Running a thicker oil than spec harmful?

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Originally Posted By: freedhardwoods
I run Rotella 15w40 with 20%-30% Lucas oil stabilizer year round in everything from lawn mower to semi. Most of my vehicles are high milage. Two with over 250,000 miles. My semi has 1,400,000 miles (400,000 on major overhaul).
Leave that Lucas stuff on the shelf, leave your money in your pocket, and you'll probably get even better results.
 
You will void a warranty if you run anything thicker than a 30 weight in VVT engines, especially the GM 5.3L engines.
 
Originally Posted By: MolaKule
You will void a warranty if you run anything thicker than a 30 weight in VVT engines, especially the GM 5.3L engines.


Wrong. My Nissan Maxima owner's manual specifically states 10W-40 is acceptable in temps above 0F. Maxima's have had VVt since 1992. They used this same basic engine design all the way back to the 1987 300ZX. After that many years in production, I'd say Nissan must be comfortable recommending 10W-40 in their VVT equipped engines.

As a matter of fact I'm going to switch over to that weight at the next oil change as my engine burns a quart of 5w30 every 1k miles. I'm hoping I can get away with running a 10W-40 synthetic and not experience the oil loss. This could be a whole new thread. What's better? 5w30 conventional or synthetic 10W-40?
 
Originally Posted By: kbohip72
Originally Posted By: MolaKule
You will void a warranty if you run anything thicker than a 30 weight in VVT engines, especially the GM 5.3L engines.


Wrong. My Nissan Maxima owner's manual specifically states 10W-40 is acceptable in temps above 0F. Maxima's have had VVt since 1992. They used this same basic engine design all the way back to the 1987 300ZX. After that many years in production, I'd say Nissan must be comfortable recommending 10W-40 in their VVT equipped engines.

As a matter of fact I'm going to switch over to that weight at the next oil change as my engine burns a quart of 5w30 every 1k miles. I'm hoping I can get away with running a 10W-40 synthetic and not experience the oil loss. This could be a whole new thread. What's better? 5w30 conventional or synthetic 10W-40?


Last time I checked, a Nissan Maxima did not have a GM engine. Further, I was unaware of Nissan having VVT in any engine until sometime past 2000. I certainly was not aware that my 99 model Maxima had VVT. That was not because I failed to rev it high enough for the VVT to activate, either. It saw 6400 many times as I had to enter a busy street going uphill as I was leaving my subdivision. Saying this, I stand to be corrected by someone in the know. Can some one tell us when VVT began to be used in Nissan V-6's.
 
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Originally Posted By: 1999nick
Originally Posted By: kbohip72
Originally Posted By: MolaKule
You will void a warranty if you run anything thicker than a 30 weight in VVT engines, especially the GM 5.3L engines.


Wrong. My Nissan Maxima owner's manual specifically states 10W-40 is acceptable in temps above 0F. Maxima's have had VVt since 1992. They used this same basic engine design all the way back to the 1987 300ZX. After that many years in production, I'd say Nissan must be comfortable recommending 10W-40 in their VVT equipped engines.

As a matter of fact I'm going to switch over to that weight at the next oil change as my engine burns a quart of 5w30 every 1k miles. I'm hoping I can get away with running a 10W-40 synthetic and not experience the oil loss. This could be a whole new thread. What's better? 5w30 conventional or synthetic 10W-40?


Last time I checked, a Nissan Maxima did not have a GM engine. Further, I was unaware of Nissan having VVT in any engine until sometime past 2000. I certainly was not aware that my 99 model Maxima had VVT. That was not because I failed to rev it high enough for the VVT to activate, either. It saw 6400 many times as I had to enter a busy street going uphill as I was leaving my subdivision. Saying this, I stand to be corrected by someone in the know. Can some one tell us when VVT began to be used in Nissan V-6's.


You said "You will void a warranty if you run anything thicker than a 30 weight in VVT engines." I simply responded that you are wrong on this, which you are. You never specified GM VVT engine, you just said "especially the GM 5.3l engines."

As for Nissan V6's having VVT? The VE30DE engine was the first engine to have VVT in the Maxima SE model in 1992. In that car there was a noticeable change in power at 3,500 rpm when the VVT started working it's magic. On 95 and up Maximas all models had the same 190hp VVT equipped engine but there was no sudden feel of power at 3,500rpm that my '92 had. The VVT design gave the Nissan V6 in the Maxima SE a 30hp increase over the standard 160hp VG30 V6 that was in all 89-91 Maxima's as well as the 92-94 GXE model Maximas.

This info was in every major car magazine in the early nineties as I used to read them all back then. I've also owned 4 Maximas over the last 15 years so I know a bit about them and their configurations. As for proof, these cars have gotten so old there's not much info on them anymore, but I did find this in Wiki:

The VE30DE engine, which was purpose-built for, and exclusively offered on the 1992-1994 Maxima SE, featured variable intake manifold (5-speed model only) and with variable timing cams, plus a limited-slip differential, became standard on the SE models in 1992.

The variable timing cams as they were called by Nissan back then were prone to failure. I bought a used '92 Maxima back in '95 that VTC's were already out on with only 30k miles. Got them repaired under warranty and got another 110k trouble free miles out of that car.
 
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Originally Posted By: MolaKule
You will void a warranty if you run anything thicker than a 30 weight in VVT engines, especially the GM 5.3L engines.


respectfully, why?

my 2AZ-FE owners manual allows 20w-50 above -7 deg C.
 
What is recommeded in Australia, Crinkles?
I always get a laugh out of the thin-only crowd, when much thicker oils are recommended for markets outside the US.
I doubt that any oil will hurt any engine, as long as ambient temperatures are suitable for the viscosity range used.
OTOH, MolaKule has forgotten more about oil than I will ever know.
 
