil change:

OIL: Castrol GTX 5w-20 (Standard stuff)
MILES ON OIL: 8,127

RESULTS: In my car all the elements were in the normal range. The TBN, however, went down to 2.1. Blackstone stated that "the TBN of 2.1 shows active additive still remaining in the oil after a longer oil run. Try running 9,000 miles on the next fill and then resample to monitor wear." I was 167 miles past the 0% indicator at the time of the oil change/sample.
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In the previous sample of Castrol GTX 5w-20 sent in with 6,811 miles on the oil, the TBN was at 2.7. All elements were in the normal range as well. Computer was showing 15% oil life at this point.

In light of the Castrol oil doing well, I went with Mobil One Full Synthetic (5W-20) in this last oil change. I'm going to let the Mobil One oil go to to 9,000 miles. Currently, the computer is showing that oil life is at 20% with 6,650 miles on the oil.

 

Didn't want to beat a dead horse, or hijack a thread, but this is a fairly recent post...

Since I've owned my car, I've used Mobil1 5000 5w20 spec oil. Everything has been great...
I've done this, up until about ~9k miles ago (just found out tonight), when I decided to buy the big jug at WalMart instead of the individual quart, which is 5w30.

From my understanding, it isn't necessarily a bad thing, especially since I live in TX - however it is approaching winter.
I *assume* that the cold spec will help suffice for the winter, while the hot spec will help when a) the engine reaches core temp, b) during hot summers ~115 degrees F.

I haven't noticed any issues after ~9k and 2 oil changes; no visible leaks, and no known oil consumption. I don't get any sluggishness (which I believe would indicate blow-by) either.
I have yet to change the head gasket, but my reasoning is "if it ain't broke, don't fix it." Sound reasonable?

Any thoughts on my reasoning? Or should I go back to the 5w20?

 

Doing a change soon... any input?

Bueller... Bueller...

 

You say "Mobil-1 5000" oil. No such thing...
There's Mobil-1 oil which is full-synthetic.
Then there's Mobil 5000 oil which is petroleum. It's not labeled "Mobil-1".

If it's Mobil-1 synthetic, do some browsing at bobistheoilguy dot com. I sorta remember something about Mobil-1 5w-30 leaning a bit on the thin side of 5w-30, so it seems OK.

Even if it's the petroleum Mobil-5000 stuff, it's probably OK too. How cold does it get in Texas in winter anyway?

 

Sorry, the "5W" is the key in the cold. In the summer you might be able to fudge with a "10W". If in AK, then I'd look into a "0W" for the winter.

 

Eh in TX it can get down to 20, maybe even down to 0 on occasion (not too frequent though). During the summer it will be 95-105 regularly, and on occasion get as high as 115.

I'm not so concerned with the cold spec, more of the hot spec... is the 30w going to be too much over time vs the 20w?
Like I said, I've been running 5w30 for 12k miles, and no issues that I can tell -- just wanna make sure I have my understanding right.

 

Okay, so is the consensus that one doesn't need to "bump up" the viscosity of a car's oil once it hits 80,000 to 100,000 miles? The reason I am asking this is due to the Autozone guy stating that he is currently attending some automotive school where he was told that after hitting 80,000 miles one should go with a heavier oil. For example, in my car that would be 10W-20, not the current 5W-20 I am using. We were specifically talking about my daughter's Jetta GL when having this discussion, as I was buying stuff for an oil change. Her car requires 5W-30 and he was recommending 10W-30 due to the car having 140,000 miles.

What say you guys?

 

What school is that?

Personally have over 370K on a Honda motor and still use the same weight oil as the manual says...just me.

 

Some local tech college thing probably. I dunno, as I didn't ask him.

Okay, well, I guess the answer is a resounding "no," at least in your case. Good to hear that your Honda is still chugging along!

 

I wouldn't change oil viscosity unless there's some actual reason to do so. Simple miles isn't a reason.

If the oil pressure is getting low (actually measured with a gauge) or if you actually KNOW that the bearing clearances have worn big, then OK. Otherwise, stick with what works.

I think the so-called "high mileage" oils have extra additives for leaky seals, which is a more common thing in high-mile engines. Still, I wouldn't even use those unless there's an actual reason.