Advice for next oil change on '04 Infiniti G35.

[OCDriver]

Originally Posted By: il_signore97
As for short trips (that you said in a post further down), there are two schools of thought. You can go thinner (30 grade) and get some fuel economy benefit due to the fact that your oil won't be warmed up fully, and you will be wasting power shearing the thick oil in your engine bearings. However, the other train of thought is that because you're short tripping in cold weather, your engine will most likely be running rich (excess fuel for proper combustion) for a fair amount of time. This dilutes the oil and thins it out over your change interval, and reduces its viscosity. It may or may not be a problem, but one easy way to counter this is to go up to a 40 grade. It could be thicker than necessary, but thicker will never hurt an engine, just waste a bit more fuel, that's all.


With the limited mileage I accrue yearly, cost of oil and fuel is of such negligible consequence to me.

Taking money completely out of the equation and considering only the engine longevity, performance and conditioning, it sounds like a 40 will best suit my needs? Or maybe somewhere in between with a typically "lighter" 40 or "heavier" 30.

 

[il_signore97]

Originally Posted By: OCDriver


With the limited mileage I accrue yearly, cost of oil and fuel is of such negligible consequence to me.

Taking money completely out of the equation and considering only the engine longevity, performance and conditioning, it sounds like a 40 will best suit my needs? Or maybe somewhere in between with a typically "lighter" 40 or "heavier" 30.



It's really hard to say with any certainty. I doubt you or anyone else on here (despite what some may claim) would ever be able to put this argument to rest definitively. It takes tons of R&D time and money and lots of repetitive trials to determine something like this. So that leaves us with making an educated guess.

All I can say is that you don't need to worry about "thick" or "thin" 40's / 30's, etc. Nissan formally allows 40 grades for this engine in the owner's manual, and it doesn't say "thin" 40's only!

When I had a VQ engine... I ran many different grades (0W30, 5W30, 5W40, but mostly 0W40). I had no issues whatsoever, winter or summer. Mine was sold with about 250,000 km on it with no internal or external engine work. I did however get rid of the ceramic pre-cats early on as those were known to disintegrate and get sucked back into the engine, thus destroying the rings. I replaced them with high flow metal core units.

Just to give you a different example: My present car (Benz in my signature) requires a certified Benz oil, of which M1 0W40 or Castrol 0W40 meet those requirements and are most easily obtainable for me (and most other people that drive similar vehicles). Think about all of these cars that do short trips and/or live in cold climates (mine spends plenty of time on trips up north during the winter and starts fine without using the block heater in -30 to -35 C with 0W40). If it were a problem, we would have found out by now! In my opinion, Benz and other Euro makes specify grades like 0W40 on their approved lists to attempt to cover all climate extremes with the least amount of customer intervention or decision-making. It's working I'd say.


Originally Posted By: dtownfb
Keep an eye on the oil level. Running these engines on low oil will stress the timing chain.


This is great advice here. Maybe even more important than oil selection in my opinion. These engines are hard on timing chains / tensioners / guides.

 

[OCDriver]

Quote:
I did however get rid of the ceramic pre-cats early on as those were known to disintegrate and get sucked back into the engine, thus destroying the rings

Alrighty then... getting rid of those ASAP!

Quote:
Keep an eye on the oil level. Running these engines on low oil will stress the timing chain.


Absolutely. I check it several times a week.

 

[bbhero]

il signore your advice is the best I've seen on here when it comes to these VQ motors. Outstandingly well done sir.

 

[artificialist]

Originally Posted By: OCDriver
Quote:
I did however get rid of the ceramic pre-cats early on as those were known to disintegrate and get sucked back into the engine, thus destroying the rings

Alrighty then... getting rid of those ASAP!

Quote:
Keep an eye on the oil level. Running these engines on low oil will stress the timing chain.


Absolutely. I check it several times a week.


It may be illegal to remove the pre-cats where you live. Some places enforce the smog laws, some don't. You may also get a check engine light.

 

[OCDriver]

I meant replacing them with something better.

So, I've been looking up a bunch of oils and numbers. Putting it simplistically, a higher HTHS would generally mean less potential burn-off?

 

[slacktide_bitog]

Castrol 0w30 is popular on the G35 and other Nissan VQ engines

 

[bbhero]

I got 10qts of the Castrol 0w30 as it was on clearance at AAP.... It does run very well in my Altima 3.5.

 

[Garak]

Originally Posted By: OCDriver
Putting it simplistically, a higher HTHS would generally mean less potential burn-off?

il_signore gave a great writeup. And yes, that may be the case. Of course, in practice, one never knows, and sometimes things take some experimentation. Unfortunately, patience is the key.

 

[il_signore97]

Originally Posted By: OCDriver
Originally Posted By: il_signore97
I did however get rid of the ceramic pre-cats early on as those were known to disintegrate and get sucked back into the engine, thus destroying the rings

Alrighty then... getting rid of those ASAP!


Just a thought... Before you bite the bullet on replacing those precats with aftermarket metal core units, you may want to browse your vehicle-specific forums to see whether or not it's a problem in the Infinity RWD platforms. I know that this issue was very prevalent on all FWD VQ35 (and QR25) engined platforms due to precat placement (far too close to the exhaust header). The proximity to the exhaust header is what allowed the disintegrated precat material to be sucked back into any cylinder that was experiencing a "back-pulse" due to intentional valve overlap using the VVT system. This was done to eliminate the need for a dedicated EGR valve on these engines. Your RWD Infinity may have the precats far enough away that they would just send crumbled material out of the exhaust and eventually throw a CEL to let you know when they don't function anymore (which of course poses no risk to your engine).


