B.C.

Greetings all.

The previous thread about what type of oil to use (where I had also jumped to ask about oil weight) seemed to have wandered off track so I started this new, fresh thread since it really addresses another question anyway.

I contacted Mobil (makers of Mobil Clean Oil and Mobil 1 tri synthetic) regarding if there is a difference in using 5w-30 or 10w-30 during summer months. I had thought that there would be little difference in viscosity, etc. for typical temperatures encountered during the summer and that the real differences between these oils would show up only in cooler temperatures ie winter. Apparently, I was wrong and here is the response from Mobil verbatim...



Thank you for your inquiry.

Most car manufacturers recommend 5W-30 or 10W-30 grades for normal driving conditions. Improved engine technology with tighter piston ring and cylinder wall tolerances allows the use of a lower-viscosity oil without increasing oil consumption. (A “loose” engine – or one with wide tolerances - allows too much oil to get past the piston rings and into the combustion chamber, where the oil is burned along with gasoline.) We recommend that you follow the engine manufacturer’s recommendations as indicated in your owner’s manual. For maximum low-temperature performance and maximum fuel economy, use the lightest recommended oil viscosity. Heavier oils can impede engine starting,lower fuel economy and steal horse-power.


--
The above information is provided in good faith based upon the information presented by the customer. ExxonMobil is not responsible for any loss or damage resulting from inaccuracies or errors in any of theinformation provided or any acts or omissions taken in response to our
advise.



The last two sentences tell me that indeed there must be some viscosity difference upon cold startup as well as at engine operating temperatures even during summer months. The 5w-30 oil must have a lower viscosity even at full operating temperatures in order to allow for the better fuel economy they mention. After reading this, I will use 5w-30 year round. How about the rest of you?

maximizer

Now that you mentioned it. I remember during winter months once in a while when it got really cold (but never below 10F) I had problems with starting the engine. No it wasn't the battery. The engine would start and after 3-5 seconds stall, it seemed it was hard for it to start. (heavy thick oil). After second time or third it would start and run smooth. I'm running with 10w30 and it only happens during winter month. It never happened when it got warm. I never tested it with 5w30, I guess I'll have to wait until next winter and try it.

Another thing.. my idle is really low.. around 450-500 could this be because 10w30 is thicker and doesn't allow the engine to run more freely? I know 10 only indicates viscosity when cold ... but it makes me think.. I gotta try 5w30.

guido_sst

Going from 5W-30 to 10W-30 isn't going to have much if any effect on your idle speed. If you're idling at 500RPM, I would suggest making some adjustments.

chris j vurnis

I just tried some Mobil-1 0W-30 oil. Never used that grade before --

I think under the severe conditions I drive my car, the oil breaks down fairly quickly --- so I change it quite often but usually I've used petroleum based oil rather than synthetic.

Everytime my engine gets a mid-range knocking/pinging problem, I go out for an oil change -- most always fixes the problem within a few miles of driving.

I have 75K miles -- 95% city driving -- at least half of it was "stop and go".

dwapenyi

iTrader: (3)

Is your comparison between regular oils, or synthetic?? Your observations seem to match up quite well with comparing regular 5W30 to regular 10W30.

Now, if you compare synthetics, its a different ballgame altogether. I use 10W30 semi-synthetic all year round. It apparently has better flo characteristics than regular 5W30. Of course, 5W30 synthetic is the most slippery of all.

I mention this because usually when people are talking about Mobil oil, its normally Mobil 1 they're talking about, not Mobil 0.

DW

bill99gxe

iTrader: (1)

DW,

Is there a website that I can check out that investigates the specific flow differences between 5W-30 and 10W-30. (i.e. I would like to know where you saw this)

In using reason, Nissan recommends 5W-30. For extreme cases, especially in areas with harsh winters or desert conditions, 0W-30 and 10W-30 are also recommended. For what looks to be strictly environmental/"Save the Earth"/fuel economy reasons, 20 weight viscosity oils are now being recommended as well. Unless your smoking, losing oil or have a "special" motor, consideration of other viscosity oils is not necessary.

There is really not a need be so concerned about viscosity, especially when using synthetics. Actual oil brand selection, oil filter, and interval use are more important.

dwapenyi

iTrader: (3)

Look here at the Mobil1 site comparing 5W30 Synthetic to 10W30 Synthetic. When you look at cold weather properties, like pour point and others, look how 10W30 is very close to 5W30. Why I like 10W30 is because its good enough for the cold, better than 5W30 regular oil, and its thicker properties (the 30 part of the 10W30) are a bit better than 5W30 synthetic. Of course, this is pure synthetic only;

http://dallnd6.dal.mobil.com/GIS/Mob...7?OpenDocument

DW

bill99gxe

iTrader: (1)

DW = does research.

I think I'm gonna burst into tears.

Thanks! Some good reading there.

I used to use 10W-30, but since I typically go at least 10k per oil interval I would always have it in during the winter months and would notice quite a racket when starting up the car on a cold morning compared to 5W-30....

dwapenyi

iTrader: (3)

Thx

There was this other document I downloaded that I was trying to retrive. I probably have it on my home computer. It had a huge list showing all the properties o today's major brands. Everything from Pennzoil to Castrol, to Quaker State to to Amsoil. It was a it dated ,but still gave you a very good idea of the comparative capabilities od today's oils. If I find it, i'll post it up here.

DW

bill99gxe

iTrader: (1)

Please do. I'll throw that in my oil spreadsheet "sticky" post!

dwapenyi

iTrader: (3)

Here's an article from Consumer reports, dated from 1996. This is not the one I mentioned earlier. I still have to find that one. I think you'll enjoy this read

http://www.xs11.com/stories/croil96.shtml

DW

Jeff92se

iTrader: (82)

Oh my god, not the consumer reports link! That test was not run very well. Non-conclusive and directly contradicts alot of other testing. I just don't think consumer reports is equipped well enough to come to any reliable conclusions regarding oil. Saying regular dino oil that is changed regularly is fine is one thing. Saying dino = synthetics is quite another. See Bill's sig and quote.

sinewave

This may be the article you're referring to. It has ash content, flash point, etc.
http://www.bmcno.org/techtip_motor_oil.htm

dwapenyi

iTrader: (3)

Yeah, well, wen I read consumer reports, I don't take their opinions as verbatim, but use it as a , how can I say, interesting source for information. I remember sometime back when they tested the 87 Mustang GT, calling the engine inside too powerful for normal use and shouldn't be used on the street. I was in tears of laughter when I read that one!!

DW

dwapenyi

iTrader: (3)

Yeah, that's it! Thx

DW