rancor

Yes pressure would be lower on a 30 weight. You will need to test with a 30 weight and at the proper temperature (80 °C /176 °F). The HR has an oil temp sensor that can be read out using Nissan data scan III(Android app) the revup might also have one. Fully warmed up oil temp at least for me is 190-210F so the pressure will read lower.

As a side note why would you run a 50 weight? Do you live in the middle east or desert of australia?

Bilazaurus

Can't connect NDSIII, only Torque. I use 5w50 because it's preferred by mechanics here for better engine protection.
I've noticed as I pushed to 6000rpm on 1st gear that I've got only about 100psi. My water temp is 99celsius after 3 minutes from stopping the engine. BTW Should engine, oil and battery lamp lights on when key is in on (position after acc and before starter)? Also, when engine is hot I hear hissing on the passenger side of the engine like an air leak. Could a leak in pcv cause this?

Edit: I've just noticed. In the manual it states UNDER NO-LOAD. I've checked my pressure @ 2000RPM during driving, not standing. Should the oil pressure
at any RPM be higher under load than under no load?

rancor

Oil pressure at 6K rpm - That's normal but a little low. If you are using the stock gauge they are are not all that accurate. The oil pump will start to bypass once pressure gets over ~90 psi so the oil pressure shouldn't get much above that.

Dash lights - Totally normal when the engin is off. I think the engin light should go out after a little while but I am not sure sure. Oil light is on because you don't have oil pressure and battery is on because the alternator is not running.

Hissing sound - PCV leak could make a hissing sound but and could cause idle issues as you would have a vacume leak.

Oil pressure under no load - There won't be a huge difference maybe slightly higher under load but like I said before the stock gauge isn't all that accurate.

Checking the oil pressure against the FSM numbers from Nissan needs to be done with an external gauge while running 5W-30.

Bilazaurus

No peace of mind for me then. What is the optimal pressure for 5w50? Any one knows?

zakmartin

You live in a temperate climate. Why not just stick with the Nissan recommended 5w30? Just because some mechanics in your area prefer a different weight doesn't mean they're right for your application.

Bilazaurus

He worked on engines driven with 5w30 and says it's much to thin for a car like that. Seems possible as my 2 liter BMW E39 also uses 5w30 but is more than twice less powerful

travlee

iTrader: (8)

i would think nissan engineers would know what works best in the motor

Bilazaurus

Yes, I would think so too but I've heard that they stated 5w30 in manual because of economy or ecology concerns.

rancor

The engineers need to balance a lot of things including engin life and 5W-30 was deemed fine. If I am remembering correctly nissan said the HR should last 200,000+ miles. If you are running the engin outside of normal condition and heating the oil above normal driving than thicker oil might be needed. Think unrestricted autoban or sustained 3500/4000+ RPM. In general outside of racing you are unlikely to need anything over a 40 weight and even then may just need to run an oil cooler to keep temps in line and viscosity high enough.

If the gallery gaskets have failed, running 5W50 may have been part of the cause. With the thicker oil you are running higher oil pressures, especially when cold, and putting greater stress on the gaskets.

NR350z

Have to agree, if they are going its probably due to the higher oil pressure blowing them out, which how I think mine went after switching to 10w-30, going with suggested oil from now on, eventho 10w-30 is deemed "fine" by some

MicVelo

Rancor's last statement and zakmartin's before that ^^^ are as true as it comes.

Oil viscosity at any given moment is a function of TEMPERATURE. Thin 5 weight - hence "5w" for Winter (cold) - and 30 for max thickness when HOT (normal environmental op temp).

Unless you live in areas of extreme heat (as someone mentioned, the middle East or the Australian outback or [ pick your hot spot ], there is no reason to deviate from factory spec.

I also don't understand the comment about "economy or ecology concerns". What effect does using or specifying the standard 5w30 versus a wide range high viscosity, e.g., "5w-50", have on either of those?

Nissan engineers designed/specifies 5w30 for a reason and that is that it has been tested in the VQ in the widest ranging variety of operating environments from cold to hot. (But maybe not arctic cold or deep desert hot so yes, that does leave open the possibility that in cars spec'd for the aforementioned "hot environments", perhaps something different like a 0w40 or 5w50 or.... gear lube should be run. I kid on that last one of course.)

In any case, if you are running 5w50 in a modest, temperate environment, you're not going to hurt anything due to what I said in my second paragraph. That is, "oil is, for all intents, whatever it wants to be at that moment in time corresponded with the operating and ambient temperatures". I don't know Poland but from what I do understand, your oil should never thicken to anywhere near 50 weight unless subjected to extreme use, e.g., racing.

I understand you are concerned - and that's your prerogative - but IMO, unnecessary worry.

RobPhoboS

Out of curiosity, why did someone suggest using copper spray?

Xrabbix

Alot of people use it on gaskets, for these I don't think I'd recommend using it though

Atjstballin

how many miles was yours like that for? I'm experiencing this now