Oil and engine noise - My kitchen table test

[427Z06]

quote:

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Originally posted by 1sttruck:
Motorcraft recommends 5W50 in the 5.4L SC engine in the GT, Mobil has advertised that Mobil 1 15W50 was factory fill in some of the Ford high output modulars

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This statement is somewhat misleading. Ford recommends 5w50 in a couple of low production (thousands compared to millions) specialty engines made with aftermarket parts, and a vast majority have an aftermarket supercharger.

 

[427Z06]

quote:

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Originally posted by 1sttruck:
A Nascar race seems to often be 500 miles, while fast cars at Le Mans are doing over 3000 (?) miles.

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So give us all the specs on these Le Mans cars. What engines, bearing and piston clearances, piston type, valve train design, oil temperatures, fuel type, etc, etc.

Since inferencing seems to be the preferred sport for some, does that 3000 to 500 mile ratio infer that daily driven street engine are going to last 6 times longer using thicker oil than the manufacturer's recommendation?

 

[ekpolk]

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Originally posted by Dave H:
*snip}
Numerous posts here and on Maxima.org mention that Nissan VQ's like thicker 30 weights. The manual specs 5w30 as preferred, and 10w30 suitable. The European manual for the same car specs everything from a 5w20 (but stipulating not recommended for sustained high speed driving), up to a 20w50 for hot areas. Interestingly, it also states 5w30 will positively improve fuel economy, but 10w30 is preferable for ambient temps above -20*C. In fact, the 5w30 is only recommended up to a temp of +15*C (+59*F). These differences in recommended oils lead me to believe that thicker oils work better in VQ's. This is verified by many other VQ owners, and by my own observations. And Mobil 1 (a thin 30 wt) returned two sub-par UOA's in my car and made the car much louder, even to the "untrained" ear of my wife.
*snip}

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Dave:

Nice to hear from you. Don't forget, Nissan has gone a step further. In the current production VQ35, at least for US ones, they've added 10w-40 as one of the three recommended oils. 5w and 1w-30 are the others, of course, and in my G35 manual, 5w30 is still designated "preferred", and is the only one spec for all temps (10w-30 and 40 are for temps above 0 deg F). I find this engine to be a very interesting anomaly, at least when compared to the rest of the mainstream market which is, of course, shifting toward ever lighter oils. I'd really like to know what's different about the VQ compared to competitors that seem to like thinner oil. Mine too is noticeably harsher sounding when fed a ~10 cSt oil vs the 12+ cSt GC that I normally use.

 

[427Z06]

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Originally posted by Dave H:
427Z06,

I ran two back-to-back OCI's for roughly 4500-5000 miles each with Mobil 1 5w30 in my '97 Maxima. Both runs, the VQ30 engine was loud and vibrated enough to feel in the steering wheel while in Drive. Both UOA's of the Mobil 1 showed elevated lead and iron. I returned to Castrol GTX 5w30, and the engine noise and smoothness returned to "normal". I have since run GC, and the engine was even quieter and smoother than on the GTX. There also was no measurable loss of mileage, which I calculate in a spreadsheet to the nearest hundredth, and have for years. This was not only my subjective observation, but also my wife's, and without prodding from me (she asked me if it seemed quieter when she didn't know I had changed the oil).
Numerous posts here and on Maxima.org mention that Nissan VQ's like thicker 30 weights. The manual specs 5w30 as preferred, and 10w30 suitable. The European manual for the same car specs everything from a 5w20 (but stipulating not recommended for sustained high speed driving), up to a 20w50 for hot areas. Interestingly, it also states 5w30 will positively improve fuel economy, but 10w30 is preferable for ambient temps above -20*C. In fact, the 5w30 is only recommended up to a temp of +15*C (+59*F). These differences in recommended oils lead me to believe that thicker oils work better in VQ's. This is verified by many other VQ owners, and by my own observations. And Mobil 1 (a thin 30 wt) returned two sub-par UOA's in my car and made the car much louder, even to the "untrained" ear of my wife.
On another note about Mobil 1, is my Mother-In-Law's '99 GMC 1/2 ton has literally had a diet of only Mobil 1 from "birth", changed every 3000 miles (probably a waste of oil as it could go longer, but it's her truck). She now has 60,000+ miles, and her dipstick is "permanently" varnished. It will not wipe off, and is concentrated on the end that constantly sits in the oil. I don't know what to think of that, but thought I'd mention it.
Due to my 2 bad UOA's on Mobil 1, and varnish on my MIL's dipstick, I personally will not use Mobil 1 in my 2 Nissans. Others may get good results from it, but I personally have better results with Castrol GTX and GC.

For the 5w20 "thin is in" crowd, why would Nissan state 5w20 is not recommended for sustained high speed driving? And keep in mind this is for a Nissan VQ30, which has been on Ward's top 10 engine list since the list's inception. It's not likely that Ford has much tighter tolerances. I personally opine that it is CAFE driven, and especially when "non-CAFE" regions recommend higher viscosities. Just some food for thought/discussion.

Dave

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Dave, your engine didn't like Mobil 1, fine. It like GC the best, fine. Was it the viscosity or the formula that your engine prefered?

Since Nissan doesn't recommend 5w20 for sustained high speed driving, I wouldn't use it under such circumstances. (As a side note, that's what most owner's manuals that listed 5w20 said 30-40 years ago.)

As far as Mobil 1 severly varnishing your engine, I'd have to say it's surprising to me. I've run a half a dozen cars on Mobil 1 since their first oil change and never experienced anything but cleanliness. I've had the valve covers off most of them too and the oil pan off two of them. Sparkling clean inside all.

[ April 02, 2006, 11:34 AM: Message edited by: 427Z06 ]

 

[427Z06]

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Originally posted by Rodbuckler:

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Originally posted by 427Z06:
Further, an engine with that severe of piston slap is not going to be saved by going up a grade or two of oil. You're in LaLa Land now, Enjoy.

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I got just back from LaLa land. While I was there I added 3/4qt of Delo 400 15w40 to the 5 1/2 qts SL rated M1 10w30 SS in the crankcase of my 351W. Conclusions:
- Piston slap on cold start gone
- Engine a little smoother than before during hot operation

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Well good for you, Rodbuckler. You should call GM and tell them they can resolve all the complaints they receive about piston slap in their engines by adding 3/4 qt of Delo 400 15w40 to them.

 

[Ken E.]

My dad had the solution for annoying engine noises: turn up the radio.

 

[Rodbuckler]

quote:

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Originally posted by 427Z06:
You should call GM and tell them they can resolve all the complaints they receive about piston slap in their engines

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After they read this thread, GM will no doubt include my cup test in their next oil specification. It would have saved them millions.

 

[i]

Interesting about the varnish. I forgot that. M1 started to varnish up my engines too, right about the same time that it started turning black after only 150 miles on fresh oil.

 

[Rodbuckler]

quote:

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Originally posted by 427Z06:
Further, an engine with that severe of piston slap is not going to be saved by going up a grade or two of oil. You're in LaLa Land now, Enjoy.

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I got just back from LaLa land. While I was there I added 3/4qt of Delo 400 15w40 to the 5 1/2 qts SL rated M1 10w30 SS in the crankcase of my 351W. Conclusions:
- Piston slap on cold start gone
- Engine a little smoother than before during hot operation