# 5W-30 or 10W-30



## nissanowner1 (Sep 11, 2005)

hi guys, could you tell me if i should put 5w or 10w into my 1997 nissan PF with 3.3L and V6. i went to murray's today and the guy that works there recommended to me to put 10W 30 since i have 155,000 miles in my SUV. but in the manual it is recommending 5W-30. could you guys give me some suggestions please. btw, i am using the mobil1 synthetic. thanks again guys.


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## asrautox (Jan 6, 2006)

either one is fine, and wont make much difference. If it's cold where you are now, the lower viscosity should make for better startups (ie 5w-30)..


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## 95'BlackP-Finder (Nov 24, 2005)

Hello, there...I have a 95' Pathy. A while back i asked myself the same question..All my 17 years of life, I have been surrounded by "Shade-Tree" mechanics whos theories are thicker oil in summer, thinner in winter..Thicker oil for valve ticks, worn lifters..etc..I'v heard them all, and im sure you have too...After only one short year of attending my local Area Technical Center in Automotive Technologies, being educated by a million times over ASE certified mechanic, I now know the accurate answer to that age old question... This one goes out to everybody: 

1.What your engine specifications call for..USE IT..!!! 5w-30, 10w-30, etc.

2.Some engines I know it doesn't matter, like my brothers 98' Frontier 4 cyl...It recommends either.

3.However, many don't..My Pathy...5w-30 only. I was using 10w-30..Quickly changed that as I lived and learned..

4. Reason being: The holes drilled in your engine block were drilled and temp tested for the weight of oil in your owners manual. Using a thicker oil, may not harm a vehicle for many many years, but a thicker oil than whats recommended CAN eventually cause an engine to pretty much wear itself out.. A thicker oil takes longer to heat, resulting in it taking longer to be pumped through the pin sized holes to lube valves, lifter, pretty much everything.

Hope that helped and clarified your situation. 

Also...I haven't quite figured out why he'd recommend a thicker oil for higher mileage..Thats more " Shade-Tree" work if you ask me, but hey..I"m just a kid in the process of being tought........."By A Professional" 

P.S...I'd like to add in my views of the best oils to use..

Pennzoil(of course) It's all I'll use.
Castrol makes a good oil.



Stay away from Quaker State. 
Valvoline I don't care much about...
Same for Halvoline.


P.S.S..Never mix brands of oil....mixing weights of the same brand is Okay, but never ever..ever mix brands...It will produce a foam that's A KILLER...I have witnessed this...


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## Pepco1 (Feb 3, 2006)

95'BlackP-Finder said:


> Hello, there...I have a 95' Pathy. A while back i asked myself the same question..All my 17 years of life, I have been surrounded by "Shade-Tree" mechanics whos theories are thicker oil in summer, thinner in winter..Thicker oil for valve ticks, worn lifters..etc..I'v heard them all, and im sure you have too...After only one short year of attending my local Area Technical Center in Automotive Technologies, being educated by a million times over ASE certified mechanic, I now know the accurate answer to that age old question... This one goes out to everybody:
> 
> 1.What your engine specifications call for..USE IT..!!! 5w-30, 10w-30, etc.
> 
> ...



My owners manual for 06 says to use 5w-30, but you can use 10w-30 if temperture is 0' or above. Where I live it never gets below 15' so which one should I use??? What is the difference in the two??? I have always used 10w-30 in my Toyota truck.


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## Bror Jace (Apr 26, 2003)

You had a really good post *95'BlackP-finder* and then you had to say the following:

_"Stay away from Quaker State."_

There are no bad oils these days. The horror stories associated with Pennsylvania oils such as Quaker State and Pennzoil are decades out of date.

_"Valvoline I don't care much about..."_

OK, here I agree ... but still it's not a bad oil, just an over-priced one with a bland-looking additive package 

_"Same for Havoline."_

Havoline (and Chevron Supreme) are two of the best conventional oils going. Lab tests (UOAs) show these oils to be practically identical to Pennzoil ... all use a Group II or II+ base oil and have healthy doses of boron & molybdenum anti-wear additives.