Originally Posted By: MolaKule
You will void a warranty if you run anything thicker than a 30 weight in VVT engines, especially the GM 5.3L engines.

Does the system somehow sense the higher viscosity as a non-warm engine and fail to put the system into operation? - thus you have non-optimised valve timing at typ operating rpm and higher that can cause emissions and mixture problems? You would think they would have addded this exact scenario to the ECU programme as a fail safe. Please expand.
 
No, Toyota incorporates a coriolis detector. If crinkles could fool his toilet into flushing counter clockwise, his Toyota would automagically re-adjust the clearances so that the engine would only function properly with 5w30.

Ed
 
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respectfully, why?


I was referring to VVT's in general and the GM 5.3L VVT's specifically.

The reason is the cam-phased, variable valve-timing, cylinder deactivation-controlled engine has its own hydraulic system to activate and deactivate cylinders which determines whether the engine will be a 4, 6, or eight cylinder engine in order to improve MPG and power response.

The cylinder activation/deactivation is seamless and it not felt by the driver.

IF a high viscosity oil is used, extreme pressure surges can cause out-of-phase timing, lower MPG, and high levels of air entrainment which causes foaming and increased wear. As we all know, air is not a lubricant for automotive applications.

Pressure monitoring in this specialized internal hydraulic system is based upon a 30 weight engine oil's characteristic, to which the VVT system was designed.

Now, you CAN use anything from a 0W30 to a 10W30. I prefer a 0W30 for Winter and a 5W30 for summer for my 5.3L engine.
 
Originally Posted By: fdcg27
What is recommeded in Australia, Crinkles?
I always get a laugh out of the thin-only crowd, when much thicker oils are recommended for markets outside the US.
I doubt that any oil will hurt any engine, as long as ambient temperatures are suitable for the viscosity range used.
OTOH, MolaKule has forgotten more about oil than I will ever know.


Oil.jpg
 
Originally Posted By: MolaKule
Quote:
respectfully, why?


I was referring to VVT's in general and the GM 5.3L VVT's specifically.

The reason is the cam-phased, variable valve-timing, cylinder deactivation-controlled engine has its own hydraulic system to activate and deactivate cylinders which determines whether the engine will be a 4, 6, or eight cylinder engine in order to improve MPG and power response.

The cylinder activation/deactivation is seamless and it not felt by the driver.

IF a high viscosity oil is used, extreme pressure surges can cause out-of-phase timing, lower MPG, and high levels of air entrainment which causes foaming and increased wear. As we all know, air is not a lubricant for automotive applications.

Pressure monitoring in this specialized internal hydraulic system is based upon a 30 weight engine oil's characteristic, to which the VVT system was designed.

Now, you CAN use anything from a 0W30 to a 10W30. I prefer a 0W30 for Winter and a 5W30 for summer for my 5.3L engine.


OK great, so it is really the combination of the cylinder management and VVT that makes this "thin" oil required?
 
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OK great, so it is really the combination of the cylinder management and VVT that makes this "thin" oil required?


Yes, that is my understanding. As I stated, the internal hydraulic system design within the engine is sensitive to the viscosity of the oil used.

Now Toyota may have such a different overall architecture or engine design that it is not so sensitive to high viscosity oils.
 
Originally Posted By: Bill in Utah
You know the bottom line is in your engine the way you operate it where you live we don't know.
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And until you take a few down the long road and run the exactly the same with different oils the answer will not be known for sure.

With that said, I'd run what they recommended because we know that they DID test the engines up and down the road and had acceptable results. I'm sure that they also tried other oils and found something to be less so they went with worked.

The reasons for NOT using a thicker oil could be MPG, engine life, noise on start-up, lack of oil on cold start ups or many other things.

The reasons for not using a thinner oil could be engine life/wear, noise on start-up, lack of oil when warm or many other things.


Clear as mud....
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Where I live I see quite a few test fleets going down the interstate wrapped so you don't know what they are. They stop and get gas and I sometimes talk to them. They drive a TON of miles and then look at the results. I'd bet a few of the vehicles has some oil and the others have other oil. Some run this part and the other runs another. Nissan seems to really TEST the [censored] out here because I see them the most.

Take care, Bill
Yep.
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Originally Posted By: MolaKule
Yes, that is my understanding.
And thanks for sharing, I thought that was interesting.
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Huh!
I guess that oil behaves differently in the Southern Hemisphere?
Or maybe engines do?
Seriously, I don't think anyone need worry too much about using a thicker oil than is sepcified for the US, except for that pesky warranty thing.
Used Mobil 1 15W-50 in my '99 Accord this summer, and I really couldn't tell the difference, and I don't think the VTEC could either.
 
Originally Posted By: fdcg27
Huh!
I guess that oil behaves differently in the Southern Hemisphere?
Or maybe engines do?
Seriously, I don't think anyone need worry too much about using a thicker oil than is sepcified for the US, except for that pesky warranty thing.
Used Mobil 1 15W-50 in my '99 Accord this summer, and I really couldn't tell the difference, and I don't think the VTEC could either.


Some people in the U.S think their cars are the only ones that can last long. Also everyone else has gotten it wrong. I am now reading on here that thinner oils reduce oil burn (against oil manufacturer logic) next thing is i will read it stops leaks as well better than thicker oil. This should not be a general statement and yes some newer cars will have these properties. The thin oil thing stops dead in its tracks when you see what oil people in Europe use, with the same extremities of weather. Some people think 40w oils are the Devils number.

However there is an excellent trend being set on here now where people are advising use whatever suits your climate and within manufacturers guidelines. Each car is different, the owner will eventually know what runs best in their car.
 
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