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#2152457 - 01/27/11 10:28 AM Is it okay to use 5w40 instead of 5w30?
mrKiKaZ Offline


Registered: 05/25/10
Posts: 13
Loc: Rancho Cucamonga, CA.
Is it okay to use 5w40 in my car that the manufacturer calls for 5w30?
I'm so confused on the topic of switching to a higher weight oil. Ie. Tight Bearing clearance of today modern engines. The reason I want to try 5w40 is because I've noticed more oil consumption then normal but have no leaks or smoke from the exhaust. I was thinking the 5w40 would reduce oil consumption and provide better high temp protection.
So can someone clarify if its okay for me to switch from 5w30 to 5w40 oil? This is on a 2006 Scion TC 2azfe if it matters.

This is my final source to possibly find the correct answer. Thanks

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#2152464 - 01/27/11 10:35 AM Re: Is it okay to use 5w40 instead of 5w30? [Re: mrKiKaZ]
addyguy Offline


Registered: 09/08/05
Posts: 13448
Loc: Canada
There are lots of avenues you can go to try and reduce oil consumption.

Many on here would say to try and clean the engine to 'free up the rings' - try to run a quart of MMO in with 1-2 fills of oil to see if it helps.

As far as thicker oil, first try a High-Mileage oil before you do to a diesel 5W-40 - try Valvoline Maxlife 10W-30 and see if it helps.

5W-40 won't hurt, and if you really want to try it, go ahead. Rotella T6 5W-40 is a good, inexpensive option that is well-liked on here.
_________________________
2003 Mazda Tribute LX V-6, 175k miles.
Oil: QS Defy 5W-20; Fram Ultra XG2 filter.

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#2152498 - 01/27/11 11:06 AM Re: Is it okay to use 5w40 instead of 5w30? [Re: mrKiKaZ]
Loobed Offline


Registered: 07/20/07
Posts: 3742
Loc: Northern California, USA
Originally Posted By: mrKiKaZ
Is it okay to use 5w40 in my car that the manufacturer calls for 5w30?
I'm so confused on the topic of switching to a higher weight oil. Ie. Tight Bearing clearance of today modern engines. The reason I want to try 5w40 is because I've noticed more oil consumption then normal but have no leaks or smoke from the exhaust. I was thinking the 5w40 would reduce oil consumption and provide better high temp protection.
So can someone clarify if its okay for me to switch from 5w30 to 5w40 oil? This is on a 2006 Scion TC 2azfe if it matters.

This is my final source to possibly find the correct answer. Thanks



Some brands of oil get consumed faster than others even for the same weight. It seems odd, but that's what I noticed. Did you change oil brands?
_________________________
Engine: 2001 GM 5.3L LM7
Current Fill: Valvoline Synpower 5w-30 w/Pure-One PL25288 filter

I.M.N Oil Enthusiast

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#2152500 - 01/27/11 11:10 AM Re: Is it okay to use 5w40 instead of 5w30? [Re: mrKiKaZ]
Audi Junkie Offline


Registered: 11/03/02
Posts: 11247
Loc: PA
Try a 10w-30 if it's above 0f. Hi-Miles oils are great for this.

Just don't use plain Mobil 1 5w-30 if you want low consumption.
_________________________
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#2152516 - 01/27/11 11:28 AM Re: Is it okay to use 5w40 instead of 5w30? [Re: mrKiKaZ]
bepperb Online   confused


Registered: 01/10/08
Posts: 4815
Loc: Milwaukee, WI
I'd change your PCV valve first. 40 weight is pretty thick for the engine, but you're certainly not going to hurt anything by trying it (besides fuel economy, cold starting).
_________________________
2004 Highlander 2.4
2011 Toyota Sienna 3.5
Recently Gone:
2006 Accord 2.4l K24A8
1993 Kawi EX 500

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#2152528 - 01/27/11 11:44 AM Re: Is it okay to use 5w40 instead of 5w30? [Re: mrKiKaZ]
d00df00d Offline


Registered: 10/20/05
Posts: 9291
Loc: PA
Originally Posted By: mrKiKaZ
Is it okay to use 5w40 in my car that the manufacturer calls for 5w30?
I'm so confused on the topic of switching to a higher weight oil. Ie. Tight Bearing clearance of today modern engines. The reason I want to try 5w40 is because I've noticed more oil consumption then normal but have no leaks or smoke from the exhaust. I was thinking the 5w40 would reduce oil consumption and provide better high temp protection.
So can someone clarify if its okay for me to switch from 5w30 to 5w40 oil? This is on a 2006 Scion TC 2azfe if it matters.

