Oil? Castrol Syntec vs Mobile 1 & does brand matter in o

"charliebeagledog" wrote in message news:5bWdnXFby6vnF_jUnZ2dnUVZ snipped-for-privacy@giganews.com...

Now you've done it...you opened Pandora's box.

I suggest you read the owners manual and use what they recommend. (We have a 2007 Avalon and I use Castrol which meets the specs).

This car did not come with synthetic in it, and since I change my oil regularly and frequently (3000-5000 mile intervals) I see no need to change to full synthetic. When I change it, the old oil has darkened, but it is clear and "bright" (no solids or sludge).

There are differences of opinion as to what constitutes a true synthetic oil. To synthesize means you make something substantially different from its elementary starting materials. Mobil 1 uses rather specific starting materials and they end up with a molecule that is substantially different from those components. Some other manufacturers refine crude oil, hydrogenate it, distill it, etc and it is also substantially different from the starting materials.

Is one better than the other? That argument will never be solved on this group, as opinion reigns supreme, and accurate data never shows up.

Some kinds are not. I believe the 5W-40 grade sold in the US still is.

It doesn't really mean anything and it doesn't really matter all that much as long as it meets the same specifications. Mobil 1 is fine, but I don't think it's necessarily any better.

You should know that the synthetic oils will generally leak around seals more easily, so if you have a few engine leaks, you're apt to have more with the synthetic than with conventional oils.

If I were you, I would consider running a synthetic with very strong solvent characteristics like the Royal Purple stuff.... change it every

3,000 miles... drive for a while. Pull the valve covers and if they look clean inside, change to whatever oil you like, conventional or not.

That is, I think the most important thing right now is to get all the gunk out of the engine. But I'll also say that the LEAST of your worries is the sludge buildup... I would be more worried about having extreme wear from the infrequent oil changes.

--scott

I'd worry about both. The previous owner's neglect and the engine's alleged propensity for sludging are a bad combination.

(There was a big class-action settlement in this regard, the remedy for which was an 8-year unlimited-mileage warranty for engine related sludge damage, but I think it only covered certain engines from a span of several years ending in (lucky you) 2002. I don't see any oil sludging problems among the 11 Technical Service Bulletins on the '03 Avalon:

Supposedly a design change in June 2002 lessened or solved the problem: Frankly, the question I'd ask is "How well is the car performing?" (adequate power? acceptable oil consumption?) before doing anything radical. You might have dodged the bullet... or maybe nobody was shooting at you. For sure I'd be reluctant to shock the system with an aggressively cleaning oil. Instead, I'd do severe-service-interval oil changes with your favorite brand of conventional oil and a Toyota OEM or comparable quality of new filter every time and let any residual sludge come out gradually.

Best of luck,

--Joe