Hmm dont flame me but...

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Sep 20, 2002
New York, NY

I dont mean to sound unsupportive or anything but,
I am reading about folks seriously considering 20 weight oils.
Why would anyone ever run a 20weight oil in automotive application?
Regardless what the manual says, we all know why the manual say that, it has been covered here before and has nothing to do with engine protection.

Even in the middle of an Minnesota winter there are better oils there (0w-30,0w-40).

I wouldn't take a 20 weight oil even it was free PAO.

So far we just don't know but your right, it really all comes down to fuel ratings. IMO, there are better ways to do this then making lighter oils. I've been batting this "Flow" idea around that a Bob mentioned and it makes sense but I'm not so sure it really applies to all engines. I think in engines with tight tolerances, like Honda's and Toyota's, it's fine. However, in Ford trucks and other V8's like Patman has stated with larger tolerances, I would not run a 20wt. oil. Does anyone know if you really void the warranty if you don't use the recommended 20wt. oils? I had Ford put Amsoil 5w-30 in my wife's Focus and they had no qualms with it.

BTW, one of Amsoils engineers/managers said they don't make a long drain 20wt. because of low sales and they aren't too thrilled of the idea of a 20wt. oil going 25k miles. His words were "gut wrenching" to think of a 20wt. oil thinnning down slight and still doing it's job.

[ April 18, 2003, 06:52 PM: Message edited by: buster ]
In my Escape's warranty book it's spelled out in pretty easy to understand terms that use of an oil other than the recommended 5W20 will void the warranty. Aint no if, ands or buts about what I read.
Fred, you make a good point and I struggle with this concerning my 2002 3.0L Ranger. There is conflicting info as to weather or not using a 30 wt. can void the warranty. The bottom line to me is, Ford can afford to deny a claim if my motor goes south, I cannot afford to replace an engine or be without transportation during a legal battle. So I will use Castrol 5w20 for at least 36,000 miles. I doubt it will hurt the motor, especially in 3,000 mile intervals.
Buster ,I have to mention tolerance is an allowable variation of specification . We mean small clearace or tight clearance .Then all that is needed in an oil as to viscosity is to keep the parts apart.
I still find it funny how people think 5w20 oil is so super thin and they'd never run it in their cars, but they'll run Mobil 1 5w30 and not think twice. Mobil 1 is almost a 5w20 right out of the box (it's only 0.4cst thicker than the cutoff for 5w20) So what is the problem with running a 5w20 if it's 9.0cst and stays there? A 5w20 can be made to be more shear stable than 5w30. What is the difference if you get a 5w30 that starts out at 10.0 cst and thins down to 8.8, or if you have an oil that starts out at 9.0 and stays at 9.0?

I'm not saying to run 5w20 in everything, but if I had a new car which called for it, I'd use it for a little while and let the UOAs decide for me. So far the UOAs on here for 5w20 don't make it look like this oil is going to cause engine failures. So for those of you who need to run 5w20, run it for the first year or two, do UOAs on it, then go up to 5w30 and see if the wear numbers change.

I would never consider a 5w-30 either.
Again, better oils bracket it on both ends.

If start up is a concern, a 0w-30 is what I would use (but not a MOBIL 30 as they spec out so thin).
Or maybe a MOBIL1 0w-40 (which I currently run and it outperforms a 5w-30 from same manufacurer on both ends of the spectrum).
There are many good 5w-40 available too w/ similiar start-up abilities to 5w-30's but better film strenght.

All the above is comparing weight of same manufacirers against each other.

As for "tighter clearances" in modern engine that just doesnt hold any wayter as clearances have more or less stayed the same for most applications.

Also Of course the same engines that in USA are often recommended 5w-30 or even xw-20 are recommended xw-40 in Germany, Australia and Japan.

If you go back to the 80's u will find that teh 2.8 L Inline 6 are recommended by temp range from 5w-30 (thick of northern winter) to 20w-50 (southern summer).
The last couple of years that (nearly ) exact same engine was offered in USA it was recommended 5w-30 year around!!!!!!!

Obviosuly the engine doesnt actually change magically as it crosses the Atlantic.

As for warranty voiding:
Its teh API service requirement that needs to be met bu an oil that you use aftermarket, I admit I ahvent read fords wording (could u scan it for us?) but all otehr manufacturers make recommendations based on viscosities, and dictates only with reagrds to the rating (such as SL for current model years).

If Ford takes it one step further I'd be interested to see it.

Also in recent years the first few unusual engine failures in hi performance engines have cropped up (not just in M3) and low and behold all those engines used to have 40 or higher recommended and now recommend 30 weights.

there is esoecially need now than in previous yeras to got o thin oils because we now have acces to 40 weight oils that flow better than outright winter oils of 20 years ago.

My old (83) Saab Manual btw says: Do not run a winter oil such as a 20 weight oil at extended hiway speeds even in winter.
In those days they recommended 40 +50 weight in summer, or 40 weights in mild climates year around (10w-30 were "acceptable" as well).

And now low and behold the last few years of production of that engien recommended 5w-30 yera round with no significant change in the engine.

Hence the "we recommend thinner oils cuz newer engines are tighter" arguement manufacturers field is simple disinformation.


Originally posted by Jay:
palmerwmd, what is your experience with 20-weights?

I dont have any, cuz my engines are too dear for me to ever buy gamble on them for no reason, I really dont care one bit about fuel economy either.

I run 0w-40 Mobil1 now, used to run 5w-40 SynPower.

Anecdotal personal experiences whether good or bad w/ 20 weights, wouldnt change the nature of the discussion.

