Oil consumption Non Linear?

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Originally Posted By: zoomzoom
Originally Posted By: qship1996
I have noticed something I find baffling....on my 96 Q45 oil consumption is not linear at all- for instance on a fresh fill of Redline 0w-30 oil is 11 ounces low after 2300 miles of use{which I measure and refill} then the next 1000 miles of driving consume 15 ounces....driving pattern is identical which consists of a 120 mile daily roundtrip all highway at speeds of 80-95mph. This pattern has been similar for almost every oil change interval,any ideas????


try their 10w-30 and report back



Behaves the same with 5w-30, 10w-30, 10w-40 Redline oil.
 
It is not oil fatigue based on multiple fantastic oil analysis results

Maybe initial fill when performing the oil change is slightly overfilled making me think the initial usage is less than later measurments? I will double check the level on dipstick after next oil change- capacity is listed in manual as 6 quarts and that is what I dump in every oil change.
 
Originally Posted By: ottotheclown
Switch to GTX asap, you were a victim of bovine poop at $9.95 a quart.


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I would switch to a less expensive 10w30 dino name brand like PYB, QS green, Valvoline and see what happens. Redline is too expensive to blow on that car. The mid 90's Q45's were notorius for failing fuel injectors which is probably your issue. I had a 95. It was the worst lemon I have ever owned. It was at the dealer 37 times in a 48 month lease. When I took it in for repair at 50k the service manager told me to not drive it beyond the 60,000 mile bumper2bumper warranty because the fuel injectors usually never made it to 70k. When I told him it was a lease he said "Lucky You". I drove it to 59,950 miles it and parked it for the last 30 days so it was under warranty when I turned it in.
 
Originally Posted By: PT1
I would switch to a less expensive 10w30 dino name brand like PYB, QS green, Valvoline and see what happens. Redline is too expensive to blow on that car. The mid 90's Q45's were notorius for failing fuel injectors which is probably your issue. I had a 95. It was the worst lemon I have ever owned. It was at the dealer 37 times in a 48 month lease. When I took it in for repair at 50k the service manager told me to not drive it beyond the 60,000 mile bumper2bumper warranty because the fuel injectors usually never made it to 70k. When I told him it was a lease he said "Lucky You". I drove it to 59,950 miles it and parked it for the last 30 days so it was under warranty when I turned it in.



Sorry to hear you had a lemon....I have owned my Q since new,and currently have over 240,000 wonderful miles on it with very little problems....in my 32 years of driving , it is the best, most reliable car I have owned and still quite a pleasure to drive. Please explain how you think faulty fuel injectors could lead to non linear oil consumption........ ps I am still on factory installed fuel injectors which are operating perfectly at 240,000 miles.
 
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Armchair mechanics :)

Engines can consume more oil at a high rpm extended freeway drive..

are you over 3k rpm for extended periods?
 
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Originally Posted By: qship1996

Please explain how you think faulty fuel injectors could lead to non linear oil consumption........


Easy, faulty fuel injectors/fuel rail/presure regulator can leak fuel into the sump. As the percentage of fuel dilution increases throughout your OCI it begins to dilute the oil and subsequently increases the volatility of the oil in the sump causing it to oxidize and burn off at a faster rate. The longer and more the fuel leaks into the sump the higher the volatility of the mixture and the higher the rate of oxidation.
 
Originally Posted By: Rand
Armchair mechanics :)

Engines can consume more oil at a high rpm extended freeway drive..

are you over 3k rpm for extended periods?


That alone would not cause non-linear consumption. Consumption, surely, but if it's flying out the PCV, without some degradation, there's no reason for it to fly out faster.
 
Originally Posted By: PT1
Originally Posted By: qship1996

Please explain how you think faulty fuel injectors could lead to non linear oil consumption........


