Which of these 4 Synthetics...

[tig1]

Originally Posted By: CaveatLector
Thanks for the replies everyone.

I am going to stay with Mobil 1 but I am switching to a better version - there is one version that I did not consider that has better cold AND hot performance than the standard 5w30 Mobil 1 I have always used, according to Mobil 1's chart - "Mobil 1 0W30 Advanced Fuel Economy". The Mobil 1 website oil selector for my vehicle listed (7) 5w30 options and (1) 0w30 option that they say I can use for my vehicle.

Seems 0w30 would have better flow at cold start up. Any penalty for going to 0w30 especially in hot summers in Texas? I am less attracted with the fuel economy benefit of 0w30 and more interested in the easier cold cranking and better oil flow when cold. I start the van often during the day and make a lot of short trips.

Any reason I should not switch from 5w30 to 0W-30?


Either one will be fine. I only encourage you to extend your OCI from 5K.

 

[GMBoy]

I may be old school, but if you are not worried about mileage why go 0w30? I think with the age and miles you should be at 5w30 or even Mobil 1 10w30...you mentioned Texas heat and I live in Texas as well and woould encourage you sticking to 5w30. Our cold starts in TX don't mandate a 0Wt oil and even with a lot of starts, the 5w30 is fine.

 

[batook]

Originally Posted By: GMBoy
...you mentioned Texas heat and I live in Texas as well and woould encourage you sticking to 5w30. Our cold starts in TX don't mandate a 0Wt oil and even with a lot of starts, the 5w30 is fine.

"The reason that multi-grade oils were developed in the first place was to address the problem of oil thickening after engine shutdown. Over the years we have been able to reduce the amount of thickening that occurs. Never-the-less there is no oil that does not thicken after you turn your engine off. This is why we have to warm up our engines before revving them up. Engine designers always pick the recommended oil based on a hot engine and hot oil. There is no issue with oil thinning as they are both matched when hot. The problem is oil thickening when the engine cools."

Even at 75F, an 0w30 weight is too thick at startup (40cS when it needs 10cS, which is the thickness of a 30 weight oil at 212F operating temp). A 10w30 oil has a thickness of 100cS at 75F. A 5w30 is somewhere between 40 and 100cS at startup in 75F heat. They all thin to 10cS at 212F operating temperature.

"Now you can see that the difference between the desired thickness your engine requires ( = 10cS ) is closest to the 0w30 oil at startup. It is still too thick for normal operation. But it does not have far to go before it warms up and thins to the correct viscosity. Remember that most engine wear occurs at startup when the oil is too thick to lubricate properly. It cannot flow and therefore cannot lubricate. Most of the thick oil at startup actually goes through the bypass valve back to the engine oil sump and not into your engine oil ways. This is especially true when you really step on that gas pedal. You really need more lubrication and you actually get less."

Originally Posted By: GMBoy
I think with the age and miles you should be at Mobil 1 5w30 or even Mobil 1 10w30

Your thinking is backards here. If you are proposing that the OP should use a thicker oil because the engine has high miles and is more worn, you would maybe suggest an 0W-40 or even an 0w50, but increasing the first number to a 5W or 10W would only cause increased wear at startup, without adding any additional protection or being any more thick at operating temps than the 0W. Also, we're talking synthetics here, so a larger spread between the numbers isn't as much of a concern as it would be with a conventional oil that would have to use more VIIs and polymers to achieve an 0w30 weight as compared to a 5w30 or 10w30.

"I used 0W-20 in my Ferrari 575 Maranello. It had over 5,000 miles on the clock. There will be a day (my estimate is 50,000 miles) when one will have to go to a 0W-30. In the future one will have to increase the viscosity to a 0W-40, then a 0w50, maybe. You should use whatever it takes to get 75 PSI at 6,000 RPM during the lifetime of the engine. This formula works in all situations."

FWIW, I run Mobil 1 Advanced Fuel Economy 0w30 in my two Toyota vans year-round (6-mo/5k OCI), both of which have over 100k+ more miles than the OP's Astro, and let me tell you, they LOVE this stuff. I used to run 5w30 but switching over did increase fuel economy by 1-2 MPG, and the engines run quieter with less valve tappet noise. I suggest you give it a shot.

(The above italicized quotes are by AE Haas, author of the "Motor Oil University" articles on BITOG here): Do Your Homework

 

[JCM35]

Synpower. Really minus the highmileage oils the others will do the same thing. No homework needed.

 

[DutchBrad]

I run 5W20 in my '96 Astro. I short trip quite a bit, run it 3-4k. Currently have Valvoline conventional in, but switching to peak 5w30 conventional (got on sale) next, but then will move to Pennzoil Conventional 5w20. I have a rear main seal leak, thought the thinner oil would make the leak worse, but that has not been the case.

 

[CaveatLector]

At next oil change I am going with Mobil 1 0W30 Advanced Fuel Economy. Unless someone can convince me to go with 0W20...

For full synthetic oils, is there any benefit to using 5W30 or 10W30 instead of 0W30? Why don't we all just drop 5W30/10W30 and go to 0W30?

 

[Radman]

batook has given a very good post. If you want a Mobil syn for a worn Chevy engine in a hot climate drop the 30's and go with 0W40.

 

[JavierG]

Originally Posted By: CaveatLector
Thanks for the replies everyone.

I am going to stay with Mobil 1 but I am switching to a better version - there is one version that I did not consider that has better cold AND hot performance than the standard 5w30 Mobil 1 I have always used, according to Mobil 1's chart - "Mobil 1 0W30 Advanced Fuel Economy". The Mobil 1 website oil selector for my vehicle listed (7) 5w30 options and (1) 0w30 option that they say I can use for my vehicle.

Seems 0w30 would have better flow at cold start up. Any penalty for going to 0w30 especially in hot summers in Texas? I am less attracted with the fuel economy benefit of 0w30 and more interested in the easier cold cranking and better oil flow when cold. I start the van often during the day and make a lot of short trips.

Any reason I should not switch from 5w30 to 0W-30?

Ok, why do you want to switch again? What are you not getting from your current choice of oil? How cold does it get in Texas? And why only Mobil or Valvoline? I came to the party late.

 

[67Customs]

I say go with Mobil 1 0w30 at 10K OCI.

 

[semaj281]

Originally Posted By: cchase
These engines are easy on oil. If Mobil 1 5w30 has gotten you this far I see no reason to change even with a 10k OCI. If you're short tripping it I'm not sure I'd run any oil to 10k.

I'm also going to say if it ain't broke..