10W-30 Synthetic HTHS Questions

[FrankN4]

Several people that I consider to be reasonable and also informed have tried to convince me to switch my 2008 Silverado from 15W-50 to 10W-30. I have never used anything other than 40 or 50 grade oils since my first new car, a 1964 Buick V6. I have never had any kind of engine problem, never, with 40 and 50. People are telling me that my 45 year streak is about to run out if I continue the high viscosity oil in my 08 truck. I don't know but I do have reasonable doubt.

What I have learned over the past few months suggests to me that HTHS is very important to engine protection as is cSt viscosity, within reason. The oil I have used the past 19 years has a HTHS of 4.5. and a 100C cSt of 18.1. ACEA A3 is a HTHS of 3.5, or better. European cars usually call for an ACEA A3 oil. A lot of high mileage oils have a HTHS of 3.5 or better. From this, I have attached magic, and a little logic, to 3.5 HTHS.

I started looking for 10W-30, SM, with a HTHS of 3.5 or better, and a 100C cSt of 11 or better. I could only find one and that is Valvoline MaxLife full synthetic 10W-30. I found several 10W-30 SM in the 10.0 to 10.7 100C cSt and HTHS of 3.2.

I can blend M1 15w-50 and M1 10W-30 and come up with a 100C cSt of 12.4 and a HTHS of 3.54. Mobil 1 said it was fine to do that, no problems. I can blend Amsoil XL 10W-30 and 10W-40 and come up with a 100C cSt of 12 and a HTHS of 3.5. Valvoline said their Synpower 20W-50 had a different chemistry from their other Synpower and they discouraged blending it with other viscosity Synpower.

I think I am trying to ask, or discover, if a HTHS of 3.5 will really protect, I mean really protect with a 100C cSt of only 11-12.

It was 10F this morning and I might see 10-12 days this cold all winter. 90+ is very normal for the summer. Me, my wife, all fluids, full camper pack puts me about 800 pounds under gross. The truck will see about 8-10 days loaded with full camper pack but it will cross the Smokey Mts all 8-10 days. I am looking for, expecting a service life of 200,000+ miles. Do you honestly believe I can do this with a HTHS of only 3.5 and a 100C cSt of only around 12? Feel free to laugh, feel sorry for, question my mentality, but this is vry serious for me.

 

[BuickGN]

While I don't think the heavy stuff is necessary, it's retarded for people to say it's going to hurt your new truck. Take opinions with a grain of salt. You've run something forever that has never let you down. With the exception of a few, most people post opinions with little mechanical knowlege. They just repeat things they read on here.

My Amsoil 30/10-30 has an HTHS of 3.5, I believe, but it's not published on their site. I'm sure Pablo can clarify.

 

[yeti]

15w-50 is waaaay too thick for an '08 engine. what is it spec'd for ? (5w-30 ???) if you MUST have a thicker than spec'd oil, think about GC. it has a HTHS of 3.5 or 3.6, and the 100C cSt is around 12.2, a "thick" 30w. why mix when you have an excellent choice like GC ? as well, you might want to think about potential warranty problems with a dealer if something should happen to the motor, and you have a molasses-like 15w-50 oil in the crankcase.food for thought, and happy new year.

 

[HTSS_TR]

Use the grade recommended for you 2008 Silverado during warranty period. After warranty expired, you may want to use a little thinner during winter and a little thicker in summer time, assume that you change your oil twice a year.

 

[yeti]

buickGN mentioned amsoil 10w-30. another excellent choice.

 

[BuickGN]

Originally Posted By: yeti
15w-50 is waaaay too thick for an '08 engine. what is it spec'd for ? (5w-30 ???) if you MUST have a thicker than spec'd oil, think about GC. it has a HTHS of 3.5 or 3.6, and the 100C cSt is around 12.2, a "thick" 30w. why mix when you have an excellent choice like GC ? as well, you might want to think about potential warranty problems with a dealer if something should happen to the motor, and you have a molasses-like 15w-50 oil in the crankcase.food for thought, and happy new year.


Why do you think 15-50 is way too thick for an '08? Again, show me where clearances have changed in the last 50 years. It's not completely necessary but if you're like me and expecting half a million miles, the extra HTHS might make the difference.

It's no worse than running a 5-30 in a Canadian climate.

And to clarify, I'm sure the truck would live a long and happy life on 5-30.

 

[aquariuscsm]

IMO,M1 15W50 is a somewhat thin oil. Shake a bottle of m1 15W50 silver cap,then a dino or synth 20W50.........pretty big difference.

I agree with BuickGN

 

[BuickGN]

Originally Posted By: yeti
buickGN mentioned amsoil 10w-30. another excellent choice.


