Tire advice and outcome

Thanks for those who posted tire advice concerning my 2000 Dakota. I went back to the stock size in an all season passenger car tire but not without some difficulty.
At Wallyworld, I told the service writer the size. I had a copy of the list and so did she, and she turned to the truck tire page.
"I don't want truck tires (taking the advice here). I want passenger car tires."
"I'm not looking at truck tires (the page was captioned 'light truck and SUV') I'm looking at.... .... .... tire tires."
"Well the ones I want are on the first page. (Pointing on my copy to some Uniroyal AS tires). Turn the white walls in."
So after sorting that out, I looked at the authorization ticket and it said 5W30 for the oil change (apparently computer generated based on the vehicle info) and I said I wanted 10W30.
After maybe half an hour, I got paged to the service department where the following conversation occured with the mechanic.
"Do you know the size you've asked for isn't the same as what's on the truck?"
"Yea, but the size I've picked is the right size. Its what's on the sticker, same size as the spare. The previous owner put on oversize tires. Don't know why."
"OK. Just thought I'd better check. It did look like it was sitting a bit high". (Now, how high its sits is a real good method of determining the right size tires, don't you think?)
So I went and wandered back out into the store. Then I got paged again. Had this coversation with the service writer and manager.
Service writer
"We only have three of those tires."
Manager interjecting while passing through
"The computer says we have four, but one is mislabeled as a 75 when its really a 70. A 70 is shorter."
Me
"What else do you have?"
The service writer flipped to the LT/SUV page, indentifed some gypo brand WL tire in a P size but with an LT tread pattern and checked inventory on the computer. Looking over her shoulder, I saw inventory of "1", so I didn't have to argue that point with her (fortunately, after the earlier discrepancy, it didn't occur to her that computer inventory might be wrong on this one too!).
So she went back to page one and suggested a Goodyear something or other (silence on my part, remembering the advice here) and then went to the inventory screen... which fortunately for me showed 3 in stock, so I figured I was safe.
Service writer
"Let me call another store and see if I can get you a 4th tire. If they have one we'll go get it right away."
So it turned out the other store had enough to make a set of 4 on both the Uniroyal and the Goodyear.
Service writer
"They have both. Which do you want?"
Me (seems real obvious)
"My first choice."
OK. That's done, so I wandered back out into the store again, for a long time this time, and, wondering if this was all manipulation to get me to buy something before they'd cut my truck loose, found an Old Blue Eyes CD to give as a Christmas gift to a relative old enough to remember when Old Blue Eyes was a new and upcoming singer, plus Jo Dee Messina's Greatest Hits for me. (Fervent hope I'd done what was needed to get my truck finished.)
Finally, I was paged that the truck was ready.
Service writer
"The sticker on the oil cap says 5W30. Y'know, its best to use what they say. I know someone who used 10W40 and it gummed up her engine and ruined it."
At this point, I wasn't particularly upset, although I was 3 hours into the deal. After all, they did sell me what I wanted (except for the oil) and they made a good effort to get the tires I wanted (and most fortunately, did so quckly within the context of the capabilities of doing so.)
So overall I'm happy. After all, had I gone to a real tire store, when they found out one of the 4 75s on the computer was actually a mislabeled 70, those "professionals" would have tried to sell me a whole set of 70s based on the pitch that a wider tire puts more rubber on the road. Blessed are the true amatuers!
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(snip)
Thicker oil protects the engine better, but the default suggestion is almost always 5W30 or even 0W30 (ZEROW30). This is because thinner oil offers slightly better fuel economy. So it MAKES SENSE for a car manufacturer to suggest lighter oil be used. Most people don't keep their cars (even if they bought it USED) long enough to wear out the engine. If lighter oil is used, the car manufacturer can claim that their cars get better fuel economy. But even the car manufacturers contradict themselves on recommended viscosity for oil. The oil cap on my car specifies 5W30. The only time 5W30 has ever been in the engine is (possibly) when the engine left the factory. But IN THE OFFICIAL SERVICE MANUAL for that SAME EXACT VEHICLE, 10W40 is recommended. In fact, it specifically states that all viscosity levels from (5W30) on up to (20W50) CAN be used. Yes, 20W50. Of course, it has a chart showing outside temperature relating to various viscosity levels of oil. Basically, the hotter the temperature, the thicker the oil should be used. But if you study the chart carefully, you will see that either 10W30 or 10W40 can be used safely year-round. This is on a car with "5W30" on the oil cap.
Unfortunately, the people working at quick change oil shops aren't the brightest bulbs on the tree. They see the computer recommend 5W30 or read it on the oil cap, and think that a customer must be NUTS to want to put thicker oil in their car to protect the engine better. There's no point in mentioning the Service Manual recommendations, either. The Oil Cap MUST know more than the people who wrote the Service Manual, right? :)
I'd be highly skeptical of the claim that simply changing from 5W30 to 10W40 caused an engine to get gummed up and ruined. I would expect that changing from 5W30 to 10W40 might (at worst) significantly lower that vehicle's fuel economy. -Dave
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wrote:

Hmmm... only the 4.7, of the 4 engines offered in the 2000 Dakota, carries a recommendation to use 5W30.