This is my final source to possibly find the correct answer. Thanks

Thicker oil could decrease your oil consumption... or increase it. Depends on what's causing it.

How much oil consumption are you seeing?
_________________________
2011 Mazda RX-8 R3
Castrol GTX 5w-20

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#2152557 - 01/27/11 12:03 PM Re: Is it okay to use 5w40 instead of 5w30? [Re: mrKiKaZ]
A_Harman Offline


Registered: 10/01/10
Posts: 4374
Loc: Michigan
Since you are in southern Ca, I think you could switch to a 10w30, and not worry about cold start issues. Going to a 40-weight oil wouldn't hurt the engine, but it isn't necessarily going to decrease oil consumption. NOACK volatility numbers on oil spec sheets can give an indication if the oil is going to evaporate in the engine. (Lower numbers would be better.) Since your car is a 2006, it doesn't seem like it should be needing a high-mileage oil yet, but it couldn't hurt to try one. addyguy was suggesting Valvoline MaxLife 10w30. That may be a good one to try. But give it some time to work.

How much oil is your car using?
_________________________
1985 Z51 Corvette track car
2002 Camaro Z28 LS1/6-speed
2001 Dodge Ram 2500 diesel
1972 GMC 1500 shortbed project truck

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#2152568 - 01/27/11 12:09 PM Re: Is it okay to use 5w40 instead of 5w30? [Re: mrKiKaZ]
crazyoildude Offline


Registered: 07/23/08
Posts: 5593
Loc: new jersey
Try a high mileage 5w30 api sm oil of your choice


Edited by crazyoildude (01/27/11 12:12 PM)

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#2152569 - 01/27/11 12:09 PM Re: Is it okay to use 5w40 instead of 5w30? [Re: mrKiKaZ]
CATERHAM Online   content


Registered: 11/18/05
Posts: 9716
Loc: Burlington, Ontario, Canada
Originally Posted By: mrKiKaZ
Is it okay to use 5w40 in my car that the manufacturer calls for 5w30? I was thinking the 5w40 would reduce oil consumption and provide better high temp protection.
So can someone clarify if its okay for me to switch from 5w30 to 5w40 oil? This is on a 2006 Scion TC 2azfe if it matters.

First you haven't mentioned what your oil consumption is?
All engines consume some oil by design. Since there isn't any visible smoke, adding a quart or so between oil changes is no big deal.
Secondly, using a thicker oil than specified by the manufacturer will not provide "better" high temp protection. In fact it will detract from the efficient lubrication of your engine.
_________________________
74 Lotus Europa 5W-50
86 Porsche 928S TGMO 0W-20 25%/M1 0W-40
96 BMW 328i Idemitsu/TGMO 0W-20 70%/M1 0W-40
94 Caterham 7 Sustina 0W-20 80%/0W-50

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#2152632 - 01/27/11 01:20 PM Re: Is it okay to use 5w40 instead of 5w30? [Re: mrKiKaZ]
dtt004 Offline


Registered: 08/13/10
Posts: 314
Loc: Orange County, CA
Hi.

Caterham has some excellent points. All engines consume some amount of oil.

However, higher viscosisty oils do provide better high temperature protection. But it's not so simple. Think about it this way.

If the oil provides higher temperature protection, outside the normal operating temperature of your engine, then what good does it do for you? This is when Caterham's point about efficient lubrication comes into light. Choosing the correct viscosity is a play on efficiency. Everyone wants power, protection, and fuel economy. Well, those three are all at odds with each other.

The engine in your tC is wonderful for what it was built for. However, it simply isn't a race-inspired engine and the tC isn't a sports or sporty car. The lubrication requirements are different, and in your case, unless you do lots of extreme things with the car, an XW-40 won't hurt it in any way. It is ok. However, it's not required because XW-30 will do the trick just as well.