Originally Posted By: bbhero

il signore your advice is the best I've seen on here when it comes to these VQ motors. Outstandingly well done sir.


Thank you! I've done more work to my VQ-engined Altima than I care to remember (and all on my back to boot)! Whatever info I can share to help a fellow VQ owner get more enjoyment out of their vehicle is the least I can do

Originally Posted By: OCDriver
So, I've been looking up a bunch of oils and numbers. Putting it simplistically, a higher HTHS would generally mean less potential burn-off?


As Garak said, you can potentially get less burning, but not necessarily (depending on the mechanism of oil use, your vehicle, your driving, your environment, etc). You have nothing to loose in trying something different. If nothing changes, you would have at the very least accomplished an oil change that was necessary anyway!!! lol

 

[mclasser]

M1 0W40 does a good job curbing consumption in my VQ35.

 

[OCDriver]

Quote:
il signore your advice is the best I've seen on here when it comes to these VQ motors. Outstandingly well done sir.


I'll second that! That post give me a big leg-up on learning how to a lot of the important technical specifications.

Quote:
Just a thought... Before you bite the bullet on replacing those precats with aftermarket metal core units, you may want to browse your vehicle-specific forums to see whether or not it's a problem in the Infinity RWD platforms. I know that this issue was very prevalent on all FWD VQ35 (and QR25) engined platforms due to precat placement (far too close to the exhaust header). The proximity to the exhaust header is what allowed the disintegrated precat material to be sucked back into any cylinder that was experiencing a "back-pulse" due to intentional valve overlap using the VVT system. This was done to eliminate the need for a dedicated EGR valve on these engines. Your RWD Infinity may have the precats far enough away that they would just send crumbled material out of the exhaust and eventually throw a CEL to let you know when they don't function anymore (which of course poses no risk to your engine).


I've been under the car a few times, it definitely has the pre-cats on the headers.

Quote:
As Garak said, you can potentially get less burning, but not necessarily (depending on the mechanism of oil use, your vehicle, your driving, your environment, etc). You have nothing to loose in trying something different. If nothing changes, you would have at the very least accomplished an oil change that was necessary anyway!!! lol


Yeah, I figure it's worth a shot. I'm going to pick up some GC (BC?) 0w30 today and try it out.

 

[supra911]

on my 2003 G35, I felt that GC 0w30 worked the best.

Car burned about 0.75 quart every 5,000 miles with GC.

The worst burn rate was with Castrol Titanium? The gold bottle.
PP was pretty bad, also. Not sure, if PU was any better.

M1 5w-30 wasn't so hot, M1 0w-40 I can't remember, I didn't want to be TOO thick.. So GC 0w30 kept my consumption at bay.

 

[OCDriver]

Quote:
Car burned about 0.75 quart every 5,000 miles with GC.


That's about 1/3 of the rate I'm going through with M1 5w30. I'd be pretty happy to get it down to that!

 

[OCDriver]

Well, I put in the Castrol Edge 0w30 ("Belgium Castrol") in today.

Only thing I noticed on the first start is some possibly louder piston slap, but I'm not totally sure as I don't normally start the car with the hood open and I was probably listening more carefully than usual. I did prime the filter (Mobil1 M-108).

I'll do another cold start tomorrow.

 

[UltrafanUK]

Originally Posted By: artificialist
Originally Posted By: OCDriver
Quote:
I did however get rid of the ceramic pre-cats early on as those were known to disintegrate and get sucked back into the engine, thus destroying the rings

Alrighty then... getting rid of those ASAP!

Quote:
Keep an eye on the oil level. Running these engines on low oil will stress the timing chain.


Absolutely. I check it several times a week.




Very true, as NOX is nasty stuff!

Oddly enough tampering with emissions control gear is defined as a criminal rather than a civil offence in the EU and the annual MOT (Or biannual TUV in Germany) does check if the EGR, CAT or DPF have been deleted. Removing one of those items can also invalidate some insurance policies and if you get caught, they are not cheap parts to replace.

 

[OCDriver]

I'm in North America (Canada). The only time they ever check
emissions equipment here is done as part of the safety inspection when you transfer the registration of a vehicle to a new owner (ie/: buying or selling). After that, there's nothing. May vary by province/state, but I've never heard of any stringent periodic safety/emissions in North America as there are in Europe and Japan.

 

[RD400]

Originally Posted By: ukmastermind
Nissan VQ Engines

Here's the article. Just an FYI for all VQ fans


Thanks, very good info.

 

[OCDriver]

Quote:
I've been under the car a few times, it definitely has the pre-cats on the headers.


OK, I may have been wrong about this, with regard to my understanding of pre-cats actually are. But I can see that the cats are basically part of the downpipes in this exhaust design. Further research is required...

 

[NormanBuntz]

On my wife's 2007 M35, I was a steady user of Kendall synthetic blend 5w-30 for the first 67K miles. It had almost no oil consumption. I switched to QSUD and the engine used a quart in 2,000 miles. Being not happy with that, and since Kendall was getting harder to find, I started using my own blend of 2 quarts QSUD and 3 quarts of QSGB. Almost no oil consumption since 67K. Car has 92K now. Plus I enrolled in the QS engine protection plan, for what it's worth.

Many people have said these VQ engines prefer premium 5w-30 conventional. I opt for the blend.