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Oil for '07 Cadillac STS

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Hi, I was wondering what kind of synthetic oil I must use for my Cadillac, perhaps this is why I have car troubles. And what oil viscocity (5W-"something" or 50w-"something") should it be and what other oils am I capable to use?

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5W-30 Synthetic. Oil must be formulated to meet GM standard GM4718M or Dexos1 (superceeds 4718M) so anything that meets dexos1. 0W-30 is acceptable in cold climates.

Do not use any other viscosities such as 10W-30, 10W-40, 20W-50

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the factory recommended oil is printed on the oil fill cap. they recommend mobil one 5w30,but as z15 stated, any full synthetic that meets the factory standard in 5w30 is acceptable, I run strictly royal purple 5w 30, but that is just a personal preference.

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On September 30, 2013 at 6:09 AM, Z15 said:

5W-30 Synthetic. Oil must be formulated to meet GM standard GM4718M or Dexos1 (superceeds 4718M) so anything that meets dexos1. 0W-30 is acceptable in cold climates.

Do not use any other viscosities such as 10W-30, 10W-40, 20W-50

To some degree I would concur, at least on the heavier viscosities.  But not a 10w30?  Quiz question:  what is the kinematic viscosity at 100c (read that as the operating temperature of the engine) of a 5w30 vs a 10w30?   Answer:  The same!  At operating temperature, 0w30, 5w30, and 10w30 all have the same kinematic viscosity of around 10.5 to 10.9.   The only difference between them is the winter cold flow rating, which is what the "w' stands for.  And that has more to do with cold starting than running the engine.  The "w" is not a oil weight rating but a cold flow rating.  Go to the SAE website and they will confirm this.  And even then, unless one is dealing with some serious nasty cold at start up, it is not really an issue. Michigan gets cold, but not real nasty cold except in the U.P.  (yes, I travel Wisconsin, Minnesota, Michigan, etc frequently year round). A 10w30 full synthetic generally will have a -40F to -45F cold flow pour point along with a rated cold crank start rating of -25F to -30F.  So unless one is in Calgary,  MT, ND, or Fairbanks, AK type of weather, a 10w30 will be fine. For those like me, that the car resides in a heated garage when not in use, a 10w30 will work just fine year round.  It rarely gets below -20F in my area in Central Iowa.  I lived outside of Fairbanks, AK for 10 years and used 10w30 conventional with no problems. But then, we were smart up there... we had block heaters, oil pan heaters, and electric battery blankets that all got plugged in when the vehicles were at home.

 

That all being said, everything from my Yamaha portable generator on up thru my class 8 commercial trucks all get 10w30 oil.  Different types, but still 10w30.  My 2015 2500HD, my 2006 CTS, my JD zero turn mower, my JD 825i Gator, my ag tractor, my 2013 Freightliner semi trucks.   10w30 has a lower volatility rating (NOACK vaporization rate) than either 0w30 or 5w30, it also uses less viscosity improvers which can shear under extreme pressure, and it maintains a more level viscosity rating over the entire oil change interval.  Many full synthetic 10w30 oils are actually straight 30w oils, but qualify due to their cold flow rating as 10w30.  I have long since become very fond of 10w30 oils for all these reasons.

And most full synthetic 10w30 oil will meet GM 4718M and 6094M specs, which are the basis of what dexos1 is built upon. The dexos1 spec just specifies a 5w30 minimum to cover all the bases of what most folks deal with in N. America.  In some ways, it is not even as good at ILSAC GF-5 rating, which has a better ethanol emulsification spec than dexos1.  Which seems strange, since GM is all over the idea of using ethanol.

Edited by Cowpie

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I usually don't get involved in oil debates and especially not in brand debates.

I agree with @Cowpie and @Z15 with the exception of the statement "Do not use any other viscosities such as 10W-30, 10W-40, 20W-50s", they have their uses especially in high mileage engines. Cowpie brings to light one of my pet peeves about the misconception of the W rating. Good job Cowpie !

The importance of oil as it relates to Cadillac in particular, and specifically the older engines is the shear capabilities of the oil and also the Zinc content. Particularly, the NStar is a flat tappet over-head camshaft engine that creates different stresses on oil than roller or traditional type lifter engines, except when you get to the extreme levels of valve spring rates. High Zinc content oils are the best for wear protection but Zinc shortens the life of catalytic converters. High mileage brings the need to "fill" gaps in bearings, lifter bores, etc. into the equation so in some applications higher viscosity oils are extremely helpful as are oils that may not be "recommended", such as using "diesel" engine oils in gasoline engines.

