Sudden Oil Consumption?

[thescreensavers]

My engine(VQ35DE) has always used around 1/4 quart for every 5k (Syntec 5W/30)

Recently PU was on sale and I tried it. After 1k miles I was down half a quart, topped it off and not thinking much about it I switched to M1 0W-40 and it got worse, in 2k miles I have had to top it off with some 5W-30 GTX (was on the road)

I just changed it out and put in some GTX 10W30 to see how it goes.

Whats also odd is my MPG has also tanked, its about halved.

I guess the next step is to check the plugs and do a compression test. Would an MMO piston Soak be beneficial?

I checked my PCV valve and compared it with ones at the store, the check ball still sounded like the new ones, so I assume it still works, though I might just replace it.

 

[Scott_Tucker]

Compression and leakdown wont tell you anything about an oil consumption problem unless the engine is running rough. Hows the car running?

 

[provels]

Don't know what mileage you're at, but the VQ35 in my FX35 began leaking at the gasket behind the oil cooler that the filter mounts to. Common problem. Replaced it, leaked after a while, then replaced it again with a redesigned part. Left very little evidence on the garage floor. Oil was off the end of the stick when I caught it. Now I burn a quart in 1K miles @ 170K miles, oh well. Here's a link.

http://www.infinitiscene.com/forum/threads/13716-Oil-Cooler-DIY

Just noticed the part about mileage. Fuel sensors have issues, too. Just throwin' it out there.

http://www.infinitiscene.com/forum/threads/13056-Gas-Gauge-Level-Fix

 

[mechtech2]

You are using 5 times the oil you normally do, and are using twice as much fuel.
There have to be symptoms commensurate with these things.

 

[IndyIan]

Is your car one of the ones that sucks bits of catalytic conveter into the motor? Read up on it atleast...

 

[provels]

Originally Posted By: thescreensavers
I checked my PCV valve and compared it with ones at the store, the check ball still sounded like the new ones, so I assume it still works, though I might just replace it.

I went that route, too, but no better. I don't know if your engine is inline or transverse, but if you can cup the oil cooler with your hand(when it's cold, please) and come back with a handful....

 

[thescreensavers]

Originally Posted By: Scott_Tucker
Compression and leakdown wont tell you anything about an oil consumption problem unless the engine is running rough. Hows the car running?


Hmm I thought compression test would tell me if the rings are bad? It says in the service Manuel to do that? Also if it fails to put some oil into the cylinder to see if it goes into spec which says the rings are bad?

Car Runs fine, there is a small stutter/hesitation issue but I believe its ECU related as I can repeat it reliably, no other problems other then disappearing oil and now gas.

my MPG dropped on the way back home from NC(Deals Gap) it was 16mpg lowest I have ever seen. I reset my ECU and popped back up to 24 which is a little on the low side(car is not stock though) But now the MPG drop popped up again.

Originally Posted By: provels
Don't know what mileage you're at, but the VQ35 in my FX35 began leaking at the gasket behind the oil cooler that the filter mounts to. Common problem. Replaced it, leaked after a while, then replaced it again with a redesigned part. Left very little evidence on the garage floor. Oil was off the end of the stick when I caught it. Now I burn a quart in 1K miles @ 170K miles, oh well. Here's a link.

http://www.infinitiscene.com/forum/threads/13716-Oil-Cooler-DIY

Just noticed the part about mileage. Fuel sensors have issues, too. Just throwin' it out there.

http://www.infinitiscene.com/forum/threads/13056-Gas-Gauge-Level-Fix



I just hit 80k, I know about the gas gauge issue but that is not the issue here, I have actually had the MPG drop sharply I reset the ECU and it went about back to normal. (I go by gallons filled and miles driven) But I know how many miles I should hit per marker(3/4,1/2 a tank) on the gauge.

Now the Oil cooler, I checked and there is no oil leaking from there at all the bottom is all clean and dry, no blue smoke nada. I went with GTX since its not Synthetic it should show some smoke hopefully.

I also Park in a garage with white floor, I have intentionally left my under tray off so I can see drips or what not, but so far its dry nothing on the floor.

Originally Posted By: mechtech2
You are using 5 times the oil you normally do, and are using twice as much fuel.
There have to be symptoms commensurate with these things.


Yea, I agree. But honestly if you would of driven my car a few months ago to now there is no difference at all. I know my car pretty well and it frequents redline.

Originally Posted By: IndyIan
Is your car one of the ones that sucks bits of catalytic conveter into the motor? Read up on it atleast...


Nope, have not heard of that issue on my car, I have heard a theory that Test Pipes causing lack of back pressure causing OC. But not broken cats.

Originally Posted By: provels

I went that route, too, but no better. I don't know if your engine is inline or transverse, but if you can cup the oil cooler with your hand(when it's cold, please) and come back with a handful....


Its a G35 so its Longitudinal, I have felt around the oil cooler and got some white paper towels but no dice no leakage.


My mileage has dropped so that is what I think its interfering with combustion... but I am not sure.

I honestly have no idea what else to do other then to take apart the intake, look at the plugs and do a compression test.