I let a co-worker take the TL to get breakfast the other day. He comes back and starts saying how slow it is and how it only hit 90mph before the first redlight when his trans-am will hit 100mph. I thought he was joking at first and then realized he basically fired it up and floored it out of the parking lot.

The first thing I yelled at him was that it has a straight 30 weight oil and he ran it up to 7,000rpms dead cold. That was one time I wish it had a 0w-10 in it.

 

[aquariuscsm]

To FrankN4,I think M1`s silver cap 15W50 makes an excellent one size fits all year round oil. I used it for a long time,as well as several people I know.

 

[bruce381]

do not waste your time "blending" just get whatever is on sale in the vis grade you want. maybe go 1 grade lighter to put your mind at ease.

IMHO I like heavy grade do not like 20 anything.

try a oil change to a 10/30 and relax.

 

[sprintman]

15W50 very thin. 40W70 is real oil!

 

[HondaMan]

Frank4N,

I too have a new 08 Silverado (5.3L Non-Flex Iron Block)

I have thought about the same over and over.

I agree with many of the others on these points:

1. Forget the notion of 'blending' your own brew
2. GC is a nice choice as a 'thick' 30 ... does not meet warranty btw, but neither does the route you are going.


My choice? I have a case of Redline 5w-30 on the way. HTHS = 3.8
UOAs to follow in the comming months.

 

[vxcalais]

Mobil oils always tend to be on the thinner side of things within the listed viscosity ranges. When you compare them on par with say what Penrite make, you will see how thin Mobil really is. Some of Shell's stuff seems thinner as well. 15W50 is fantastic viscosity, maybe even try a 5W or 10W50.

 

[BuickGN]

Originally Posted By: HondaMan
Frank4N,

I too have a new 08 Silverado (5.3L Non-Flex Iron Block)

I have thought about the same over and over.

I agree with many of the others on these points:

1. Forget the notion of 'blending' your own brew
2. GC is a nice choice as a 'thick' 30 ... does not meet warranty btw, but neither does the route you are going.


My choice? I have a case of Redline 5w-30 on the way. HTHS = 3.8
UOAs to follow in the comming months.


That sounds like a good choice too. Maybe even Redline 10-30.

 

[Doug Hillary]

Hi,
FrankN4 - Obviously you should firstly consider what the manufacturer recommends. Consider Warranty requirements!

Shell's Rimula range of HDEOs includes a number of mixed fleet 10W-30 viscosity lubricants. Many have manufacturer Approvals that indicate a robust HTHS vis of around 3.5-3.7cP and a 100C viscosity of 11.9cSt or above

You could also consider both of Mobil 1 TDT versions, Delvac 1 5W-40 or the Shell equivalent

 

[yeti]

15w-50 is thick, relative to the 5w-20 or 5w-30 that most '08 vehicles sold in north america call for in their manuals. a thick oil would not cause any issues in his truck, and i even recommended that he look at a "thick" 30w, in GC. i use what my vehicles are spec'd for, (10w-30), and when my 3.9L dakota was out of warranty, i've used GC. if i had a newer vehicle that called for a 5w-20, i would use a "thick" 5w-20, and post warranty -- who knows?
aqua... -- agreed -- 15w-50 IS "somewhat" thin, relative to 20w-50. just as a 75w-90 would be "somewhat" thin relative to a 75w-120. the key word here is relative.
buick -- i hope that you yelled loudly at your co-worker for disrespecting you and your car. take care, guys, and happy new year. got to go -- i'm late for the rose bowl start, and 'sc just scored.

 

[FZ1]

Waaaaay too thick!!!!!If you think M1 10-30 is too thin; then try M1 EP,PP,or any "thicker" synthetics in that grade.

 

[BuickGN]

Originally Posted By: FZ1
Waaaaay too thick!!!!!


Based on what?

Here's an open question to anyone, who has ever seen an engine failure from too thick of oil?

 

[Jett Rink]

My favorite 40 weights are:
Shell Rotella 5w-40 and Mobil 1 0w-40.
I'm not saying they are necessary for your specific vehicle and application, but if you want a higher HTHS than your garden variety 5w-30, then those would also fit the bill.

Mobil 1 0w-40 will shear down to a 30 (which bothers alot of people), but seems to maintain a healthy HTHS in many applications. There are posts, I think in the foreign/import oils section where Audi and VW fellas go into alot of detail about Mobil 1 0w-40. I've used it in my BMW and my wife's Volvo turbo, with no complaints.

 

[FZ1]

Based on the oem spec. Ain't you learned nuthin'?