which brand syn.

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Aug 21, 2003
I have a 03 Silverado 5.3 with 10,000 miles. I am thinking of switching to synthetic but can't decide between Valvoline which is the only dino I've ever used, Mobil 1 or Penzoil. I know alot of people swear by Mobil 1 but is one any better than the other ? I mostly use truck for driving to work and back and in the winter to pull a 2 place sled trailer.


If you want a true synthetic, rule out Valvoline, Pennzoil and Castrol "synthetics" (except Castrol's imported 0W30 Syntec). These are specially refined oils, and not "bad," but they are not true synthetics (if you are going to pay the big bucks, get the REAL stuff). If you REALLY want to go synthetic you need to look primarily at Mobil 1, Amsoil, Redline, or Castrol German 0W30 Syntec. Which one? My recommendation would change depending on the weight you prefer and how long you want to go between changes. What are your typical winter/summer temps, how far is your drive to work and how often/how far do you pull the sled?
Summer temps usually 75-85 and winter usually 10-25 degrees. Sled usually only gets pulled 175 miles one way.
I think an oil should be measured by its performance and not the base oil's group number.
The "my oil is a true synthetic, and yours is not"
arguement is getting real old in a hurry.
Look at some of the UOA's on Vavoline. You will find it is not a preferred oil to a lot of members here. They are TIGHT with their additive packages. I would suggest Mobil. I just made the switch from running Pennz. purebase (dino) on a Accord V6, and I am digging it. Have noticed a little bit better acceleration. Hey, my wife said something to me about it after I changed the oil and didn't tell her I switched brands. That was a good sign.
There have been umpteen thousand UOA on Mobil and they hold up quit well. You could comfortably go 5K without any worries. I try the 10W-30 in the summer and then the 5W-30 in the winter. Walmart carries this oil on a regular basis.
I have the same truck! I switched to Mobil 1 at about 3,000 miles. I got a good UOA report for a new engine woth Mobil 1.

It is not a matter of "bragging rights"; it's a matter of getting what you pay for. If you like to pay more for an oil that, while it performs well, is not as expensive to produce as a full synthetic, and so you give the supplier a larger profit margin, I have no beef with you. That is your choice. But I am NOT going to tell someone who wants to use a REAL synthetic to use a Group III product without letting them know there is a difference, a difference significant enough that Mobil was willing to go to court over it.


Chris B has given you one of the most valuable inputs you'll get on this board...a good UOA from the SAME type of engine. Obviously, one UOA does not a superior oil make, nor, obviously, are your driving conditions identical with Chris B's, but I'd say unless you have a particular oil you are leaning toward, he's given you a good reason to try M1 (as has Schmoe).
Pennzoil, Valvoline, and Castrol synthetics are all good oil. It's not true that when you put anything other than Mobil 1 in your car it wears out the next day
Mobil 1 is great oil but that doesn't mean the others are bad
How big is the sump? How much do you want to spend? How often do you WANT to change it? Check out Penzoil HM 10w-30, $2 per. Rotella Synth will set you back $3, Mobil 1 $4. If you are changing twice a year in a big truck, I'd just get the Penzoil HM. Rotella if you want to go a year, Mobil 1 for about 6000 miles.
Mobil 1 gives you the most bang for the buck if you buy the 5-qt. jugs. For the quality you get, it's hard to beat.

German Syntec is a great oil if you like to drive vast distances and snoop around Autozones a lot.
That would be my second choice for your vehicle.

Redline if you simply must have the best at any price and are crazy enough to pay for it.
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