_"P.S.S..Never mix brands of oil....mixing weights of the same brand is Okay, but never ever..ever mix brands...It will produce a foam that's A KILLER...I have witnessed this..."_

While I feel that people mixing oil brands and weights are usually kidding themselves if they think they are producing a superlative brew, I have seen multiple UOAs showing no ill effects from mixing brands and weights of motor oil ... in fact some show incredibly low wear.

One thing to avoid is using gear oil in an engine ... even an old clunker. The additive chemistry in gear oils (especially older/cheaper stocks) tends to be slightly corrosive and bad for lead-type bearings and other soft metals.

One thing that (supposedly) causes foam in some engines is over-filling because the crankshaft turning in oil can whip it into a froth.


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## nissanowner1 (Sep 11, 2005)

hi guys, thanks for all the responses. i asked my son to change the oil already. unfortunately we already put the 10w-30. its not that cold anymore here in chicago. hopefully it wont hurt my SUV. i need this truck to and from work. do you guys suggest for me to go back to 5w-30 then? i put the mobil1 synthetic oil. is it ok for me to leave this type of oil for about 4 months? what do you guys think? thanks again in advance.


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## Bror Jace (Apr 26, 2003)

Mobil 1 in 10W-30 will pump OK well below zero fahrenheit.

It's March already and the coldest days are behind us. I say you're fine for the next 5,000 miles.


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## modvp (Dec 18, 2005)

I use Mobil 1 10W-30 synthetic in my 05 pathfinder.


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## sgott17 (Oct 18, 2005)

*oil*

heck if the new pathfinder says 5W30 why and the heck is Nissan putting in 10W30 for an oil change? Does this really matter? I can see if they are putting in gear oil in place of motor oil! I used 10W30 Penzoil in my honda and Mazda car and the honda has 102K and the mazda i got rid of with 150K and neither uses or leaks oil! Penzoil is my favorite and I am sticking with it! Nissan did my last oil change since it was time and it was there to get the recalls done! Otherwise, I do it myself. They charge $30 for oil change it costs me about 12!


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## FoolmeNot (8 mo ago)

The reason experienced mechanics say run a slightly thicker oil in higher mileage engines is due to tolerance changes in an engines rings/valves/bearings/seals. A thicker oil fills in these gaps so an engine burns less oil, the oil pressure remains high to lube better slowing future engine wear. Generally its raised from 10w30 to 10w40 on older engines.
Old high performance muscle cars with high compression engines always do better with straight 50wt all yr round. It slowed wear during extremely hard driving conditions as most of us drove those cars to work weekly & on the track every weekend. I ran straight 50 in my old 69 Dodge Super Bee (Hemi) and after 230k of very hard miles it never burned oil between changes. While most other people ran what manuals said to run (10w30) had issues at 100k or less on the Hemi. Most never saw a track even and still had valve wear with rebuilds on top end or full engine rebuild/replacements.
I was just told by a nationally known drag racer & mopar dealership owner (Dave Duell) to always run straight 50wt in mine cause I raced it. He explained on hot days at high rpm thinner oils get slung right off moving parts creating more metal wear. That made since for sure. The fact thicker oil slows wear was proven by racers decades ago btw. 
Today however, 10w40 is the thickest most people should run as engine tolerances are much tighter than those older engines. Chains/belts now have hydraulic tensioners we didn't have back then. A 50wt is too thick to flow quickly enough in cold temps quite possibly causing timing chain/belt failure on start up now days. The facts are still the same as wear goes but engines have changed. But why 20wt, its like water when heated??
Well its not because its better, no its worse as far as wear. But' Gov EPA mandates will actually fine auto makers if a certain % of their vehicles fail to reach a set amount of mpg ratings. This mandates been around yrs & just keeps on raising every time car corps turn around. Now its forcing all electric soon!! Trust me its always raised regardless if a left/right is in office. Not one pres has tried to get rid of it since it all began decades ago, many used it for political gain yes but never tried ending it once in office so its not our left/right it is in fact both sides or above both??
Anyway this is why most all new cars have mpg rated tires (little to no tread to shave roll resistance), super light 5 or 0-20 grade oil that protects an engine far less than other grade oils and plastic wherever they can possibly put it even in/on the engine where designers really prefer metal for durability. The thinner the oil is the more it cuts down on resistance when the crank runs through the oil inside the oil pan. Better MPGs!! Most engines today also use an old school racers trick where we'd grind the edge of each counter weight on the crank so it slices through the oil like a knife for less resistance, this keeps RPMs up. 
Its to keep mpg up now days but that trick was all about hp gains in the beginning. They also use a Mopar OEM trick of installing a windage tray to catch part of the oil so theres less oil in the oil pan that slows the cranks counterweights passing through it. Mopar first used them in their 60's muscle cars. Cadillac tried to copy this Mopar performance trick on the NorthStar engine but failed miserably doing so and their NorthStars leaked oil like a seive. My nephew had one and Cadillac told him $1800 to repair its leak but can't guarantee it wont still be leaking when he picks it up..lol True! Typical GM cut corners in manufacturing and then buys awards to make up the sales loss. (See link)
Mopars never leaked a drop from their WT. 
One other thing, oil corps advertise "high mile Motor oils" aimed at 75k mile engines. Do not use "High mile engine oil" unless your engine is already having issues with oil burning, valve noise, smoke etc..
High mile oil swells rubber seals, valve seats etc to slow leaks & oil use but once its used it must always be used because the rubber stays out of spec.
Splitting in rubber parts have been associated with some high mileage oils swelling too much. 
sorry long post..
https://www.google.com/amp/s/gmauth...-buying-awards-for-itself-and-mary-barra/amp/


