10w-40's & Semi Synthetics; unloved children?

[2000wrx]

Since discovering this forum some months ago, I have noticed that with a couple of exceptions, no-one seems to like 10w-40's or semi synthetics. Why? Surely some synthetic is better than none synthetic. Is it just the price?, cause in Aus we can buy semi-syn for just a bit more than dino. Also no one seems to have a problem with 15w-40's or 5w-40's, but 10w-40, no-one likes the middle child. Its not as wide a spread as 5w-50 or 0w-40. Surely it should be possible to make a very robust 10w-40. It is one of the recommended oils in my 2000 WRX.

Also I mostly drive my car 3 times a day on a 2 mile trip on weekdays, and on a fairly brisk 1 hour drive on weekends to boil gunk from the oil. Winter here is as low as 32f and summer up to 100f. Has anyone a rough guide, as to how many months Delvac 1 will last under these conditions. It would not see Subaru's 7500mile limit in 6 months.

 

[lyle]

Motorcraft 5W-20 and 5W-30 is a semi-syn and many people think very highly of it. Even if they were priced higher than ~$1.50/qt people would still buy and use it.

 

[sgtgeek]

I wouldn't put anything other than Synthetic Amsoil 10-40 in my modified LS1. She runs quieter...dyno'd better...and temps are great....most of the LS1 "beast" I hang out with all use either a straight dino 10-40 or a blend of synthetic 5-30/15-40.....I agree with your observation...there seem to be some that frown on the 10-40....I cannot answer that question of "why"...I can however attest to the facts of my motor and it's like of 10-40.

[ January 29, 2005, 09:47 AM: Message edited by: sgtgeek ]

 

[TallPaul]

I used seim-synthetic Valvoline Durablend for about 4 to 5 years. Currently have a stock of 10w40 Durablend and Maxlife (which could be considered a weak semi-synthetic with its 15% PAO). You also can make your own semi-synthetic by adding say a quart of Mobil 1 or Redline to a fill of dino.

BTY, you might enjoy this interesting thread from last year titled, 10w40 Gets a Bad Rap.

 

[Pablo]

We only attack perceived weaknesses....some 10W-40's (and 5W-30's) over the years have been weak.

"semi-syns" because people kinda like to know what they are getting: discussion

 

[jsharp]

I'm using Motorcraft 5W-30 synthetic blend in our Pathfinder now and I'm going to try Schaeffers 5W-30 7000 blend in the truck next.

As far as using a 10W-40, I mixed 1/2 M1 5W-30 and 1/2 M1 15W-50 for use in my generator. Does that count?

 

[KW]

I'm using Amsoil 10W40 in my little 1994 2.5 Dodge Shadow and have no problems with it so far. I had HD30 in it for an ARX rinse and it was a little hard to turn over on a couple of 10 and 12 degree mornings. Now with the 10W40 it spins over like it is warm compared to the 30wt.

The reason for the 10W40 is that the motor is a little tired at 117K and I have plenty of the 10W40 around for a couple of motorcycles.

 

[ZR2RANDO]

The main drawback of the 10w-40 oil that I have learned is that it requires so much more of the VII than the lower spead oils do. The VII is the weak point- it breaks down over time (leaving residue) and the oil then behaves different after xxxx miles than it did when new. I understand that the materials used for VII now are more heat stable than they used to be though..
Short/normal OCI like 3k probably no problem, but longer intervals or engines with overheating issues should probably use other stuff...most mfgrs don't want folks using it in newer engines (under warranty) but not all of us have new engines..my newest one has 83k miles on it, and I'm not getting rid of it anytime soon..
Most of the 15w-40 diesel rated oils out now seem to be pretty hard to beat too.
Anybody else agree/disagree?

 

[RJCorazza]

I use Amsoil 10w40 in my BMW bike for winter use, in our 'beater' 145k GrandAm, and in my lawn maint. engines.

Current synthetic 10w40's use little or nor VII's to break down. Back in the 80's 10w40 oils pretty much got a bad rep for breaking down quick and folks don't forget that easily. I would venture to say that the dino 10w40's are significantly better oils than they were 20 years ago.

 

[Anthony]

Mobils new extended performance 10w40 synthetic will probably be very good.

 

[jbas]

Recently the new "synthetic blends" offered by Motorcraft, Mobil Drive Clean, and Phillips Trop-Arctic, have received much positive discussion, especially in light of their WalMart prices ($1.52, $1.17, and $1.12/qt, respectively).

And I used and liked the 10W-40s of the 80s and 90s, even though I drove in true subzero temps in upstate NY. I never walked lockstep with GM...in my way thinking, if they can't build the best quality car/truck, who were they to advise about lubrication?

