Can I run 0W30 all year?

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Jan 23, 2003
ON, Canada
During the fall I switched over to Pennzoil Long Life 0W30 blend HDEO. I just changed the oil on the car, and now I am on the second interval of Pennzoil Long Life 0W30. So far I am very pleased with it's cold weather performance.

Now my question is, would this oil be a good choice to run year round? It has a vicosity of 11.8 cSt @ 100C, which is considerbly thicker than the Pennzoil 10W30 dino (10.5 cSt)that I used to run in the summer. It also has a HTHS of 3.45 which is better than that of 10W30 dino (3.2). Plus, since this oil has 45-55% PAO, it should hold up considerbly better than a dino or other lesser blends. I don't really see any disadvantage to running this oil year round, and it will certainly simplify the logistics for my oil purchases.

The oil is going into my daily driver/run around car, a '85 Olds with a 307 Olds V8 (similar clearance specs to a small block Chevy). It gets a lot of city use, a mix of short and medium trips (although usually several throughout the day). The car usually gets one or two good highway trips per oil change interval. I should note that I am not willing to step up to a full synthetic with this car. I also intend to drive it until the wheels fall off.

I can get this blend at a very good price, which is part of the reason why I use it. Additionally, winters in this area can go below -35C, so I think the 0W30 is a necessity during the winter months. Summers here typically don't see hotter temps than 35C.

So any thoughts on the above? Does anyone have a better suggestion as to what oil to use during the summer months?

Pennzoil Long Life 0W30 spec sheet:

Pennzoil dino multigrade spec sheet:

[ February 09, 2004, 06:32 PM: Message edited by: Oldswagon ]
You can definitely use this! I wish we had this here. It's a nice 11.8cSt so you should be A3 rated or close enough to it. Amsoil's HT/HS for their S2k is 3.4 This one is 3.45 so it's very similar. TBN of 9.0 isn't too bad either.
I started using 0w30 in my Firebird the end of last summer and my first UOA had a lot of hot weather (30C+) driving on it and my results looked great.

That Pennzoil 0w30 looks like a very good oil, and can definitely handle summer driving with it's thicker 100c viscosity. How much do you pay for that oil?

I have used 0W30 M1 (that was BEFORE GC appeared guys...I haven't defected) year round including both very cold and very hot weather in demanding hilly high altitude driving in a Taurus Vulcan engine with nary a problem.
Thank you all for the advice. It looks like I should have no issues with running this oil year round. I am sure this stuff will protect the engine better than the regular Pennzoil dino that this car used previously.


The car hasn't used any oil during an OCI with any oil, or at least I haven't noticed an significant movement on the dipstick. The engine in this car is in excellent shape and is spotless inside.


I get 4 quarts of this oil for about $18 with taxes from a local parts store who is a Pennzoil dealer (this is lower than the list price). With a high percentage of PAO and a HDEO additive pack, I figure that this oil is a pretty good bargin.
Wait a sec....I thought that the lower the HTHS number, the better????? someone puh-lease school me here.
Add another who uses 0W30 year round. Amsoil in the Tahoe, Mobil 1 in the Sable (only because I haven't changed the Sable yet.) Used Mobil 1 prior to Amsoil S2K.

No problems.

Cheers, Doug

Originally posted by Schmoe:
Wait a sec....I thought that the lower the HTHS number, the better????? someone puh-lease school me here.

In the same viscosity, a higher HT/HS is generally better. This can be mis-leading in spec. sheets, however. Some oils start out high and deteriorate quickly. Higher quality oils will maintain. Generally, higher is better.
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