Is Using 20W-50 Oil Good For Your Motor?

[GotToyota?]

Hey Jdub, sorry to bug you about this but...

The new car I'm getting on Saturday is confusing me, oil wise. The owner tells me he was running Mobil 1 20W-50, and after questioning the local Supra shop guy, he says a #W-50 is recommended in the owners manual. I was doubting this, but I don't have a owners manual right now to confirm. He was saying that because of the fact that many people don't run this oil, could be the very reason why so many people get rod knock. I'm not agreeing with him here, I would just like your feedback concerning this.

-Matt

[jdub]

Matt - Well you just got to experience first hand why a lot of people think a thicker oil is best. I can assure you it is not...not using a 20W-50 has no impact on developing rod knock. This guy is basically talking out of his arse

People will point at the Supra manual oil chart and tell you a 20W-50 is recommended. It is one of the oils listed, but they don't tell you it's just ONE option available. Take a look at the chart:



Note that 20W-50 is listed for a 10 to 100+ F temp range...so is a 15W-40 and 20W-40. On the 2nd line a 10W-30, 10W-40, and 10W-50 are listed for 0 to 100+ F temps...a wider temperature range. Also, if you look at the verbiage at the top, the manual shows API grades SF, SF/CC, and SG...all are obsolete API grades...you cannot even buy these oils anymore. The current API grades are SL and SM...these oils represent a quantum leap in formulation improvements over the oils available when the Supra manual was published. Modern oil's at SAE viscosity 0W-20, 5W-20, 0W-30 and 5W-30 easily cover the temp ranges (especially in cold climates) most of us operate the motor at...oils have simply improved that much over the last 20 years. Bottom line: Take the Supra manual oil chart with a grain of salt.

Your local Supra mechanic is not lying to you...he just doesn't know what he doesn't know and the previous owner of the car believed him
Here's what you hear from the guys that tell you to run a 20W-50 in the 7M:

1) The manual recommends it - False
See above. The manual does not specifically recommend a 20W-50...it's just one of the oils listed that are "approved". It also recommends a 10W-30...an oil that covers a wider temp range. Completely ignores that API SF and SG grades are obsolete.

2) A thicker oil will keep the bearings from getting hammered; provides a cushion between the bearing and crank journal/rod end - False
Main and rod bearings operate in the hydrodynamic lubrication region. I'll forego the technical explanation...think of it like a water ski. The rotating motion "floats" the bearing between the rod end and journal clearances...the bearing never touches. Almost every motor from the 1980's was designed with bearing clearances to run with an oil at 10-11 cst at operating temp. That viscosity is smack in the middle of a 30W range at 210 deg F...just below the 195 deg F the 7M is designed for.

3) A 20W-50 will increase oil pressure and keep the bearings from touching the crank journal/rod end - False
A thicker oil will increase oil pressure in the 7M, but only to a point. The design of the 7M has the oil relief valve set at 63-71 psi...over this oil is simply routed back to the pan. More importantly, the oil cooler valve on the stock filter head operates at 40 psi and you have a controlled "leak" from the oil squirters on a turbo motor. Pressure is resistance to flow...a 20W-50's increase in pressure means that it does not flow as well through the bearings or to the top of the motor. Considering a 20W-50 oil is 3-4 times thicker cold than a 5W-30, it's significant. This means a couple of things:
- On a cold start, you will have restricted oil flow where you need it the most.
- The oil relief valve will cut the flow further by opening at the higher pressure and dumping oil back into the pan.
- It will take longer for the oil to get to the cam shafts...the small diameter hole in the middle does not facilitate flowing high viscosity oil. Since the oil flows from front to rear on the cam shafts, it is going to take the #6 cylinder valves the longest to get the oil flow needed.
- The oil squirters spray pattern on the cylinder walls will degrade with a high viscosity oil...especially cold. It's simple...higher viscosity, lower velocity.
Oil pressure has little to do with the way an open bearing (like rod & main bearings) works. Like I said, these bearings depend on hydrodynamic lubrication to function...saying increased pressure will improve this is a very basic misunderstanding of how the bearings really work. The ONLY time I could see using a 20W-50 from a bearing standpoint is if you've built the motor for it by opening up the bearing clearances to get the flow...you will see some very experienced engine builders do this, mostly on race cars that get re-built every season anyway.