Most all of the auto manufacturers choose a "middle of the road" oil recommendation and Cadillac is no exception. In conclusion, oil viscosity in my opinion, depends on the temperatures the engine is subjected to on a regular basis, mileage, driving habits, so on.. 

i highly recommend reading the oil manufacturers product content information, and the oil industry specifications then decide for yourself, it is ultimately a personal decision. 

Regular oil changes are the best insurance against wear and premature failure, but that is another topic altogether.

Disclaimer: Yes, I do realize you do not have the NStar engine. Using it as an example only.

Edited by OldCadTech

THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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My recommendations were based on the owners manual for the car and 5W-30 is what it calls for.   At the time of the post no 10w-30 met GM4718M (superseded w/dexos1). only 0W-xx and 5W-xx do.

 

Quote

Synthetic Oil Question

We recently received this e-mail from Mike McQuoid, at Norman Gale Pontiac GMC, Cedar Knolls, NJ:

“In the March 2005 issue of TechLink, there is a list of motor oils approved by GM for use in gasoline engines. I'm curious why so many “full synthetic” oils are listed in the “non-synthetic” list and not in the synthetic list.”

Here’s the answer from GM Powertrain:

“GM4718M is General Motors' High Performance engine oil specification. Oils which meet GM4718M tend to be made from synthetic base stocks, so it is often referred to as a "synthetic" specification.

“However, not all oils, synthetic or otherwise, are capable of meeting the stringent requirements of GM4718M. Only the oils listed on the GM4718M Registered Products sheet have proven their performance to the specification.”

- Thanks to Matt Snider, GM Powertrain

 

Edited by Z15

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@Z15 I didn't realize the date on the post was 2013, until you said that :) 

Your recommendations are valid, I never thought they weren't, it's that in some engines, the other viscosities serve a purpose as well, even though they weren't or aren't the recommended fluid.

 

 


THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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dexos1 is the latest GM standard, and it is good, it is built upon 4718M and 6094M.  But it falls behind ILSAC GF-5 in dealing with ethanol, and considering that almost everyone uses E10 nowadays, by choice or not, and GM encourages its use, they dropped the ball on the dexos1 spec in this regard.  This is why I don't really worry too much about dexos1 spec, even for my 2015 Silverado 2500 gasser.  And there was a TSB out not all that long  ago that stated API SN synthetics could be used in place of dexos1.  So, GM doesn't have a real big issue with SN, ILSAC GF-5 is better than dexos1 for ethanol, so I just select 10w30 oils that meet SN, GF-5, 4718M, and 6094M and call it a day.  10w30 will never meet dexos1, but that is only because dexos1 requires a 5w30 or 0w30.  Just because such a low cold flow is called for in the spec does not mean that it is needed across the spectrum for all applications.  For that primary reason, I don't use a dexos1 oil.  I prefer the better characteristics of 10w30 over 5w30 and 0w30, and I don't live in Alaska or run the ALCAN highway in winter, so I don't need the cold flow of a 5w30 or 0w30.

But in reality, whether it is a synthetic, a blend, or a conventional, it is the additive package that makes up 20% or more of every quart that make a significant difference.  Zinc was mentioned, it is a good extreme pressure additive, and yes, it has been reduced somewhat in the latest spec oils because of emissions stuff. But molybdenum disulfide (MOS2) in conjunction with boron (boric acid) does a darn good job as well and doesn't affect catalytic converters and such.   I prefer oils that use generous levels of moly and boron in them.  The best way to learn what comprises most oils on the market is to take a stroll over to the Petroleum Quality Institute of America website and take a look at the testing they have done on a lot of oils.  They break it all down and show what they are made of.  While base oils may be similar, the additive packages are all over the map.  And yes, even among dexos1 certified oils.  Dexos has certain requirements, but after that, the blender can pretty much play fast and loose with additives at their discretion.  And some really don't put a lot of emphasis on extreme pressure protection and friction modifiers, while other blenders take it more seriously.  There are mediocre dexos1 rated oils that just slide in under the wire regarding dexos1 compliance (and I wouldn't let them near my engines), and there are some pretty good ones that exceed the standard.  But likewise, there are some non dexos1 approved oils that put some dexos1 oils to shame and meet or exceed the dexos1 standard.  Usually the market focus it different, so they just don't bother with seeking dexos1 official certification.  It is fee based and can be costly unless there is significant volume to overcome the initial and ongoing fee structure, so some don't feel spending the money for dexos1 approval is worth it.  GM is the only entity that charges for oil certification.  API doesn't, ILSAC doesn't, and the European oil standards do not require fees.  And some of the EU standards are tougher than dexos1.

Edited by Cowpie

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Good information @Cowpie - It appears you've been keeping up on it a lot more than I have.

There was talk about high temp - high shear mods so a switch from ?W-30 to a ?W-40 would provide increased oil film thickness at !00C . Is that the MOS2?

