Yes I know everyone has had the oil type discussion before. I just want to know what would happen to the engine if I used 10w-30 fully synthetic oil? I love the extended performance oil from Mobil and they dont seem to produce a 05w-20 oil that is extended performance. They do make a 05w-20 fully synthetic which is recommended for a regular change interval. I guess I like the peace of mind for the extender performance one. Any thoughts or ideas?

Have you checked out BITOG? They're as nuts about oil as GH is about MPG

http://theoildrop.server101.com/ubb/ultimatebb.php

What brand?

Like lindermant said. Check "Bob Is The Oil Guy". They do a huge amount of independant testing and are absolutely fanatical about oil, filters and any automotive lubricant in general. Quite a few know their stuff. I lurk there quite often.

'00 Insight "Wazabi" -75,000+ miles
'03 Toyota Matrix - 81,000+ miles
'03 HCH-CVT-OSBM-41,000+ miles (retired 04-10-06)
"I'm very secure with my little Insight, no Prius envy here."

Hi Neoboy:

___Why would you even consider using 10W-30 anything in your HCH? If you cannot find 0W-20 (it will supposedly be re-launched in the spring of 06), use Mobil1 5W-20 Synthetic. 10W-30 will be like molasses in your cars veins. For the love of God and Country, don’t do it!

___Good Luck

___Wayne R. Gerdes

Ok, I meant to write a short post, but I wanted to avoid posting unsubstantiated opinions, so I did a little research. Now I can post other people's unsubstantiated opinions instead, sorry it kinda grew during that effort. :-)

I don't know if any of this is right, so I look forward to what others will say.

According to rumor on this site, the downside to a higher viscosity oil is that in today's very tight tolerance engines a higher viscosity oil will coat engine parts less well because it can't fit into the cracks as well. I went searching on the web and found little support for this contention. There were concessions that the HCH should use a lower viscosity oil since it was designed for it but no reasons were given.

Here is one article that includes the HCH concession (beware that it is marketing material, but every once in a while even a marketing department gets it right):

http://www.synlube.com/viscosit.htm

We generally assume that increased viscosity will reduce FE in our HCHs. In the article above they claim it is something like .1 mpg penalty going from 5w20 to 5w50 (which is what they are selling). I am betting that it is more in the HCH as it is highly sensitive to all things affecting FE so maybe a whole mpg at worst.

They claim that going from 10w30 to 5w20 will reduce average engine life from about 150k down to 130k or therabouts and quote a lot of auto manufacturers (including Honda) to support their claims so this one appears plausible at least on the surface.

They had a fallacious comparison between diesel engines and automobile gasoline engines which can be ignored, I don't think anyone gets a million miles out of an auto engine just by putting in a higher viscosity oil. But if their apples to apples numbers hold up you could postpone the need for an engine rebuild from about 130k up to around 180k miles by switching to a higher viscosity oil (read 10w40 for the HCH).

In particular, they claim that the cP (High temperature-shear - HTHS) number is a major factor in determining an oils protective ability and recommend getting as close to 5 as you can get.

On to what I found out about M1 Extended performance oils:

According M1's web site their extended performance (EP) M1 formulation has 36-37% more cleaning and anti-wear additives than the standard M1 formulation. This sounds great, but given my previous bias towards a low viscosity oil I would not have considered touching it. Based on the article above I may revisit this opinion.

Here are some Kinematic Viscosity data that have been previously posted here with the new M1 EP formulation added at the end, I have added the HTHS numbers where I could find them:

Mobil1 SAE 0W-20
cSt @ 40 degrees C = 43.0
cSt @ 100 degrees C = 8.4

Amsoil SAE 5w-20
cSt @ 40 degrees C = 45.4
cSt @ 100 degrees C = 8.5

Pennzoil SAE 0W-20
cSt @ 40 degrees C = 46.5
cSt @ 100 degrees C = 8.7

Mobil1 SAE 5W-20
cSt @ 40 degrees C = 48.3
cSt @ 100 degrees C = 8.8
cP @ 150 degrees C = 2.62

Mobil1 EP 5w30
cSt @ 40 degrees C = 57.3
cSt @ 100 degrees C = 10.25
cP @ 150 degrees C = 3.08

Mobil1 EP 10w30
cSt @ 40 degrees C = 66.57
cSt @ 100 degrees C = 10.5
cP @ 150 degrees C = 3.21

Mobil1 EP 10w40
cSt @ 40 degrees C = 91.07
cSt @ 100 degrees C = 14.2
cP @ 150 degrees C = 3.9

Mobil1 EP 15w50
cSt @ 40 degrees C = 133
cSt @ 100 degrees C = 18.2
cP @ 150 degrees C = 4.43

Note: Amsoil's marketing claims also boasted of increased anti-wear and detergent packages compared to standard M1, Mobil appears to have risen to the challenge with its EP formulation. :-)

Synlube recommends 0w40 for our HCH, since apparently when an engine is designed for 5w20 there is some change over 10w30 targetted engines. I couldn't find the specs on their 0w40 however.

Here is a table listing the minimum requirements for conformant multigrade oils.:

http://www.maintenanceworld.com/Arti...l_can_tab2.gif

Here is synlube's version of it (table at the end):
http://www.synlube.com/sae5w-20.htm

Both tables appear to match where HTHS is concerned.

After doing this research I am a bit startled and thinking about putting a higher viscosity oil into my car, although at $20/qt synlube is not practical, but M1 EP 10w40 is.

I will wait to see what others have to say. And if I try a higher viscosity oil I will post the mpg results. I am interested to know if anyone else has already tried it?

- Kurt

Hi Kmh3:

___And again, why would you use that heavy weight oil? Longevity? What longevity are you going to gain from stressing every moving part in the ICE lubricated by that fraction of a ft.-lb more over the life of the vehicle? Vehicles do not fail because of high quality lubrication choices so why would you choose an oil that will lower your FE by way more then .1 mpg AND will not do anything other then make your ICE work harder? You are being taken Hook, Line, and Sinker w/ the BS linked.

___Good Luck

___Wayne R. Gerdes

Ok, so why don't you say what you really mean excel. :-)

I looked some more and I stand corrected.

Here is a (non-marketing) article telling why NOT to use an oil of a higher viscosity than the manufacturer recommends. It affirms the common widsom of this group, that a higher viscosity is likely to damage engines designed for lower viscosity oils.

http://www.gatewaycleanair.com/mecha...7_2/story1.htm

(They are part of the Missouri Department of Natural Resources).

So the short answer is use what the manufacturer recommends, 0w20 (or 5w20 in a pinch) in the HCH case. Anything else is likely to damage your engine.

thanks,
- Kurt

Hi Kmh3:

___Thanks for that linked article and it was a nice find indeed

___Good Luck

___Wayne R. Gerdes

Thanks for all the feedback. I also had a chance to look through several sources and the weight they post is only a recommendation. If they wanted you to use a specific type of weight and or oil they would have to give it to you for free as per US law. (i.e. bmw)

My oil change will be done next week and I decided that i was going to use the 5w 20 from Mobil fully synthetic. The reason I asked about the weight is that I like Mobil
EP and they don't offer that weight(0w-20). I use that in my explorer which also calls for a 5w20 and never had any problems and if anything helped maintain sticker or higher MPG.

Living in Texas, I always worry about how well oil is maintained 100 degree weather + whatever is inside the engine. I have come to the belief that if it doesnt survive Texas heat it was not meant to be else where.

I also feel that from all the research I have done. It does not matter what you end up putting in as long as you change it when your suppose to do so and keep up other preventive items. I just happen to prefer Mobil ;-).