4) Thicker oil "stays put"...it will stay in the bearings and on the valve shims after you shut down the engine - False
When a 50w oil is at operating temp, it thins out just like every other oil does...just less so. It has a viscosity of 16-22 cst, approx 50% more than a 30W does at operating temp. This is not near enough to make the oil "stay put" when you shut down a motor at operating temp...it will drain from the top of the motor and from the bearings just like any other oil does (isn't gravity a bitch). What is important is to get oil back where it's needed, especially cold...this is where a 0W-30 or 5W-30 is far superior...much better flow means the oil will get there fast.

5) A 20W-50 handles heat better and resists breakdown - False
Any modern motor oil does an excellent job of resisting heat breakdown regardless of weight. Oil and the additives in it are very stable to well over 250 deg F...if you see those kind of temps in a 7M oil system, you have a lot bigger problem to deal with. Since a thinner oil flows much better, it also does a better job of keeping the bearings cool...another major function of oil in any motor.

The same folks that promote a 20W-50 will also say that a 0W-30 is "way too thin"...again, a basic ignorance about oil grades and what the numbers on the bottle mean. Always remember the 1st number (0w in this case) means what the viscosity is "cold" at 40 deg C...the 2nd number is what the viscosity is "hot" at 100 deg C. A 0W-30 is not thin, the German Castrol 0W-30 I recommended to you a while back is an excellent case in point...at 100 deg C it has a viscosity of 12.1 cst. A 40W oil viscosity starts at 12.5 cst on the SAE charts...the German Castrol is pretty close to a 40W oil at operating temp. The beauty about this oil is it also flows quite well cold and is Group IV PAO based...if you want to read more, I did a write-up on it in this thread, post #4:
http://www.supramania.com/forums/showthread.php?t=38768

Like JJ has told me many, many times...telling folks that a 20W-50 is not an optimum oil to use in the 7M is like "shoveling sand against the surf". The reason is what you heard from your local Supra guru...the misinformation and ignorance on how an oil works keeps getting passed along via word of mouth...mechanics are the #1 perpetuators of this myth. In all fairness, there are a very few instances where a heavier weight oil is called for...if the motor is built for it or if you already have worn bearings (just putting off the obvious here). Also, a 20W-50 is not going to kill your motor off the bat...it's also not what's best for it either. Plus, gas mileage will suffer using a thick oil. In 99% of the cases where you have a healthy motor, a 0W-30 or 5W-30 will do a better job....especially if you happen to live in the northern tier of the US or any other climate where below freezing temps are common.

I changed the title of this thread...I welcome any and all comments. Just a warning though, if you say "I've been using a 20W-50 with no problem"...my answer is going to be simple. Of course you can...it's just not what's best for your motor and you need to educate yourself as to the reasons why you use it. I base my reasons on the facts...do you base your reason on hearsay without knowing why? Might want to think about it before you respond

[jdub]

Wow, thanks for the very educated response.

I'll try to get an oil change done this weekend, with the European Formula 0W-30 if I can find it. It's at alot of AutoZone's in my area. Thanks for the write-up.

I hope that him running that thick of an oil hasn't f-ed up the JDM motor he put in it.

-Matt

Darn, all of my AutoZone's no longer carry it, what would be a good substitute?

I heard from some people that Mobil 1 10W-40 was good.

-Matt

You're welcome Matt!
Just a warning...if you hit a guy that advocates using a 20W-50 with the above info, the discussion will degrade to "well, I've always used it and in my experience its the best". Problem is, they can't tell you why...nothing to back up their reasoning other than "I've always used it" or "my mechanic recommends it" or "in my experience". I'm not discounting experience, but concerning oil there is way too much BS flying around.

A lot of AutoZones still have the GC, but it is discontinued and you'll be buying what's left. Some even have the older stuff...there's a code on the bottom that starts with an "M". The 1st two numbers are the year, the next three are the number of days into the year it was made. If it's a "M04", it was made in 2004 and it is the older "GC Green" (the oil is actually green). That is the best GC out there...made before a slight formula change in early 2005. If it is the CG Green, buy all you can get

In 2005, Castrol changed the formula slightly and removed the green dye...this is the GC Gold. It's still one of the best oils out there.

