Can I do this without harm

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Jul 31, 2003
I live in Ohio, In the spring, summer, and fall I can get by with 10-30 Penzoil. In the winter it can get down to 20-30 below, so I want to run Mobil 1 -- 5-30 sythn. oil for less wear and tear on the engine and fast engine lube. So is there any harm in this dino - synth. rotation, or would it be ok. The vehicles are Jeeps with a 4.0 engine, and all the engines are 15,000 miles or less at this time, except for one that has 77,000 miles. Thanks in advance.

[ August 07, 2003, 02:20 PM: Message edited by: badnews ]
I am doing the same here in MN. But i want to stay with the same brand. I will use Mobil dino 10w-30 now, and in winter i will use Mobil 1 5w-30 if it gets real cold, otherwise dino 5w-30 for winter. Why don't you use Pennzoil 5w-30 synthetic in winter, if you like to use the 10w-30 for summer?

IF Pennzoil made a Group IV/V synthetic I'd say the ideal situation would be a PZ Syn/PZ dino rotation; but they don't SO, I think your plan would work fine as you described it. I would consider doing an AutoRx treatment first and then putting 2 oz of AutoRx in your dino when you are running it. If you wonder why I don't recommend you use the PZ Group III "synthetic"...if you are going to pay for synthetic, get the REAL stuff.
Yes , if you are going to shell out the bucks for the synth. might as well get the best I thought, and as I have learned here Pennzoil synth. is not a true synth. never knew that till I came here. So it will not hurt a thing. Any others have any input. I am talking a fleet of vehicles here , some big bucks involved.
I do/have done this summer-winter change in several vehicles with no detriment.

I've used both walmart 5w30 synth and M1 5w30 and would have to give a slight cold cranking edge to Mobil One.

I use sale priced 10w30 dino of various brands in the summer.
Hey badnews,

Tell me if I've got this wrong:
You're running 10W-30 conventional ("dino") Penzoil for three seasons out of the year in all your vehicles, & you want something thinner for winter only.

Well, my first question is, "Why not Penzoil dino 5W-30?" I mean, isn't that what it's for? You'll get better cold-starting & cost savings.

My next question is, "How long between change intervals?" If your only running it for the winter, why is Penzoil's Grp3 syn undesireable? You're certainly not planning to run it for 20k miles between changes, right? Any decent Grp3 syn should easily go 5k miles in a non-turbo engine.

Now, if you were looking to save time & money (with extended drains) while getting better protection at the same time, & wanted an OTC Grp4 oil to do that, then maybe I could see spending the extra for Mobil 1 all year long. But not just for winter when you're running dino the rest of the year.
I would wse M1 all year you cannot get a much better oil .Additive clash and switching oils will not make any difference if that is what you decide to do. What makes Penz. group 3 oil bad is that around here it is the same price as a REAL synthetic oil.

[ August 07, 2003, 04:17 PM: Message edited by: Steve S ]
I live in columbus ohio, and up until a few years ago, I used 5w30 conventional oil in my daily drivers with no problems whatsoever. But then again, it hardly ever goes below 0 degrees here.

Well, my first question is, "Why not Penzoil dino 5W-30?" I mean, isn't that what it's for? You'll get better cold-starting & cost savings.

Well to answer, I thought the syn. oil flowed faster and easier under severe cold weather starting conditions and meant less engine wear, and dino oil was thicker under the same conditions meaning more engine wear, or have I misunderstood things ?? edit : Up on the lake things are a little bit more harsh.

[ August 07, 2003, 08:02 PM: Message edited by: badnews ]
Hey badnews,

Yes, you understand correctly: syn should flow better under extreme conditions. What have you been running in the winter?

One of the things you mentioned was cost. Is there any $ savings if you use Penzoil syn instead of Mobil 1?

I guess I'm thinking two different things here:
1) If extreme cold protection is primary, I'd skip the 5W-xx & go with a 0W-xx oil.
2) To keep costs down, I'd go with something else.
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