The only time 20 weights were ever acceptable before, was to make a good start-up possible in northern winters.

As we can now make similar or better, start-up happen with xw-30 weights or even xw-40 weights nowadays, the 20weight oil in automotove applications has no justification at all.


[ April 18, 2003, 09:06 PM: Message edited by: palmerwmd ]
Fred, have you spent time looking at the 5W20 UOAs on this forum?? If you look you will see that there have been some pretty good results with 5W20. Remeber, it is wear that matters with oil, so as long as 5W20 provides low wear in an engine, what's the problem?

I used to be skeptical until I started running it in my sister's 2003 Civic and saw some good wear numbers from the oil, and other UOAs on this board. -Joe

By the way, are you experiencing the dreaded 3.0 spark knock that may Ford Rangers and Mazda B3000s experience? My 2000 B3000 knocked like crazy, no matter what grade of fuel I put in. After new knock sensors, a new computer, and new MAF, it still knocked.

Buster ,I have to mention tolerance is an allowable variation of specification . We mean small clearace or tight clearance

Your right. I meant clearances. Steve couldn't tolerate my misuse of words.

Patman is right that Mobil 1 is almost a 20wt oil. It is though, a high low 30wt/high 20wt. M1 0w-20 is around 8.3 or so based on there latest spec. sheets, making it a middle/upper 20wt. This oil being only a 20pt spread will stay put so thinning is not an issue and it should hold up well. Mobil's 5w/10w-30's are shear stable so these are fine too. Again it comes down to the engine and how the car/truck is used. If you have an Ford pickup that calls for a 20wt. and you pull a trailer during the hot summer months, would you still use a 20wt.? Maybe, it depends on the analysis but I personally would not. If engine clearances havn't changed and the rest of the world, like Europe for example, goes with heavier oils and 10k+ drains, I'd rather go with a heavier oil for the longe hall. For 3-5k mile drains under normal driving conditions, I think these 20wt.s will hold up fine.

[ April 18, 2003, 10:00 PM: Message edited by: buster ]
Joee, I'll jump in on the 3.0 question because my 2002 Ranger is my third in a row with the 3.0 V6. My first two ('92 and '97) sounded like marbles in a coffee can on anything less than 89 octane when pulling a hill. This '02 is great, I have run strictly 87 octane for all 15K miles of its life and very little noise, even pulling hills. I just love that reliable little pushrod motor!

Fred, what part of Louisville? I lived briefly off Breckinridge while training for my company years ago and our division offices are on Linn Station Rd.
My thinking is that if a 20-weight oil protects well then why go heavier? Regular gas costs more than $2./gal in my area. I care about gas mileage.
There are too many good 20-weight UOA reports on the board to ignore. These aren't anecdotal evidence.
If there was such a thing as the internet back in the 60s and 70s, we'd be all on here saying "darn those 10w30s are much too thin for our engines, they are all going to die an early death, I'm sticking with the thicker oils" But yet 10w30 proved to work out very well. I'm confident we won't see engines dying due to 5w20. Oils are getting better and better all the time, and it's possible to build a 5w20 which protects like a 5w30 (just look at Redline's 5w20 specs for instance)

Heck, even Metroplex mentioned in another thread that he's thinking of using 5w20! I never thought that was going to happen!
im running it in my 02 civic ex 5spd, and its holding up fine(castrol gtx 5w20) at 4100 mi and still hasn't turned dark yet. Ill probably be changing my oil over in the next 3 weeks to mobil 1 0w20 when it comes out. I think 20 wts are suitable for 4 cylinders and small 6 cylinders. However, if you have a big v6 or v8, then i would never run a 20 wt unless it was something like mobil 1, redline(moly, moly, moly), synergyn, or amsoil(if their 5w20 was still group 4).
This SAE 20 thing is not new at all. American cars from the 1950's used it. The owners manual for my 1957 Chevy calls for 20W-20 as the primary recommendation. The heavier wieghts really became popular in the '70s due to the higher temperatures in emission-controlled engines.
A lot of people think that Ford and Honda went to 5W20 oils just to raise their corporate CAFE. A friend of mine bought a new Honda Civic and 5W20 is required, but 5W30 is allowed if a person cannot find 5W20. Those are the only two weights mentioned in the owner's manual. According to what I have heard, 5W30 oil requires more viscosity improver than 10W30. I think that synthetic oils will be the answer when all vehicles require extremely light weight oil. But the question is-do those new Ford and Honda engines really have such tight clearances that 5W20 weight oil is necessary, or are they going to 5W20 weight oil just to raise their CAFE? There was a somewhat similar situation involving Saturn cars. The engines were basically the same for many years, but when I bought my first Saturn, 30 weight oil was allowed in the summertime, along with 5W30 being the preferred grade and 10W30 also being allowed in warmer weather. With the Saturn I have right now (with basically the same engine), 5W30 is the preferred weight with 0W30 allowed in the wintertime and 10W30 allowed in warm weather. 30 weight oil is not allowed. Did Saturn really tighten the clearances in the same engine?

A lot of people think that Ford and Honda went to 5W20 oils just to raise their corporate CAFE

Mystic, the general consensus is that 20wt. oils are out due to CAFE ratings, nothing else.
You can make just about any engine work with 20wt oils by adjusting the oil pump output, the load supporting area of the bearings and going to roller rockers for the valvetrain.

New BMW oil specs for 2000-2003 engines:

Synthetic oil meeting BMW Longlife spec:

All temps: 0w-20/0w-30/0w-40/5w-20/5w-30/5w-40

Need I say more?

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