 

[Scott_Tucker]

Originally Posted By: thescreensavers
Originally Posted By: Scott_Tucker
Compression and leakdown wont tell you anything about an oil consumption problem unless the engine is running rough. Hows the car running?


Hmm I thought compression test would tell me if the rings are bad? It says in the service Manuel to do that? Also if it fails to put some oil into the cylinder to see if it goes into spec which says the rings are bad?



Service manual is absolutely wrong. Well, as far as oil consumption is concerned. The compression and leakdown will tell you the condition of the compression rings only. It will tell you nothing about the oil control rings, and thus will tell you nothing about your oil consumption problem. The oil rings don't seal compression so won't show up on a compression test. The valve guide seals aren't in the combustion chamber so that doesn't show up either.

Compression test for an oil consumption problem is one of those myths that has spread across the internet like wildfire. It makes me wonder how many people have thought their oil control rings were good because they got good results from the test. However, if your engine is running rough and it has low compression that is a different story, but if that is the case, you have bigger problem.

 

[thescreensavers]

Originally Posted By: Scott_Tucker
Originally Posted By: thescreensavers
Originally Posted By: Scott_Tucker
Compression and leakdown wont tell you anything about an oil consumption problem unless the engine is running rough. Hows the car running?


Hmm I thought compression test would tell me if the rings are bad? It says in the service Manuel to do that? Also if it fails to put some oil into the cylinder to see if it goes into spec which says the rings are bad?



Service manual is absolutely wrong. Well, as far as oil consumption is concerned. The compression and leakdown will tell you the condition of the compression rings only. It will tell you nothing about the oil control rings, and thus will tell you nothing about your oil consumption problem. The oil rings don't seal compression so won't show up on a compression test. The valve guide seals aren't in the combustion chamber so that doesn't show up either.

Compression test for an oil consumption problem is one of those myths that has spread across the internet like wildfire. It makes me wonder how many people have thought their oil control rings were good because they got good results from the test. However, if your engine is running rough and it has low compression that is a different story, but if that is the case, you have bigger problem.


So then what should I do? I am loosing oil some where?

 

[OVERKILL]

Oil chemistry changes (changing brands) can cause consumption spikes that then go away after the oil "settles in".

 

[dave1251]

I have a suggestion use a high ester oil such has Red Line for a OCI or two. My theory is that the high ester content will safely clean out the inside of your engine, this in theory will lower your consumption. This is after you have used the same oil for at least two OCI's I have seen and heard after changing brands with different chemistry although compatible sometimes oil consumption is increased.

 

[KrisZ]

Originally Posted By: thescreensavers
So then what should I do? I am loosing oil some where?


For starters, have someone start the car, after it sat all night, and you watch the tail pipe for blue-ish smoke, it may be a brief puff of smoke as well. Also once the car is warmed up, leave it idling for a minute or two and then blip the throttle to 2-2.5k RPM and watch for the smoke again. You can examine your tail pipe for oily residue and excessive soot. You can check the coolant reservoir for oil signs, and lastly get the car on ramps and check all underside for oil leakage. That includes the engine, suspension and car's body. Just because you don't see oil on the ground doesn't mean there are no leaks.

 

[thescreensavers]

Originally Posted By: KrisZ
Originally Posted By: thescreensavers
So then what should I do? I am loosing oil some where?


For starters, have someone start the car, after it sat all night, and you watch the tail pipe for blue-ish smoke, it may be a brief puff of smoke as well. Also once the car is warmed up, leave it idling for a minute or two and then blip the throttle to 2-2.5k RPM and watch for the smoke again. You can examine your tail pipe for oily residue and excessive soot. You can check the coolant reservoir for oil signs, and lastly get the car on ramps and check all underside for oil leakage. That includes the engine, suspension and car's body. Just because you don't see oil on the ground doesn't mean there are no leaks.


No Blue smoke, No oily residue on exhaust, I have checked all around the engine bay ontop and under nothing has oil on it.

My Coolant reservoir has no milky looking coolant, just a bit darker then new as It was change 40k miles ago, its due for a changing soon.

I have all the tools and supplies to pull plugs and do a compression test as well as take apart the intake. Ill see what happens after that

 

[thescreensavers]

So some updates,

Intake looked normal, but smelled of oil, I have installed a PCV catch can and bought a new PCV Valve.

I pulled my plugs and and made a thread about it.

It was a toss up between Normal,Running lean or burning some additive in the gas I use, Or Oil burning.

There was no oil pooling with my spark plugs. I did not get to do a compression test.


I have been running Castrol GTX 10W30 and Consumption slowed thankfully to a more manageable 1 quart/2k miles. Though that is still way more than it did 5-10k miles ago.

Should I keep with GTX 10W30 or Switch back to Syntec since I was using for mostly every oil change? Should I try a piston soak? I am still not really sure why I am burning oil.

 

[steve20]

sounds like your consumption started a few thousand mile after the tune--correct? If so, that is your answer-ran lean/hot and caused mechanical wear--->oil consumption.