Best properties in an oil to slow oil consumption?

[TugaSaudade]

Hi everyone.

I own a 1.4 VW engine (AUB code - 101bhp) bought with 87k miles on it.
It takes 3.38 quarts of oil to fill the engine.

Not knowing this car background, i did a flush using pro german brand SONAX and changed the oil with Shell Helix Ultra 5w40.
(sold in US as Pennzoil Ultra)
I used this oil mainly because its VW50200/503.01 grade and was not expecting oil consumption..

But it went thru around 1 quart of oil in about 600 miles..
Manual states that up to 0,5 quart oil consumption is considered normal..
But that does not explain why quite a lot of other owners with the exact same engine are able to go up to 9.000 miles with NO oil consumption.

Took it to a local dealer, no oil leaks detected, compression test was 14,5 - 14,5 - 16 - 16, even higher than the 10,5 VW says it should be.

Engine revs up fine, plenty of power, no smoke that i can see, no oil smell..


Don't know if i have a sludge issue, i only did an engine flush to be on the safe side.

First with SONAX, a german kerosene/xylene based flush, 10m@idle.

Then another one with Shell Helix Ultra 5w40 already in the engine and after 1200 miles (and almost 2quarts worth of top up's), with Xado specific "Vitaflush", driving 120 miles
with it as XADO instructions stated, before changing to thicker Castrol mineral GTX 15w50 with the xado cermet inside.

I kept the "old" (1200 miles) oil filter, allowed the remaining oil to drain from it completely during several weeks and measured its weight after.
It was 2.47 ounces heavier compared with a same brand new..

So 2 engines flush's in a 1200 mile period.
XADO cermet did not worked either, even with a thicker oil.

Also read here in BITOG were Dr. Haas research was mentioned, that a thiner 30 weight oil could have a better result in reducing oil consumption thru the rings, although that does not make much logic to me..

I have no ideia what's causing the oil consumption, but the faster i run the car, the faster it goes thru the oil..

Tried Castrol GTX High Mileage 15w40 mineral oil but oil consumption increased to 1qt/400 miles.. so this oil is not a valid solution in trying to slowdown consumption rate.

Based on all the knowledge here in BITOG, what properties should i look in the next oil choice, until i have the money to get the piston rings replaced?

Can i reduce engine oil consumption by choosing an oil that "buys" me both the time and peace of mind as far as engine health goes, until i'm able to tear the engine apart?

 

[d00df00d]

As I understand, oil consumption can be helped by either a thicker or a thinner oil, depending on the cause.

Sometimes, oil consumption is caused by air entrainment: over long periods of use, especially if this is at high RPMs, air gets trapped in the oil and causes the oil level to rise, which increases vapor pressure in the crankcase. A lower viscosity oil might reduce oil consumption in this case, since it would release trapped air more easily.

Other times, oil consumption is caused by the oil slipping past the piston rings. This is where a higher viscosity oil, or simply a tougher one (e.g. synthetic), might help.

These causes of oil consumption can be addressed to some extent by looking at spec sheets. Here are my suggestions for what to look for:

- Low kinematic viscosity ("weight" -- i.e. xw-30, xw-40, etc.)
- High viscosity index
- High HTHS viscosity
- High flash point
- Low volatility

Now, another cause for oil consumption is fuel dilution (fuel getting into the oil). In this case, the best solution is engine tuning, not oil choice. Oil choice can help, but the problem is that how an oil reacts to fuel dilution depends on chemical properties that usually aren't indicated in the spec sheets. There will be a lot of trial-and-error involved unless you are paying a consultant like Terry Dyson to guide your choices with oil analysis (in which case there will only be some trial-and-error.

)

Hope that helped.

 

[Bill in Utah]

Hi,

No magic oil. Nothing that is going to FIX the rings (if that is the problem) or reduce significantly the amount of oil usage.

The only thing that is going to "buy" you peace of mind as far as engine health is to REPAIR the engine. I hope you don't have cats in your exhaust system down there. They are taking a beating if you do. Expect more $$$ to be spent on them, O2 sensors and such if you continue to operate this engine with that much oil being consumed.

Have you checked the PVC system in the engine?

Good luck! Bill

 

[d00df00d]

Yes, Bill makes a good point that I was wrong to leave out. It's always best to address the engine first, and then the oil. Check your PCV system, your sensors, and your compression levels, and go from there.

 

[StevieC]

Look for a good NOACK rating...