Easy, faulty fuel injectors/fuel rail/presure regulator can leak fuel into the sump. As the percentage of fuel dilution increases throughout your OCI it begins to dilute the oil and subsequently increases the volatility of the oil in the sump causing it to oxidize and burn off at a faster rate. The longer and more the fuel leaks into the sump the higher the volatility of the mixture and the higher the rate of oxidation.


Let me spin it up differently. He is consuming in a linear manner but the fuel additions are flashing off what can be flashed off (allegedly 50%) and the remaining, more stubborn and less volatile, stuff is taking up space. The volatility of the oil can be unchanged.
 
Originally Posted By: Gary Allan
Originally Posted By: PT1
Originally Posted By: qship1996

Please explain how you think faulty fuel injectors could lead to non linear oil consumption........


Easy, faulty fuel injectors/fuel rail/presure regulator can leak fuel into the sump. As the percentage of fuel dilution increases throughout your OCI it begins to dilute the oil and subsequently increases the volatility of the oil in the sump causing it to oxidize and burn off at a faster rate. The longer and more the fuel leaks into the sump the higher the volatility of the mixture and the higher the rate of oxidation.


Let me spin it up differently. He is consuming in a linear manner but the fuel additions are flashing off what can be flashed off (allegedly 50%) and the remaining, more stubborn and less volatile, stuff is taking up space. The volatility of the oil can be unchanged.


yeah...that's it...exactly what I meant.
 
Originally Posted By: Gary Allan
Quote:
It is not oil fatigue based on multiple fantastic oil analysis results


Well, can someone check my math here .. This UOA shows that your fantastic results went from 10.7 to 13.5 cSt during this OCI

PT1 may have a better spin than I thought.


Get an oxidation and nitration reading next time (use another lab).


The thickening is all of the junk left over that won't easily flash off as the fuel/oil mixture oxidizes? I would do a UOA at about 2000 miles and check for % of fuel dilution that is present right before the linear curve falls off.
 
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Well, the stuff is thickening. Amsoil used to USE this to their advantage with the TSO.

The thing is that it shouldn't increase in consumption. If anything I'd expect it to slow up.

So ..where are we at? Who knows? Maybe his suggestion that he over filled to begin with is the most informative part of this post
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That was an old, old oil analysis{performed 90,000 miles ago} the recent ones are showing viscosity staying in spec and fuel dilution of less than 1/2 of 1 percent.Terry Dyson worked with me on the first analysis and suggested methods to improve the numbers and after following his advice the last 3-4 years worth of tests have come out excellent, including the last one performed 7 weeks ago-I remain puzzled but am leaning towards the initial refill after a oil change may be slightly overfilled causing the initial drop on the dipstick to take more miles to show up than subsequent checks.Guess I shouldnt complain about needing to add 1.5 quarts makeup oil on a 6500 mile oci on a 240,000 mile old engine?????
 
It's the only one you posted
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Does it still thicken? While I can see tweaks here and there, I don't think you'll change the characteristics of the oil. Naturally Terry may have you using LC or something like that.
 
No longer thickens, most recent UOA showed less than 1/2% fuel, 400F flashpoint,low silicon....overall an excellent report????
 
I'd probably say "YES" ..but since we haven't seen the whole report, I'll take your word for it. It would kinda require either some change in the engine, the oil formulation, or an additive.

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Redline could have changed their formulation in that time. Amsoil did with the SSO.
 
Originally Posted By: qship1996
Guess I shouldnt complain about needing to add 1.5 quarts makeup oil on a 6500 mile oci on a 240,000 mile old engine?????


I wouldn't complain. Especially if the fuel system is ok. I would write that off as an age issue. I would probably switch to a less expensive oil and go 5000 and see what happens.
 
I have enough Redline oil stocked to last til I retire the Q in 2011!!!!
 
I had a BMW that was like this.
Not much oil use until 2k on the oil - then she would start using it fast.
I assume the oil was getting sheared - possible beat up in other ways from blow by and fuel.
 
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