Viscosity thickening, long drain

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90,000km/10 years since my last oil change, Esso XD-3 0W-30 oil.

High temperature Viscosity thickening is a well known feature of long drains. But just searching, I'm not able to find any good material, UOA's, etc., on what happens to the cold temperature viscosity of motor oil subjected to long drains.

XD-3 0W-30 is a Group IV PAO oil, with very high viscosity index basestocks. After 90,000k (56k miles), its probably safe to assume that any viscosity modifiers have been depleted. But in an oil with minimal viscosity modifiers due to high VI basestocks, would cold-temperature viscosity thickening be significant?

Any good papers? I see one, "ASTM STP621_S4 Cold Starting and Oil Pumpability —An Evaluation of New and Used Oils in Gasoline Engines", but its very old (~1980) and implies that a 'used' 10W-30 becomes a 20W-40 in their case. Not sure such logic is applicable to modern synthetics though which don't rely upon viscosity modifiers.
 
Papers are often intertesting and informative background, but they won't tell you the status of your oil and engine. For that you need testing, DIY and/or contracted out.

UOA doesn't normally make sense to me since it costs more than an oil change, but here you're pushing the envelope into "research" territory, so it'd be justified, and if you havn't done it you perhaps should.

I'd also look into DIY viscosity and pH testing (which needn't be very precise to detect extreme changes) and "quality" testing like the blotter spot test.
 
I don't get why people like to stretch their oil changes this far. Oil is freaking cheap!
 
With a long drain like that and if the oil looks thick on the dip stick, I would have run the engine till warm then added
2 cups of kerosene and let it idle for 30 minutes, then do the oil change, you'd get it all out and the engine would be cleaner!
 
Cold weather performance generally slips as the oil is used. I believe slipping a "w" grade is acceptable in normal use. Over that OCI, I wouldn't venture a guess.
wink.gif
 
Originally Posted By: meborder
Quote:
90,000km/10 years since my last oil change, Esso XD-3 0W-30 oil


New gauntlet thrown down....


Pretty much.

I do not have the balls to try to top that.
 
Originally Posted By: pitzel
90,000km/10 years since my last oil change, Esso XD-3 0W-30 oil.

High temperature Viscosity thickening is a well known feature of long drains. But just searching, I'm not able to find any good material, UOA's, etc., on what happens to the cold temperature viscosity of motor oil subjected to long drains.

XD-3 0W-30 is a Group IV PAO oil, with very high viscosity index basestocks. After 90,000k (56k miles), its probably safe to assume that any viscosity modifiers have been depleted. But in an oil with minimal viscosity modifiers due to high VI basestocks, would cold-temperature viscosity thickening be significant?

Any good papers? I see one, "ASTM STP621_S4 Cold Starting and Oil Pumpability —An Evaluation of New and Used Oils in Gasoline Engines", but its very old (~1980) and implies that a 'used' 10W-30 becomes a 20W-40 in their case. Not sure such logic is applicable to modern synthetics though which don't rely upon viscosity modifiers.


I'd be curious to see what a used oil analysis would look like on this.
 
Originally Posted By: Linctex

I do not have the balls to try to top that.


I aim to try...not sure if either of us will get to the line, but my car has had it's last oil change.
 
Originally Posted By: 2004tdigls
nothing personal but this is a ridiculous OCI, just change the oil

I can't imagine what the inside of engine looks like

5 liters?

wow


Looks great internally. Had the oil pan off 2 years ago, and posted some pics here.

edit: see that a previous poster brought up the old thread. Just to clarify, the coolant leak was in 2008, which I repaired with a new LIM and a 2000km run of flush oil, and then loaded the current charge of oil. The oil pan was removed to install a new oil pan gasket to correct a leak. The oil was not changed with the oil pan change -- I cleaned everything up with brake clean and then drained it into a clean container and re-loaded the same oil into the engine. Approximately 5L of top-up oil were added over the 90k km's, but most of that was due to the leakage.


Quote:
What oil filter change interval do you use?


The manual says change every 15k miles with a half-sized. I use a full-sized filter which I've changed twice.
 
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