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## VStar650CL (Nov 12, 2020)

FoolmeNot said:


> Anyway this is why most all new cars have mpg rated tires (little to no tread to shave roll resistance), super light 5 or 0-20 grade oil that protects an engine far less than other grade oils and plastic wherever they can possibly put it even in/on the engine where designers really prefer metal for durability.


There are also VVT systems to worry about on practically all modern engines, and the hydraulic types don't work well with heavy viscosities. The trade for that is no longer being saddled with unreliable and horsepower-robbing EGR Valves on most engines, so I'd call that a good tradeoff. The wear protection with thinner weights also isn't the factor it used to be in the muscle car era. Better refining techniques mean the film strength of even cheap oil nowadays is far better than the bad old days. Molecular uniformity and film strength are the ultimate determiner of when metal meets metal, not viscosity, and splash- and squirt-lubricated parts like piston crowns and wrist pins actually benefit from lower weights. Those are factors modern engine designers use to good effect. You won't see anything from the muscle period running 300K miles and more like, say, an R51 Pathfinder VQ, and there are many R51's out there with that kind of mileage still running 5W and 10W oil.


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## FoolmeNot (8 mo ago)

Oh I saw many old 60's cars hit 300 to 400k without rebuilds. The old 327 engines hit 300 with ease.
My friend had a 69 Goat with 400k on it.
It wasnt until unleaded gas hit cars struggled to hit 100. There were still many I personally owned/saw with 300k. I had a 1963 Dodge 3/4 ton truck in 80's with slant 6 with over 400k. I put 300k in it and it was running fine when I sold it.
Unleaded gas sure sucked the life out of the old engines. Hey were alive to see it though cause the lead was killing us.


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## VStar650CL (Nov 12, 2020)

FoolmeNot said:


> Oh I saw many old 60's cars hit 300 to 400k without rebuilds. The old 327 engines hit 300 with ease.
> My friend had a 69 Goat with 400k on it.


Show me. I owned both a 327 Impala and a '67 Goat, and with 60's production tolerances and 60's lubricants, you were doing _very_ well to hit 150K without a rebuild. Sounds to me like you have a case of terminal nostalgia.


