Excessive Oil Consumption

[Dan Q]

After driving my '05 G35 Sedan 6MT for 2900 miles, it began to make a sound sort of like a diesel engine although not as loud. It sounded like a rough idle, but it occurred when shifting into or out of gear or laying into or off of the throttle. The service engine soon light also came on. I brought it into the dealer and after much investigation they "identified" the problem as a clogged valve in the variable valve timing system. Due to the engine being partially disassembled for a couple of days they also drained and refilled the oil in the event that debris mad its way into the engine. This satisfied the computer and a reset got rid of the light. They were unable to recreate the noise and assumed it was fixed.

At 5200 miles the noise came back. They took the vvt system back apart and found a chain pin that was not removed from some part of the vvt assembly. They also happened to give me my first scheduled oil change. The noise was gone upon reassembly.

Last week at 8200 miles the noise came back. I scheduled to bring it in and in the interim, the oil light came on during a hard stop. I checked the oil and it was not registering on the dipstick. 4(!) quarts brought it up to between mid and full. A reasonably intelligent person would assume that this has been the problem all along, but Infiniti is doubting that. I am currently in the process of running an oil consumption test on the car for them. Given the history, the car seems to be burning ~1.5 qt/1000 miles. There is no oil in the coolant, no drips in the garage, and no smoke coming from the tail pipe. Where is the oil going? When it inevitably comes to replacing the engine after I complete their test (a minimum of two times), is a long block an adequate fix for the problem? What would you do if you were in my situation?

Thanks in advance for your opinions on this, and sorry for the long winded question. I will be posting the outcome of my problem when it gets resolved, but it will be another 1800 miles before I complete the two oil consumption tests that Infiniti is requesting.

[szh]

That is way too high an oil consumption. I would push Infiniti for a new engine!

Z

[rydwhite]

Strange. I haven't heard of this problem with any other G35.

[szh]

Strange. I haven't heard of this problem with any other G35.

One fluke for sure, I suspect!

The 2003/2004 M45 and Q45 engines are a different story. There, good break-in procedures are required to prevent excess oil use ... I use about a half-quart halfway between oil changes (3750 miles), and that is a good result.

Z

[steve s14]

my sister's 05 g35 sedan is burning 1.8 qts/ 1000 miles. i heard that this is becoming a problem that is surfacing. dan Q did you get any word on what infiniti will do for you yet?i'll see if they will do anything about my sisters car, it's at the dealership now and shes in a loaner car for now.

[rydwhite]

Check out Dan's update post zerothread?id=144227

It's a shame he was treated this way. I haven't heard of too many really bad complaints about Infinti service, but this happened to be one.

Since, it sounds like this is becoming a more prevalane issue, maybe Infinti is going to taking better care of their customers with this.

I'm really interested to hear what the dealer says about this. Definetly post up an update.

[steve s14]

well, they said that they are going to do a compression test and a leak down test. that's the last piece of information that i got from my sister. they sure are taking their sweet time!!!, it's been over a week now. once i find out anymore info on their findings, i'll post it.

[rydwhite]

Hey Steve, thanks for the update. Hopefully things will get taken care if in a more timely manner once they have conduct the leak down and compression tests.

[Q45tech]

Higher oil consumption [than people were use to] has always occured with the 3.5. What happens when you exceed the theoretical 3.00 liter optimum size for a V6 and try to maximize power output with low tension rings to reduce friction.

Why you are supposed to check oil level every weekand add as necessary.

[steve s14]

after the dealer did a compression test and a leak down test, they told my sister that they are going to replace the engine.i think they are going to put a long block in it.it just sucks that the car only has 6000 miles on it and is already in need of an engine replacement.2qts per 1000 miles, thats just plain rediculous. i hope it fixes the problem because the compression readings and leak down numbers don't sound like it would consume that much oil but who knows, i guess we'll see when the car gets it's new engine.

[szh]

2 qts per 1000 miles is, indeed, ridiculous! I am glad that they are going to replace the engine. Rare event, but it will come out right for you, despite the pain of having to get it done.

As an aside, I recommend a good engine break-in regimen, with oil and filter changes, to get it right for the future.

I.e., change oil and filter (with a good dino oil, not synthetic) at 200 miles, 1500 miles and then every 3750 miles from then on. Consider switching to synthetic oil past 10,000 to 15,000 miles (but this is not an essential step as long as you use good dino oil and are rigorous about changing oil and filter regularly) and you should be in good shape for the future.

Z