Is it okay to use 5w40 instead of 5w30?

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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
 
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.
 
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?
 
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.
 
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).
 
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?
 
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?
 
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.
 
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!
 
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?
 
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
 
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.
 
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.
 
How much oil consumption are we talking here? About how many miles before you have to add a quart?

What are your driving habits with this vehicle? Lots of stop and go, mostly highway, or a mix?
 
I doubt a 5W-40 will hurt anything, but other than the possibility of a small drop in consumption, it won't help, unless you're running the engine much, much harder than normal, and seeing very high oil temps.
 
Probably the bearing clearances aren't much different than previous engines Japanese engines have always had tighter clearances . WHAT THE OIL CONSUMPTION? If you had a hundred of the same engines operated in the same way some would use oil and some wouldn't, the bell curve thing. I used to fleet repair work and had the pleasure of learning some precious tidbits as such!!!A 5w-40 could be a big jump in viscosity. You want oil thin enough so the oil doesn't cost you power yet thick enough to protect your engine.
 
Hey guys,

Thanks for all the informative information. Here's a little more info about my car.
It is supercharged and has 130k, mainly from lots of freeway driving daily with occasional spirited drives in the canyons and track days . I replaced the pcv valve like someone suggested yesterday, but the old one still seems good (never ever replaced).
Up to 115k miles my car would use no more then 1qt for 5000 mile oci.
Since 115k I've started to use just below 2qts for 5000 mile oci.

My owners manual says max oil consumption can be up to 1.1qt for every 600 miles. That seems really excessive! My cars never had to use near that much.

So far it sounds like 5w40 would be fine to run in my car but not the best choice. I suppose I should stay in the xW-30 oils, definitely going to try out high mileage.
While I'm not a fan of Mobil 1, they seem to be the only brand that offers a high mileage in full synthetic as I would like to stay with full synthetic oil even though I've read great things about valvoline maxlife. Seeing that I live in Socal, I'm probably going to try 10w30 high mileage.

Regarding use of rotella 5w40, I've emailed shell and was informed not to use it because my car still has catalytic converters in exhaust system.

I also had a UOA done fairly recently when I was using Castro edge, now I'm using Pennzoil ultra, still the same oil consumption with both BTW.

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1902754
 
Valvoline does make a Full Synthetic version of MaxLife. It is available in both 5w30 and 10w30 in jugs at some, but not all, of the WalMarts in my area. You might also want to consider that oil, if you can find it. Going with M1 HM in either 5w30 or 10w30 is also a good choice, if you can't find the Valvoline.
 
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