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## FoolmeNot (8 mo ago)

No I bought/sold antique and muscle cars for 27 yrs. I owned over 200 in my past until health issues sidelined me. Not owned just one or two cars like you then thinks he knows it all?
Fact is you simply dont know how to care for your engines correctly to get high miles out of them honestly speaking cause Ive seen/owned many "many" old cars with twice your mileage.
That 64 Dodge truck seat was just wire springs as its horse hair was all the way gone on drivers side. It had so many miles, its door latch wore down so far only a bungy held its door closed. I still used it for a hauler and so did the guy I sold it too. It never had an overhaul in its 300k+ miles I drove it is a fact.
First engine I saw hit 300k was a friends/moms 1970 LTD 4dr with the 302. Our old party mobile, his mom bought it new and each of her 3 sons drove it through school after her as a hand me down.
Idk what or where it ended up, I got married (grew up) & he joined the Army after college so his dad sold "Long [email protected]".
It had a short #2 pencil in the rear tire as a plug for 2yrs I remember, idk if he ever fixed it right? His maintenance was top notch..lol
2yrs ago I sold my 65 GS Riviera I used as my daily since 1970. I fully restored the car with 230k miles back in 1998. It has the Dual Quad 465 (425 c.i.) Wildcat engine aka: NailHead in it. 
Prior to restoring I never had the heads off so it never even got hardened seats for unleaded fuel installed. Always ran perfect so why bother, my old boss still drives my old GS today.
Many of the old engines are full of nickle so metal wear was min for many miles. GM made several but I guess you dont own any nickle blocks only their lower end blocks if
150k is the best you can get? 
Like most people love to do you likely run the biggest Holley you can run on a car so you go too rich and/or you fail to change their plugs soon enough so the excess fuel is destroying your bearing/cylinders way early.
Ive seen it a thousand times so your not alone dont feel bad.
My friends old GTO exhaust was always grey/white after our road trips, he ran it so lean it worried me. That ol' Goat ran lean forever though, but of course it was fugly green too so maybe that was why it lasted so long? I mean hey we all know ugly cars just last forever. Especially baby chit yellow ones..aka Butter Scotch..omg.
I couldnt even begin to count all the Grand Prix 400's I seen with over 200k miles, trust me your doing something seriously wrong if 150k is the best you can do on a Pontiac engine. By far one of the better engines. The last 400 I owned was a 79 Macho T/A (400 5spd). I finally sold it back in early 90's with 73k mi because its value was never going to take off like it should have. It was the last of the big block cars but nobody ever cared. Only car I lost money on btw.
If you only learn how to maintain a car right you'd get more miles like others get from those engines.


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## VStar650CL (Nov 12, 2020)

I love know-it-alls and I love stories. I had a "friend" too in college, who used to point at the giant miles on his VW Microbus. Never told anybody it went through 2 engines and six overhauls to get there. I know lots of people who claim giant miles on lots of old cars, and I know lots of people who lie about it. Most of them are the same people. When you dig, you find out they've all been re-done with modern materials. That matters, because CAD/CAM revolutionized the tolerances of replacement parts in the '80's. When you rework a "classic" today, you aren't reworking it with 1960's parts.

FYI, the Goat was converted to Tri-Power because I bought it with a blown engine. That proved (as usual) to be impossible to tune, so it got a _properly_ tuned vacuum Rochie. Holleys are junk.

I repeat, _show me_.


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## FoolmeNot (8 mo ago)

VStar650CL said:


> Show me. I owned both a 327 Impala and a '67 Goat, and with 60's production tolerances and 60's lubricants, you were doing _very_ well to hit 150K without a rebuild. Sounds to me like you have a case of terminal nostalgia.


 Was not uncommon to see several hundred k on old cars. Especially on Mopars slant 6 engines. Why they were also used in military applications like generators and pumps. State/county tree crews used them in tree chippers too. Used to see them everywhere.
Who has the Highest Mileage Slant-6??


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## FoolmeNot (8 mo ago)

So you bought a ragged out goat needing an engine when you cant even tune a few 2bbls?..Wow!
Never mind..
You really are a smart guy.


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## VStar650CL (Nov 12, 2020)

Nobody could keep 3-2's idling without a weekly visit to carb sticks. Total PITA, everyone hated it. I expect you'd be smart enough to know that, smart guy.


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