 

[TugaSaudade]

It did helped, by at least pointing me to the right direction

I did had the ECU tuned to improve MPG, but it had already this oil consumption issue..
If i'm facing a problem caused by fuel dilution, should i be aiming to a thicker fully synthetic oil like Mobil 1 5w40, 0w40 or even 5w50?

I was considering one of those "clinging" Castrol Magnatec semi synthetic 10w40 or a Full Synthetic 5w40.. or even Mobil 1 0w40 if it had better chance of lasting longer in the engine..

The goal is to achieve the best cost/protection ratio by choosing an oil that as a better chance of lasting longer, without risking engine protection until i get the money to rebuild the engine..

I can always keep on toping up, but i´m not sure if i´m risking engine failure caused by fuel dilution in the long term..

Considering that Pennzoil Ultra 5w40 lasted 600 miles until reaching top-up point, should i aim to a PAO oil?
And thicker or thinner?

 

[StevieC]

Thicker PAO oil I would say. Can't fix the fuel dilution problem?

That will help with the consumption in most cases.

 

[Bill in Utah]

Originally Posted By: TugaSaudade
It did helped, by at least pointing me to the right direction

I did had the ECU tuned to improve MPG, but it had already this oil consumption issue..
If i'm facing a problem caused by fuel dilution, should i be aiming to a thicker fully synthetic oil like Mobil 1 5w40, 0w40 or even 5w50?

I was considering one of those "clinging" Castrol Magnatec semi synthetic 10w40 or a Full Synthetic 5w40.. or even Mobil 1 0w40 if it had better chance of lasting longer in the engine..

The goal is to achieve the best cost/protection ratio by choosing an oil that as a better chance of lasting longer, without risking engine protection until i get the money to rebuild the engine..

I can always keep on toping up, but i´m not sure if i´m risking engine failure caused by fuel dilution in the long term..

Considering that Pennzoil Ultra 5w40 lasted 600 miles until reaching top-up point, should i aim to a PAO oil?
And thicker or thinner?

Your engine IS FAILING. THE MORE YOU RUN IT THE WORST THE DAMAGE TO IT AND OTHER SYSTEMS!

FIX IT... Oil choice does NOT MATTER..

If you can not fix it stop driving it and SAVE MONEY till you can..

 

[TugaSaudade]

Compression is 14,5 - 14,5 -16 - 16
Even higher than the 10.5 VW states in the car's manual..
And it does have 2 cats.. a primary one just next to the engine, and another one in the exaust line..

Would looking for a mid or low saps oil buy me some time?

Oh my.. i just can't fix it right now..
Forgive me for asking.. but what is "NOACK"?

 

[d00df00d]

Originally Posted By: TugaSaudade
Compression is 14,5 - 14,5 -16 - 16
Even higher than the 10.5 VW states in the car's manual..

Check those numbers with a master technician at a dealership service department.


Originally Posted By: TugaSaudade
Would looking for a mid or low saps oil buy me some time?

Possibly. You might have to change it at shorter intervals though.


Originally Posted By: TugaSaudade
Forgive me for asking.. but what is "NOACK"?

It's a volatility measurement.




...But more importantly, I just re-read your opening post and saw that you've done several chemical treatments and tried several different oils. Switching oils can cause higher-than-normal oil consumption, so at this point you have no way to tell what you're dealing with. Stick with one oil (make it low-SAPS if you want, but make SURE it meets the specs in your owner's manual) for at least three oil changes and see what happens.

 

[expat]

Do you see blue smoke? Can you get someone to follow you to check for smoke?
If it smokes, does it happen during Acceleration or deceleration?
I'm thinking it may require valve stem seals (that could be installed with the engine in situ)

 

[440Magnum]

Quote:

Also read here in BITOG were Dr. Haas research was mentioned, that a thiner 30 weight oil could have a better result in reducing oil consumption thru the rings, although that does not make much logic to me..


Its very true in some cases, and since your compression is good you could be such a case. The rings that provide compression are completely different from the ring that controls oil consumption. The upper rings on the piston are solid-faced rings that seal to the cylinder wall and prevent gas from leaking past the ring... but they don't do a thing about preventing oil consumption because they just "ride up" over any oil that is on the cylinder wall. The *bottom* ring (or rings, depending on design) doesn't seal gasses in, but its specifically made to scrape excess oil off the cylinder wall and prevent it from entering the combustion chamber. Usually its a stacked set of 2 thin scraper rings separated by a spacer that allows the scraped oil to drain away from between the 2 scraping rings. If the ability of that ring to scrape oil is weakened (like from damage due to chemical flushes breaking loose material and beating it up or clogging the openings in the spacer) then it has a hard time scraping enough oil off the cylinder and oil consumption shoots up even though compression and performance are fine. A thinner oil *may* be easier for the weakened oil-control ring to "scrape" than a thick oil is, so you actually burn less of a thinner oil (within limits, of course). It doesn't always work that way, but sometimes it does.

