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I have a 2004 Infiniti G35 6MT coupe. Nissan VQ35DE engine with a bit over 156,000 KMs (about 96,000 miles). Since I bought it, I've noticed some oil consumption at a rate of about a litre every 4,000 KMs (about a quart every 2,400 miles). There's no smoke of any kind from the exhaust or anywhere else, there are no puddles on the floor. I changed the PCV valve about 200KMs ago, that doesn't seem to have made any difference.

I put in Mobil1 5w30 synthetic on the first change, changed to Castrol Edge 0w30 A3/B4 at my most recent OCI (supposedly a "heavier" 30). I plan to try either a high mileage full synthetic or 40 weight synthetic next. I'm debating whether it's worthwhile to just empty my oil with only 1000KMs on it and fill with one of those replacements now or wait until my next OCI.

Other than that, the engine runs perfectly. No sputtering, no rough idling, no power loss, no codes, no dash lights, nothing.

Some relevant information:

Measurement Method

When I take and record oil measurements, the car is parked the same spot and the engine is fully cooled (ie.: >= 12 hours) each time. I use a ruler to measure the millimeters between the H mark and the oil level on the dipstick. This is the officially recommended measurement procedure according to Nissan's TSB on the later VQ35HR models to gauge oil consumption.

Driving Habits and Environment

I didn't buy a 6-speed manual coupe to drive it like a grandma to the shops, so yes, it gets a bit of a workout. But I'm always sure to let it get up to temperature and be there for at least a few minutes before any of that, and I tend to keep it under 5,000 RPM, rarely up the redline (~7000 RPM). Otherwise, it's light throttle and under 2500 RPM.

It does get winter driven (Canadian winters), but it has a block heater I generally keep at low RPMs in winter because of the extended warm-up time. Winter time also involves a lot more idling.

Questions:

  • Obviously: what else can I try to reduce the consumption rate?
  • As long as regularly ensure a correct oil level by checking and filling it when needed, how harmful is it to the engine and how does it affect longevity?
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  • Hello, and welcome to the site! I also have a 6mt G35 ('06 sedan), which I am very much in love with. I'm pretty sure the '04 didn't come with the rev-up engine, but I think it's worth pulling your coils and checking the spark plug wells for oil. Leaky cam cover gaskets were a common problem on the 05-06 G.
    – MooseLucifer
    Commented Jul 2, 2016 at 16:40
  • @MooseLucifer: indeed, the '04 did not have the HR engine, but many are still known for oil consumption. I'll check the plugs to see what they look like.
    – autobottodoggo
    Commented Jul 2, 2016 at 16:50
  • Just FYI: HR and Rev-up are different, VQ35 DE with the 'rev-up' package added variable timing on the exhaust cam (regular VQ only has VVT on intake), and raised the redline to 7500. VQ35HR went to dual intake/TB, entirely new plenum design, and a bunch of other changes.
    – MooseLucifer
    Commented Jul 2, 2016 at 16:56
  • @MooseLucifer: good to know, thanks. In either case, it's an '04, so it's neither HR nor rev-up.
    – autobottodoggo
    Commented Jul 2, 2016 at 17:40
  • I did hear of the G35 oil burning problem recently. There is a forum on it on carproblemzoo.com/infiniti/g35/engine-burning-oil-problems.php I think that there was a recall about this issue.
    – wilkvolk
    Commented Aug 14, 2020 at 23:36

1 Answer 1

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The oil can't disappear without a trace, its either leaking somewhere or its leaking and being consumed.

You say there is no evidence of leaks (no puddles on the floor) and you also say there isn't any smoke from the exhaust or elsewhere.

Even though you say there is no smoke from the exhaust, this engine is known for piston ring issues and early wearing. Its the most likely cause of the oil consumption. It may be that they are worn enough to let a decent amount of oil past but not yet worn to the extent that the rate of oil volume burned is enough to create a conspicuous amount of smoke.

So you asked the question 4 years ago, did you find out what the issue was?

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  • I actually sold that car a couple of years ago. I think I just ultimately accepted it was more-or-less normal for the car, since it's such a commonly-reported thing.
    – autobottodoggo
    Commented Jun 17, 2021 at 15:32
  • @autobottodoggo It was relatively common but I owned two G35's and didn't have that issue. Was just bad luck for you I think.
    – NetServOps
    Commented Jun 17, 2021 at 23:31

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