You have to go to the AutoZones around town and look...the key is "Made in Germany" on the back of the bottle. I was able to go to 4 AZ's and pick up a total of 4 cases...should last me quite a while...3 of them were the GC Green

You also might be able to get some GC at an Audi or VW dealer...it's the factory fill on those cars.

Mobil 1 is a good oil, but keep in mind it's a Group III hydrocracked dino base stock oil. If you're going to use a Group III oil, go with Penzoil Platimum 5W-30 (excellent add pack). If you really want to use a 10W-40, Castrol SynTec 10W-40 is slightly thicker than the GC at operating temp and flows quite good cold...it's actually thinner than the Castrol SynTec 5W-40. It too is a Group III hydrocracked base stock oil.

The only other "true syn oils" commonly available are Red Line (Group V ester base), Royal Purple (primarily Group IV PAO w/ ester add) and Amsoil Series 2000 (Group IV PAO based).

[jdub]

so what would be the best oil to use for a 2jz-ge overall?

Take a look at my response to Matt above...if you can find the GC, it's hard to beat that oil.

The 2JZ-GE is a NA motor, so using a true syn oil is less of a factor. You don't have to deal with the heat from the turbo. If it's in good shape, the Pennzoil Platimum would be an excellent choice so long it keeps oil pressure in spec for the motor. Otherwise, the Castrol SynTec 10W-40 would be another good choice.

well i plan to NA-T my motor with N20 later on so i guess pennzoil platinum is the better choose but later on the road for im planning on the car should i stick with the same oil?

On a turbo motor a PAO or ester based syn oil is best. That means Red Line, Royal Purple, or Amsoil Series 2000...all are available in 5W-30 or 0W-30 viscosities. If you can get a supply of the GC, it is very good. Of the others, Red Line is my 1st pick...a pure ester based oil is top of the line...can't get any better and it has an excellent add pack.

Supracentral is using Royal Purple in his Mk IV turbo with good results...look at this thread:
http://www.supramania.com/forums/showthread.php?t=41712

There's a rumor that Wal-Mart is selling RP now

You also want to use a good filter...Wix, NAPA Gold, and PureOne are all excellent choices. The Mobil 1 filters are also good, but a bit pricy...they are a Champion Labs filter with a synthetic media. If you can get them on sale, it would be fine to use. However, the others I mentioned are a bit better choices.

BTW - I'm responding this way to keep the post count down...got a feeling this thread might "blow up"

Well i found this forum that has an FAQ just on GC Oil. Pretty neat

http://theoildrop.server101.com/foru...e=0#Post711450

GC has almost a "cult like" following at the BITOG forum. Not into that mentality myself, but I know an excellent oil when I see it

Like any forum, you have to wade through the BS to get at the true info...BITOG does have a lot of very knowledgeable guys (Petrol Engineer types) as members though. Doesn't take long to figure out who knows what they are talking about

[jdub]

Pennzoil 5W-30 sounds like my best shot then, as it's available at my local Wal-Mart. However, how does it compare with the Valvoline synthetic?

-Matt

Here's the Spec sheet on Valvoline Synpower oil:
http://www.valvoline.com/products/Synpower.pdf

IMO it's on par with the Mobil 1 products. The biggest reason I like the Pennzoil Platinum is the add pack formulation...they have taken the technology up a notch for the Group III base stocks in the past couple of years.

So do you think the previous owner has caused damage to my motor by running that thick oil?

-Matt

I doubt it. He just wasn't doing the motor any favors.

[jdub]

I've been using a 20W-50 with no problem...or is it 5W-20? Doesn't matter. Oil is oil right?

So this guy thinks not using molasses leads to rod knock. That's a hoot. If he had any sense he'd realize it's closer to the other way around, especially when combined with cold start up temps.

LOL! That statement (not using a 20W-50 causes rod knock) is exactly what set me off on writing another novel on this subject. It's just sooo wrong for so many reasons. Just could not let that one pass...I guess it's my mission here to shoot that kind of total ignorance down.

