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Where does the oil go?


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I notice over time my S30 uses a couple quarts of oil between changes. Conventional oil seems to go quicker so last change I used Mobil 1 and it seems to do better with that. No visible leaks or smoke, just loses oil over time--so, where does it go?

 

I don't think it's age related as the mechanic that works on my cars has a fairly new big SUV and it does the same thing. He was working on my car assessing a new whining noise coming from the engine we suspect is the oil pump (also low pressure) when he said he had to add two quarts as it was barely touching the stick; however, I had checked it prior to taking it to him (car sat for a couple days) and it was full (H).

 

Just curious...

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If you have a malfunctioning air regulator, the oil will be pulled up out of the breather tube in the valve cover where it will travel down your air tubes for insertion into your throttle body where it will be blown back into your engine for combustion...

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Smoke is solid particles. Cat does not stop them. You cant burn smoke, it has already burnt. 99% of the cars going down the road burning oil have working cats.

 

Grandma had a 93 lebaron with that shitty 3.0 by mitsubishi. Smoked like CRAZY, passed emissions with flying colors. No body ever thought it would pass but it did every time lol.

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How much are you using per oil change? You are probably just getting blow by. The oil is getting past the rings as you drive, but it is so little that you don't "see" smoke. My Maxima does the same thing, but it looses a quart in 7500 miles, which you would never be able to see. Don't worry it's not a big thing. The Z06 Corvettes had this problem the first year because of weak rings. Most guys just deal with it and check the oil that more often. Hope this helps.

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Old engines like thick oil. On old engines I run 20 50 oil. Had a Blazer years back use 10 40 and went through a quart every 1000 miles, 20 50 every 3000 miles or ever oil change. This was probibly due to valve seals on that engine.

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How many miles on your engine and how do you drive it (fast, normal or ab-normal), highway, in town, a lot of turning it off and starting it and do you like reving the engine? A compression test would give you a general idea of the condition of your rings. My money is your cylinder pressure is down and it's being burnt.

 

:wink:

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How many miles on your engine and how do you drive it (fast, normal or ab-normal), highway, in town, a lot of turning it off and starting it and do you like reving the engine? A compression test would give you a general idea of the condition of your rings. My money is your cylinder pressure is down and it's being burnt.

 

:wink:

 

130K driven like it was meant, fast around town (35-45 zone); 14 mi one-way to work thru downtown w/ ~ 10 lights and a long stretch of parkway @ 45+. I don't rev the engine; I don't need to as it purrs like a kitten and roars like a tiger--only thought that was necessary to keep a poor running engine from stalling :wink:. I need to change the plugs so I'll buy a gauge while I'm at it and check all the cylinders.

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I need to change the plugs so I'll buy a gauge while I'm at it and check all the cylinders.

 

Here are the results of the compression test:

 

1. 138 psi

2. 137 psi

3. 132 psi

4. 137 psi

5. 130 psi

6. 128 psi

 

The plugs look normal on all cylinders with exception to 5 & 6 had (wet) oil residue around the threads at the base of the plug and the seats on the block; however, the plugs were not oil fouled. So, I may have some blow-by.

 

A couple weeks ago the engine started making a subtle 'whine' similar to a noisy automatic transmission and I noticed my oil pressure had dropped considerably (in half). With a manual gauge screwed in, the engine produces 0-18 at idle/stoplight, and ~30 to 45 under power (and at higher revs). Prior to all this, oil pressure was consistently in the 70-80 range on my interior gauge; however, at a stoplight or idle would fall to ~30-45 psi.

 

The mechanic that usually works on my car suspects the oil pump is bad. What other things should I look for to pinpoint my problem or confirm this? Otherwise, the car still runs good/strong and has smooth idle but I'm afraid to drive it with the low oil pressure and the subtle whining. There is no visible smoke or burnt oil smell coming from the car.

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Can you hear the whine under the hood?

Or just under a load when driving?

 

Yeah, you can hear it under the hood and seems to be coming from the top of the engine; however, the mechanic I had look at it suspects it's coming from the lower part of the motor. It's difficult to pinpoint due to the resonance from all the metal-to-metal parts. Also, the trans/shifter feels a bit different as if a little 'dry' and stiff.

 

You don 't hear the whine after initial start up; just after a few minutes when the engine is warm and you rev it a couple times the noise appears and stays.

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