 

[TugaSaudade]

Ok.. thank you guys for all the help so far.

Stoping the car is not a possible option, so that leaves me with "damage control".

Portuguese Castrol sells oil analysis in packs of 10 (!) only, making it EXTREMELY expensive to go that way trying to confirm fuel dilution with a UOA.

My wife drove the car around at several speeds as i followed her, and i did not noticed any visible smoke.. tail pipe looks black inside..

So, as sugested, i'll start searching for a 30 or 40 weight PAO with the lowest kinematic viscosity, and mid or low saps..

- Low kinematic viscosity ("weight" -- i.e. xw-30, xw-40, etc.)
- High viscosity index
- High HTHS viscosity
- High flash point
- Low volatility [NOACK thanks for the explanation]

"Switching oils can cause higher-than-normal oil consumption, so at this point you have no way to tell what you're dealing with. Stick with one oil (make it low-SAPS if you want, but make SURE it meets the specs in your owner's manual) for at least three oil changes"

I had no idea that switching oils coul increase oil consumption (!)

d00df00d, considering that i have to top up every 600 to 720 miles, by "three oil changes" exactly after i how many miles do you think i should run the same oil?

Thank you everyone.

 

[d00df00d]

What's the factory recommended oil change interval?

 

[FL_Rob]

He's in the 'perpetual oil change' mode right now ,adding more to top up than the factory oci.Tuga,the Helix ?w30 is fine just stick with it, no additives, and let it take a 'set' to become balanced and add the same to top up,it;s all you can do until repair time.

 

[expat]

Have you considered a Piston soak?

 

[mechtech2]

That compression is WAY too high. I suspect an advanced intake cam, or possibly a LOT of carbon and other combustion chamber deposits.
Check these things first.
With less compression, your oil control may become more normal.
Also, carbon on the ring/piston lands will make them not work right.
And of course your PCV [Positive Crankcase Ventilation] system must be perfect.

 

[TugaSaudade]

As far as OCI's go, VW states up to 18.000miles with a VW503.01 or VW50400 spec oil
(Pennzoil Ultra 5w40 could go that far.. if i had NO oil consumption)

Up to 9000 miles with a good VW50200 spec oil and up to 6000 miles with a above average VW50101 semi-synth or high quality mineral oil..

Talked to the mechanic about a piston soak but he said that if the high values from the compression test were caused by oil that passed to the combustion chamber, it wouldn't be a reliable test, neither a leak down test..

Solution presented to me? Spend 1000 bucks tearing the engine, JUST TO SEE if it was piston ring failure.. or go to a perpetual oil change mode with the cheapest oil i could find until the engine explodes.. because everyone here were i live keeps saying that its "normal" in this engine.. used by VW in the VW Polo, Audi A2, VW Golf and Skoda Fabia..

Thing is, i spent every cent i had in March this year just to buy the car..

So i prefer trying to delay the so called "engine blow up" by doing damage control with the best oil that is able to keep the engine within repairing condition before it goes beyond that.. if the 2 cats hold 'til then..

So, Helix xW30.. Ultra or something else?
Is it worth buying a PAO?
Will a mid or low saps make any real difference delaying cat failure?

I see there is no "cheap" solution so i'm going to ask the local VW dealer how much they charge to replace the PCV valve, just to be on the safe side.. either that or set up a catch oil canister to see if it buils up there..

Anyway, its time to buy some more oil..

 

[hooligan24]

seafoam piston soak to free up the rings

 

[FL_Rob]

Let me ask you, how long does it take to go the 600 to 750miles to use a quart of oil? The next is a statement.If youre not billowing clouds of oil smoke and its definitely not leaking AND we know VW's notoriously use oil,then Seafoam the rings (or equivalent in your area)see if it helps, add the oil ,keep adding oil.Your engine wont blow up unlees you over rev it, overheat it or do something harsh during operation.You're not rally racing are you?,ok then.No rods knocking?,ok.No coolant loss into the oil?ok.Add oil and drive .