Yeah...I know...where's my shovel?

BTW guys - JJ is running Pennzoil Platinum 5W-20 in his 7M and summer is just around the corner
So far with great results.

[jdub]

John, I'm going AutoZone raiding when I get off of work. Do you recal off the top of your head if the "M" label was on every bottle (on the bottom right?) or was it just the boxes that they were shipped in?

It's on the bottom of every bottle...some of the early 2005 codes are also the GC Green. The best way is to open one and pour a little into the cap...it's green alright

In any case, the GC Gold is very good...I'd buy it in a heart beat.

Looking for a 0W-30 that would be an equivalent to the German Castrol?

Brad Penn makes it... and here is their link.

http://www.bradpennracing.com/Products/racingoils.html

It is known as "The Green Oil."

Well...not exactly "equivalent". Here's the data sheet for the Penn Racing Oils:
http://www.amref.com/bp_pb/7115_17_1...ng_Oils_PB.pdf

This makes the Penn oil a blend of Group II or III base stock with either PAO or ester as the synthetic component. German Castrol is a PAO base stock oil with some esters as part of the add pack...100% synthetic. The data sheet alludes to an API SJ rating, but I could not find it on the website. It is green though...perhaps the same Black Forrest elves had a hand in making it? LOL.

It looks like a strong add pack. ZDDP is Zinc dialkyl dithio phosphate, a family of zinc salts of dithio organophosphates...it is the dominant anti-wear agent present in motor oils. Soluble moly is the other most common anti-wear agent. GC contains both ZDDP and moly. Usually the amount of ZDDP is minimized in most motor oils you see on the shelf due to the zinc and phosphorus emissions damage potential to catalytic converters. This oil may just have a bit more healthy dose. Plus the sheet says it has a strong dose of detergent and dispersant additives...something you normally don't see in a racing oil.

The cold/hot viscosities look good, especially the cold viscosity. The only thing I can see that's a bit odd is the flash point...it's low for this kind of oil. Leads me to believe Penn is using low viscosity Group II cuts to make the "0W" part of the viscosity grade. This could very well impact NOACK Volatility which determines how much weight loss an oil experiences through volatization. Meaning, you may experience higher than normal oil loss due to vaporization over time.


Give it a shot. Do a virgin oil analysis (VOA) and used oil analysis (UOA) at the 4000 mile point and post up the results.
You might just have a winner

[jdub]

a good place to use 20w 50 is if you have a stubbon oil leak on and ol engine or shitty valve stem seals. Since when the oil cools it becomes thicker and tends not to leak as much.

Also I used to use 20w50 only in the summer... I liked the added heat protection as I often forgot to turn on my elec fans until i hard wired them to the ignition.

Don't you think it just might be a better idea to fix the cause of the leaks?
Of course, on a old motor it really doesn't matter...might as well hasten it's demise and put it out of it's misery.

I would like to know one thing though...how do you figure 20W-50 gives you added heat protection?
Your mechanic tell ya that?

Well since in live in az. The temp here is like 100 at night and 115-120 in the day in summer would a thicker oil be need then? BTW this is for a 5m-ge. Also would 20w-50 be better is your car burns oil very badly my freinds honda burns like 8 quarts per tank of gas which is like 10:1 oil to gas ratio lol.

If you take a look at any oil data sheet, the "cold" viscosity is rated at 40 deg C...that's 104 deg F. In AZ, all that happens is it just takes the oil less time to reach operating temp (100 deg C). It also points out the need for a good oil cooler in this environment. BTW - I live in Phoenix myself

Let's use Mobil 1 EP as an example. The 5W-30 has a viscosity of 61 cst at 40 deg C...the 15W-50 is 138 cst at 40 deg C. That's over twice the viscosity at engine start...in cooler climates, the viscosities are even higher with a bigger difference between the grades. Take a bottle of each oil and put it in the freezer for an hour, then pour side-by-side on an inclined cookie pan...the difference in viscosity will become graphically evident.

