What % fuel dillution would warrant dumping oil

[Donald]

Of the prior 3 UOAs for my Powerstroke, 2 had fuel dillution of
The oil was changed when the OLM came on a little under 8000.

Now with a bypass filter and synthetic diesel oil like T6 I should be able to go more than 8000 miles but may need to dump it because of fuel dillution.

So what % is bad enough to warrant dumping the oil?

 

[OneEyeJack]

I'd try an "Italian tune up" and see what reduction you might realize.

 

[Donald]

Originally Posted By: OneEyeJack
I'd try an "Italian tune up" and see what reduction you might realize.


I avoid things like that.

 

[resist]

Is there a thermostat in the oil cooler on that engine? Sounds like you are taking short trips or the oil is otherwise not heating up enough to "boil" off the fuel contamination. Or is the engine real worn out?

 

[BrianF]

I think I heard to look at dumping around the 5-6% fuel dilution. Now dont quote me on this. But I never read too deep into why these new Powerstrokes require such a short oil change index.

A bypass filter and T6 will not solve a fuel dilution issue. That is caused by either a worn out engine or a lot of forced DPF regens. Longer trips and getting the truck up to operating temp will help this issue.

As far as I am aware you cant really burn off diesel fuel dilution, its not like a distillate that can boil off.

 

[benjamming]

It depends upon how the oil is handling all that fuel. Not all oils are created the same. UOA can help guide you.

 

[Shannow]

I just took 7+ litres of oil out of the "new" Captiva. Presuming that at the last service they put in 6.2L, that's nearly an extra litre.

Did a business card blotter test, and it showed virtually zero dispercency, despite
Extreme example, and probably a lot of moisture in it too...but 2% shouldn't worry you.

 

[Shannow]

Originally Posted By: OneEyeJack
I'd try an "Italian tune up" and see what reduction you might realize.


Due to the distillation curve of diesel, Italian Tuneups don't do a great deal.

 

[Shannow]

That's the blotters...

get in a habit of doing them and getting used to what your engine does, and you'll have a rough reckoner of where your oil is up to.

 

[Ducked]

Originally Posted By: Shannow

That's the blotters...

get in a habit of doing them and getting used to what your engine does, and you'll have a rough reckoner of where your oil is up to.


Uh?

Havn't gone back to look at any reference pics, but from memory (and intuitively, for the little that's worth) your Colorado (which I assume is sort of your "control") looks a lot less dispersed than your Captiva.

 

[Ducked]

Originally Posted By: Shannow
Black, thin and smelly. ATF from the power steering reservour beaded on it rather than immediately mixed.


Not heard that one before, though there was some discussion/argument about the implications of the behaviour of oil droplets on water a while back.

IIRC with modern oils the implications for that were fairly unclear. How does ATF compare?

 

[Bailes1992]

When I got my UOA I was advised by Millers Oils that 2% was a warning, 3% was cautionary and 4% was 'dump the oil". That said my oil was a good 1/4" above the max mark last week, I've driven around 600miles of high speed motorway driving since and it's back down to the max mark so it does seem that you can 'boil off' the diesel.

 

[Ducked]

Looked for a ref. picture here

http://www.machinerylubrication.com/Read/51/soot-oil-engine

and rather wish I hadn't bothered.

As usual with these things, your samples don't quite look like any of the examples.

In this case there's the added irritation in the text that they say:-

"When dispersancy begins to fail, the insolubles begin to form a dense ring on the exterior of the absorbing oil drop as seen in Figure 6C"

This would be fine if I could see that in Fig 6C, but I can't.

Still, even with the interpretation difficulties, your Colorado still looks less dispersed to me.

Here's another one, from here

http://www.adsystems-sa.com/dt100dl.php

Colorado looks most like 3 (to me). Captiva between 1 and 2

http://www.machinerylubrication.com/Read/29353/evaluating-lubricant-dispersancy

Colorado looks most like 5 (to me)

 

[Shannow]

Changed the oil in the Captiva today, and after Mrs Shannow got it all mixed and good and hot did another...it's the one in the middle.

What I've seen following my Nissan is they look like the middle one, then centre gets darker, and the "striations" take form.

I've only ever seen a couple like the Captiva initial one, and not on something that I'm maintaining...usually people who have flickering oil lights and can't remember last change.

 

[Shannow]

Originally Posted By: Ducked
Not heard that one before, though there was some discussion/argument about the implications of the behaviour of oil droplets on water a while back.

IIRC with modern oils the implications for that were fairly unclear. How does ATF compare?


Drain pan is one of these...

So had a couple of square feet of black stuff, as I turkey basted the power steering fluid out of the reservoir.

The oils always "smear" into each other, "clinging" due to their surface tension as soon as they touch.

Today the Power Steering Fluid "beaded" when squirted into the collection area on top of the engine oil.

 

[Jetronic]

did the engine oil bead on the dipstick aswell? They tend to do that with lots of diesel mixed in.

 

[Ducked]

Originally Posted By: Shannow

Changed the oil in the Captiva today, and after Mrs Shannow got it all mixed and good and hot did another...it's the one in the middle.

What I've seen following my Nissan is they look like the middle one, then centre gets darker, and the "striations" take form.

I've only ever seen a couple like the Captiva initial one, and not on something that I'm maintaining...usually people who have flickering oil lights and can't remember last change.


OK, if that's what they do, then it is.

Suggests to me that you'd need to establish your own time course, and that published pictures are pretty useless as a guide to interpretation.

 

[Ducked]

Originally Posted By: Shannow
Originally Posted By: Ducked
Not heard that one before, though there was some discussion/argument about the implications of the behaviour of oil droplets on water a while back.

IIRC with modern oils the implications for that were fairly unclear. How does ATF compare?


Drain pan is one of these...

So had a couple of square feet of black stuff, as I turkey basted the power steering fluid out of the reservoir.

The oils always "smear" into each other, "clinging" due to their surface tension as soon as they touch.

Today the Power Steering Fluid "beaded" when squirted into the collection area on top of the engine oil.


While since I read up on it, but I THINK the story with oil/water was that, as oil degrades, polar compounds develop which reduce the surface tension because they're attracted to the polar water molecules, so the oil no longer "beads" on water but spreads out as a thin surface layer. This behaviour is/was used as an indicator of oil degredation.

I suppose the ATF story might be the reverse of that. The contaminated oil is polar (like the water) and the uncontaminated ATF beads on it because it isn't.

In practice, modern oils have a lot of polar surfactants (dispersants, detergents, maybe friction modifiers) in them straight out of the bottle, so maybe the method no longer works as a reliable indicator of degredation.

www.nttworldwide.com/docs/camtel

The Role of Interfacial Tension Measurement in the Oil Industry. Carole Moules, Camtel Ltd.

Has a comparison of surface tension measurements for clean and dirty motor oils which show no systematic differences and are all very much less than those for sunflower oil.

 

[Ducked]

Just to add, IF ATF is non-polar, the test should work in reverse (oil drop on ATF) so you might have revived the oil-drop test in another form, (though ATF is more expensive than water).

If ATF isn't non-polar (ATF perhaps varies) it shouldn't be very difficult to find something more defined (kerosene, liquid parafinn, ?) that would do the job.

AFAICT this modified test would still be subject to interference by polar compounds in the oil formulation, though.

 

[Ducked]

ANOTHER automotive use for sunflower oil? (see above ref).