 

[brian fix]

the new age 10w-40 lubes may and most cases are a step ahead of older formulations ,even 5 years ago,the use of more modern bases and vis improvers,adds ,a good example is Mystic,10w-40 with its specs,and of course cost$,or even Pennsoil,, the adds companys can also advise the improvements ,they are a much more stout lube than past,per application...BL

 

[radiometer]

Recently I switched my 99 Nissan Sentra from Schaeffer's 700 15W-40 Blend to Castrol Syntec 10W-40 (vis. 13.2 @ 100C). I immediately did not like the metallic noise that sounded out with the Syntec at cold start-up. When the engine warms up it is then silent the rest of the day. I fully realize this does not mean the Syntec isn't a very fine product. I'll try some of my stash in my other car and see how it works there.

In the meantime, on a very short OCI of about 1k miles I drained the Syntec and refilled with Schaeffer's 15W-40 (vis. 15.0 @ 100C). I didn't even change the filter this time although I drained it. This gives me back my much quieter cold start-ups.

I intend trying the Schaeffer's 9000 5W-40 when it becomes available in quart or gallon sizes. I'd like to see how it does in this car.

 

[ruking77]

In the USA, 10w40 used to be the "standard" but actually that was a very long time ago. The real standard has been 5w30, since at least 1986 that I remember.

If you are a 10w40 user then I would probably go to Delvac One 5w40 aka Mobil One Truck & SUV. I use it in (TDI) turbo diesel application and would not hesitate to use it in back fill (higher cost per quart than 5w30) for LS6 (Chevrolet small block V-8) Toyota Landcruisers. I am guessing your Suburu is a turbo also.

In regards to semi synthetic, I would just blend it myself. If you use 1 qt of syn per 4 qts of conventional, you instantly have a blend of 25%. This is 5-15% more than the semi syn you can buy off the shelf.

 

[Bob Miller]

My Honda Prelude has 230,000 miles on 10W-40 and still burns no oil.

Nearly all on Valvoline and currently using Maxlife.

 

[Gary Allan]

quote:

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no-one seems to like 10w-40's

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10w-40 in a dino is a mostly un-needed grade. If 10w-40 didn't require the tweeking to meet the 10w spec ..then I would suspect that your HDEOs would more than welcome the added cold start spec. They don't and 15w appears to be the industry's limit on making this stuff in a robust formula that can go the distance without side effects. That's in a dino mind you. 25 years ago, fleet weights (they're still available) were 20w-40. No one spec's a dino 10w-40 anymore.

If you can use a 10w-40 dino..I don't think that it's too much of a stretch to 15w-40 (which has a contemporary use and spec).

That's not to say that you can't use it and have good results with it ..just that the two principle markets have sorta bypassed to either side of it. The locals that I see using this the most ..are the weekend/good weather street rodders. They're changing their oil like they do their socks anyway. I could also see this in something like a motorhome type application. Limited mileage... severe duty..where the service demands a 40 weight, but the specific use doesn't include "economics" into the equation.

quote:

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or semi synthetics.

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I have never used semi-synths since I've always used full syths (or psuedo full synths). The only use of semi-synths for me is when I bought MC 5w-20 for use in my daughter's Taurus. Other then that, it was the cheapest 5w-30 dino avaiable. If I couldn't get extended drains out of it ..why would I bother with the added expense ..at least within those limited conditions (excluding severe climate, etc.)??

 

[Mickey_M]

quote:

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Originally posted by jbas:
The 2004 Kia/Hyundai 3.5L, V-6 recommends a 10W-40, or 10W-50, in hot climates. I'm guessing the 2005 models do too.

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I'm having some problems confirming that it's a recommendation.

Mobil's website lists nothing with a higher SAE viscosity than 10W-30 for any Hyundai under any use.

At

http://www.hmaservice.com/webtech/default.asp

for the XG 300 2001 and XG 350 2002-2004, which uses the 3.5 V-6 engine, it looks like higher viscosities are usable, over 90 F or so, but that's not a recommendation. It's a statement that higher viscosities are usable, which is absolutely true.

A 0W-40, 5W-40, 10W-40, 15W-50, or 20W-50 is usable in many vehicles at very high temperatures.

Hyundia recommends a 10W-30.

 

[2000wrx]

Mickey_M

My 2000 WRX manual specifies SJ certified 10w-30 or 10w-40 oil. Not a new car anymore, but pretty close. While Im guessing its not severe on its oil, it must stress its 4.5 litres of oil somewhat with 110bhp/litre on a 95F day.

 

[Gary Allan]

Well ..let's split the hairs here.

99.999999% of all cars sold in the LARGEST auto market in the KNOWN UNIVERSE don't spec 10w-40 for anything with 4 wheels driven with a normal license.

Anything that typically spec's anything with a "40" on it ...also specifically spec's a synthetic as well (as in your Euro types)

Very obscure and extremely limited exceptions apply.

 

[jorton]

I think the current api certification has brought new semi-synthetic labeling to some hydrocracked dino formulas.

I thought this topic refered to the oils labeled synthetic blend that have been available for several years. Those aren't very popular and now they compete with high mile formulas in the same price range. So synthetic blend popularity will probably decrease more.

I would choose 10w-40 if I noticed a psi drop on a good oil pressure gage. Other wise use the lightest grade that gives 10 psi/1000rpm, plus 10. 20 or 30 wt usually gives that.