Once the oil is at the 100 deg C ops temp, the viscosities drop significantly...the 5W-30 is 11 cst and the 15W-50 is 18 cst. Still quite a bit of a difference, but less impact on oil flow through the engine vs. cold. Here lies the problem...the time it takes to warm up the oil is cutting oil flow through the motor. This is not doing your bearings any favors. Also, engines from the '80's were designed to run at a viscosity of 10-11 cst hot...that includes the 5M.

I run a 0W-30 all year in Phoenix...I also have a cooler that's twice the size of the stock one. If your 5M has a lot of miles on the engine, a 10W-40 may be more appropriate due to bearing wear already present. I would never use a 50W oil unless I built the motor to handle it.

Concerning your friend's Honda...his motor is FUBAR'ed. There is no oil or "magic additive" that will help...he needs a new engine

[jdub]

Please tell me people DON'T actually think a thicker Oil will leak less in a leaky motor........

IJ - sad as it may be...people think that exact thing. The above posts are a case in point....it's just not true. Thicker oil will not stop a leak. Fixing the seal, gasket, or O-ring will though

[jdub]

Beeing a noob concerning oils and finding the infomation in this thread a great find, I got a question concerning Mobil 1 5w50 or Castrol Synth 5w50. I'm in eastern Canada where the weather gets a mighty cold, but my Supra never sees a snowflake in winter, the car hits the storage garage from November to May. The coldest it will see is maybe 40F overnight during a late fall event but summer temps can rise to 100f and a spirited ride can show 210 on the aftermarket water temp gauge.
On the first day of storage after riding the car to get it to opperating temp, I do a oil / filter change and put in a 5w50 from one of the above brands. At least once a month I spin the engine to lubricate it (do not start the car, just spin the engine until I see pressure on an aftermarket gauge).
I, too, was under the influence of word of mouth that a w50 oil would be better for a car that sees extended use (taxi or such) in hot weather. My experience here is that while I used to drive a Honda as a courrier, and while doing an oil / filter change every 2 weeks, I found that cheap oil always (Esso / Shell / No name brand) used to get used up quickly in the honda moter while brands like Castrol or Quaker would stand up and not "dissapear" from the high milage / long day usage engine. Hey, it is only an experience, there is no facts like you guys supporting the above.
Other than the above recommeded GC and Pen oils as well as RP, etc, do the Mobil 1 and Castrol Synth stand up to the test? After reading this and the other Oil post, I am thinking of moving down to a 5W30 or even the 0W30 GC (found some at Walmart).
Any info on the 5w50 oils is welcome.

Mobil 1, Pennzoil Platinum, and Castrol SynTec are all Group III oils...extensively hydrocracked dino oil base stock to be precise. Group III by definition is not a synthetic oil...the companies get away with marketing it as such because they use "synthetic technology" to produce the base stock. Group IV & V are the synthetics...PAO and ester are the most common. These are Amsoil, Redline, GC, and Royal Purple. I'm not saying the Group III "synthetics" are bad oils, they just are not true syn oil and paying a syn price for them is, well, unsat.

Any oil with a big viscosity spread (like a 5W-50) requires a lot of viscosity modifiers for it to perform to spec. That means there is less actual base stock oil by volume to actually lube your motor. It also makes "viscosity creep" much more likely....viscosity modifiers are one of the 1st things to degrade as the oil goes through heat/cool down cycles. The viscosity will move toward the base stock viscosity...in a 5W-50's case that will be toward the high end...it will lose the ability to act as a 5W when cold. BTW, Group IV & V oils do not require as much viscosity modifiers to perform to grade.

All of the above Group III oils are very good...the Pennzoil is my choice due to the advances they have made in formulating this type of oil. All can go 5000 miles between changes with a good filter. They are not in the same class as the Group IV & V oils though...since you can still get the GC (it's at Canadian Tire too), it would be an excellent choice...especially for your climate.

I'll throw something out concerning storing your car for the winter. I would change the oil to a decent 5W or 10W-30 dino oil (Wal-Mart SuperTech oil and filter), drive it for a week and put her up for the winter. When you're ready to play for the summer, change the oil to GC, use a PureOne or Wix filter and you will be good until November (assuming 8-10000 miles). If you hit the 4000 mile point during summer, change the filter and add enough GC to make up.