Don't know if I want to keep up on that stuff anymore anyway. Makes my head hurt now LOL


THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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LOL!  MOS2 is molybdenum disulfide, what most would simply call Moly.  It has some very good properties.  It is well known in the racing and high performance engine community. A great read on it, that won't hurt your head, is here.....

http://bobistheoilguy.com/moly-basics/

Think of moly like a deck of playing cards.  If you are pushing boxes along a ramp, there is friction that tries to work against you.  If you spread out a layer of playing cards along the ramp, and then push the boxes, they slide along the ramp easier as the playing cards slide over one another.  Moly has a natural plate-like structure than acts like those playing cards.  But it does not build up like has happened with some the late night TV oil additive stuff that gets advertised.  It is a natural friction reducer that can handle some very extreme pressures (over 500,000 PSI) and very high temperatures, and it will fill in microscopic imperfections in the metals it is used on.  It is well known and has been  relied upon in the lubrication industry, especially in extreme operating conditions like military turbine and aircraft rated reciprocating engines.   Some oil blenders though do not use it, as it is somewhat costly.  The higher quality oils and greases generally have some of it in varying amounts.    When you combine it with Boron in the form of boric acid, it provides a great tag team of friction reduction in an engine.  

What primarily shears in a motor oil is the viscosity improvers (VI) that make it work at being a 0w30 and 5w30.  It takes more VI to enable a oil to go from a low cold flow like 0w or 5w winter cold flow rating to a 30w at engine operating temperatures.  And there are different grades of VI that blenders use in their oils.  And this VI can shear under extreme pressure and cause the oil to go outside of the rated viscosity.  Some full synthetic 10w30 oils have the ability to flow at cold temps, yet use no VI at all to do so.  They are technically a straight 30w oil, but can naturally flow well enough in cold to qualify as a 10w30.  These base oils therefore typically have very low NOACK (burn off or vaporization rates), and are highly resistant to high temp high shear.  They are just plain tougher and hold up better in the worst of conditions.  

Given the timing chain issues that have become well known about the GM 3.6L DOHC engines and other issues, I prefer to use a 10w30 full synthetic that has generous levels of moly and boron, irregardless of GM wanting me to use a 5w30.  But I also prefer it in all of my engines from the little single cylinder in my Yamaha portable generator on up thru the 12.7L Detroit in my commercial truck.  I have found in the 12.7L, via stacks of used oil sample analysis reports, that a 10w30 seems to be more shear stable than even a 15w40.  I get lower wear metal numbers and better longevity out of the oil.  So oil thickness like 40w vs 30w is not the critical issue, it is the base oil makeup and the various additives that protect the engine.

 

 

 

 

Edited by Cowpie

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Thanks, great information !

I am familiar with Moly lubes etc. Seemed when I read your post it was something different to me, the name I guess MOS2, didn't click. As soon as you said Moly it all clicked.

There are a lot of owners, techs and dealerships out there that should read this. Unfortunately, most places that do oil changes buy the cheapest stuff they can to achieve a better bottom line.

As a line tech I liked it when people brought in their own oil, most of the time it was better than the "stuff" that came out of the bulk dispenser.

Once again, great job! Thanks for the info.... :hatsoff:


THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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Great info here, thanks.  Going to have to reread it a few times there is a lot of info to absorb.

Given that I am heavily involved with the 95 to 99 northstar I am especially interested in oil technology and developments.


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Another oil that wasn't mentioned here, that I used in my 07 Northstar with over 100k is the Euro spec 0W40. If I remember correctly it falls under the GM dexos guidelines too. Never had an issue with it either. 

Bottom line on oils is making sure the additive package is right for the engine and keeping the oil changed at the proper intervals helps more than anything. The latter especially. Good info here guys!

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Believe it or not, but I actually am using a Pennzoil conventional 10w30 in my LY7 3.6.  It meets the spec for the motor, which according to my owners manual is 6094M, also verified at Pennzoil website.  And the Petroleum Quality Institute folks did a test on the Pennz 10w30 conventional and it actually was better than many full synthetics in both base oil characteristics and additive package.  They were shocked at result and retested to confirm.  Same result.  It actually had better characteristics and stronger add pack than Mobil 1 Super Synthetic.  Boat load of calcium detergents in it and substantial amounts of the anti friction tag team of Moly and Boron.   Lower burn off rate (NOACK) than many 5w30 full synthetics, including the boutique brands.  A killer oil for only $3 a quart I get it for at my local Farm and Home store.  Some of us have speculated that SOPUS is using the new natural gas to liquid base oil in the formulation for it to have such good characteristics.

Edited by Cowpie

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