Mopar people do.

What?!?! They all have their training certificates displayed! <G>

Interestingly, I bought that oil cap as a replacement for the OEM cap as part of the "cure" for the 4.7 filler neck condensation/milk problem.

Are you sure you meant to say "highly skeptical"? That seems more than a bit reserved considering the whole situation.
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Pickups are gas hogs anyway, so thinning out the oil won't help much. :) You'd probably find the manufacturing tolerances aren't ideal for thin oil on the other three Dakota engines. I had a car that would use no oil at all between fill-ups if I put 10W40 in it, but would use a little more than a quart of 5W30 between oil changes. I'll bet that the brand new dakota engines are probably the same way . . . they actually need the thicker oil. Nothing wrong with that. -Dave
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wrote:

Or because the engine has some particularly small passages and clearances. In that case a thicker oil is probably not a good idea.

CAFE also forces the issue.
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On Tue, 06 Dec 2005 23:17:25 -0600, snipped-for-privacy@yahoo.com (Brent P) wrote:

The owner's manual says 5W30 is preferred for temps up to 100 degrees for the 4.7 because fuel economy will be better. It specifically says that fuel economy is the reason.
Guess they didn't need any fuel mileage help with the 2.5, 3.9, and 5.9, all which give 10W30 as preferred and 5W30 as acceptable. Wierd stuff. (Probably some double talk going on here.)
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On Fri, 09 Dec 2005 08:52:29 -0500, edward ohare

Not just probably, and not just a bit.
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I think there's a lot of fallicies about Oil floating out there, and what Oils should be used on particular vehicles.
Thicker oil won't necessarily protect any better, and in fact may do more damage than good. If thicker oil was better, hell throw 15w40 in there, even 20w50? Better yet, lets put 75w90 in there?
If you read up on Oil, you'll find essentially, that Multi-Weight oils become what they need to be according to weather, and engine temperature. That's the purpose, and design of Multi weight Oils versus the straight weight Oils of yesteryear.
A 5w30 Oil is 5 weight when an engine is cold upon start-up, then as the engine warms up in effect becomes a 30 weight Oil.
With a new vehicle that the manufacturer states 5w30, that's what you should be using, not 10w40, 20w50, or whatever. The only reason an engine that calls for 5w30, and is burning it, is most likely due to wear-high mileage, and then yes, perhaps a heavier weight Oil would be more suitable for a high Milage engine. (or an oil Additive)
On my Chevy SUV, I've used 5w30 since new, never deviated to any other weight, and my vehicle has never consumed oil that I'd have to add a drop between Oil changes.
Engines will last a long time, if you properly take care of them. Some people neglect to even check their Oil on a regular periodic basis, then find they're 2-1/2 qts low. This is what really tortures an engine.
A more correct accurate statement would be Synthetics will protect better than conventional oils, particularly in temp extremes. Another truth is that cheap 99 cent a qt Oil is recycled Oil. You basically get what you pay for. Mark
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On Thu, 8 Dec 2005 00:12:32 -0700, snipped-for-privacy@webtv.net (Mark D) wrote:

SNIPPED
Explain WHY synthetics protect better than conventional oils. Other than the FACT they do not thicken as much when cold, or thin as much when hot?
Another truth is that even some "expensive" conventional oils are produced from recycled oil, and that used engine oil is a VERY good feed stock for oil refining. It has less of a lot of the crap that has to be removed from crude oil to make a good lubricant. The secret is, it has to be RE REFINED oil.Not just filtered/scrubbed and doctored with additives.
Another truth is CAFE is dictating the oil recommended by manufacturers more than engineering. If an engine is designed so that a 10W40 oil can not flow through the oil galleries adequately to lubricate the engine and 5W30 can, someone should shoot the engineer - it is engineered too close to the failure limit.
Lighter oil provides less pumping resistance, and less shear resistance than heavy oil - which lets the engine put more horsepower to the flywheel for the same amount of fuel - this is the MAIN reason lightweight multigrades are recommended today. They can get away with these lighter oils because finish tollerances and metallurgy are much better today than they have been in years past There are fewer "high spots" and other irregularities in wear surfaces today, that REQUIRED a thicker oil to provide protection - so an engine will last as long or longer with light oil today in comparison to the engines of yesterday - regardless what oil you fed them.
When my engines get close to the 100,000km mark I move to a heavier oil - with a wider viscosity spread - and change it early enough that shear induced viscosity breakdown never becomes an issue (10W40 or 15W40 oil changed every 5000km or 3 months). Usually I BUY my cars with 100,000km on them, so I personally use VERY little 5W30.
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Explain WHY synthetics protect better than conventional oils. Other than the FACT they do not thicken as much when cold, or thin as much when hot? =====================================I did explain why in my post you responded to, and you have written it again here in your above statement.
The other reason, you state in one of your last sentences in your own post. Due to additional additives that are put in full Synthetics, they are more resistant to viscosity-molecular breakdown. mark
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