Hope this forum helps!
_________________________
Technical Design Engineer
--
1991 Toyota MR2 Turbo
1993 Mazda RX-7 Turbo
1996 Toyota Tacoma V6 4x4
2005 Acura NSX
2008 Lotus Elise
2004 Kawasaki Ninja ZX-10R

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#2152905 - 01/27/11 06:59 PM Re: Is it okay to use 5w40 instead of 5w30? [Re: dtt004]
CATERHAM Online   content


Registered: 11/18/05
Posts: 9716
Loc: Burlington, Ontario, Canada
Hi dtt004,

Except it is misleading to say "higher viscosity oils provide better high temperature protection". The implication is that if some viscosity thickness is good , more is better and will result in reduced engine wear. And that's where the misunderstanding comes in.
There is an optimum viscosity; lets say for the sake of argument it's 4cP using the HTHS viscosity methodology. In a hydrodynamic lubrication system that is the point just before metal to metal contact occurs under maximum load conditions.
When a manufacturer specifies an oil they have all ready factored in a safety margin to deal with every conceivable condition whereby viscosity loss can occur including maximum oil temp's, oil shear and fuel dilution.
Consiquently, using the oil grade that's specified makes it virtually impossible to approach the minimum optimum viscosity as hot as you think your engine oil is getting, there is always some reserve safety margin. Running an oil heavier than specified by the manufacturer on the assumption that you're providing additional protection, is basically blindly second guessing the engineers that designed your car; not a smart thing to do.
There are many negative consiquences of running a heavier oil that don't add protection such as reduced oil flow and more retained heat in the engine, specifically in the bearings.
Now some will say that you won't notice the reduction in power or the reduced fuel economy, and that maybe so, but why accept any negative attribute with no real upside gain?
_________________________
74 Lotus Europa 5W-50
86 Porsche 928S TGMO 0W-20 25%/M1 0W-40
96 BMW 328i Idemitsu/TGMO 0W-20 70%/M1 0W-40
94 Caterham 7 Sustina 0W-20 80%/0W-50

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#2152984 - 01/27/11 08:03 PM Re: Is it okay to use 5w40 instead of 5w30? [Re: mrKiKaZ]
ARB1977 Offline


Registered: 06/12/05
Posts: 4515
Loc: North Texas
Originally Posted By: mrKiKaZ
Is it okay to use 5w40 in my car that the manufacturer calls for 5w30?
I'm so confused on the topic of switching to a higher weight oil. Ie. Tight Bearing clearance of today modern engines. The reason I want to try 5w40 is because I've noticed more oil consumption then normal but have no leaks or smoke from the exhaust. I was thinking the 5w40 would reduce oil consumption and provide better high temp protection.
So can someone clarify if its okay for me to switch from 5w30 to 5w40 oil? This is on a 2006 Scion TC 2azfe if it matters.
I ran 15W50 in my Honda once...never burned before. I bought some Mobil One frolic my father in law. The car handled it but ran like poo. Instead of 5W40 I would try Mobil One 5W30 HM.

This is my final source to possibly find the correct answer. Thanks
_________________________
2002 Tacoma 3.4L 163K (as of 09-21-14)
M1 Super HM 5W30 & MoS2 / Fram Synthetic

2008 CRV 2.4L 105K (as of 03-22-14)
PP 0W20 & MoS2 / Honda A02

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#2153145 - 01/27/11 10:56 PM Re: Is it okay to use 5w40 instead of 5w30? [Re: mrKiKaZ]
mechtech2 Offline


Registered: 09/05/06
Posts: 19479
Loc: Chicago Area
You could also try 1/2 and 1/2, instead of all 5-40.
But the idea of using a HM oil in 5-30 is a better first step.

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#2153150 - 01/27/11 11:00 PM Re: Is it okay to use 5w40 instead of 5w30? [Re: mrKiKaZ]
Cristobal Offline


Registered: 01/02/11
Posts: 2029
Loc: Montebello, CA
I would see no harm in the heavy weight oil. The winter weight is OK for SoCal. You live in Cucamonga, do you mostly stay south of the Cajon Pass? Of course if you are on the 210 at high speed you might burn more oil I suppose.
_________________________
1996 Toyota Avalon - "The Beast"

The Poodle Empire will conquer the Galaxy. All Cats must die!

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#2153174 - 01/27/11 11:28 PM Re: Is it okay to use 5w40 instead of 5w30? [Re: addyguy]
jorton Offline


Registered: 07/04/03
Posts: 2773
Loc: San Antonio, TX
Originally Posted By: addyguy

5W-40 won't hurt, and if you really want to try it, go ahead. Rotella T6 5W-40 is a good, inexpensive option that is well-liked on here.


If a little fuel is getting in the oil, the Rotella will be perfect.

When the engine is cool, take off the oil fill cap and smell the fill hole for fuel. It should not smell like the gas tank.
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