About oil

What is the chemical difference among the following oil types compared to the standard:

High Mileage
SUV, Truck, Vans
Clean 7500 (Mobil)
Clean 5000
Extended Service
Syntec Blend by Castrol
Platinum by Pennzoil

Also, the various viscosities ranging from 0W-40 to 15W-50. I know that the lower figure with "W" stands for cold or winter but is the significance of the upper digts? .What exactly happens to oil from a cold start to warm up? Are oil additives cost-effective? Do they really increase mileage and performance as advertised. I work part time for a major auto parts store and I astonished at the variety of oil and how people get suckered into buying the well adverised ones without really feeling the difference. Maybe I'm odd out but I stick to changing oil every 3-4K miles using the standard 5W-30 oil. Would surely like to hear your opinion.

Hello DonSor,
You can't go wrong with using regular oil and changing it every 3-4K. The only exception that I've done, is to switch to Mobil one with my 98 Volvo S90 (at the insistence of the Volvo group I belong to). We'll see how that helps.

The upper number is the viscosity of the oil at operating temperatures. Beyond, that I'll need to let other more knowledge people answer your questions.

Best Regards,
Stan



What is the chemical difference among the following oil types compared to the standard:

High Mileage
SUV, Truck, Vans
Clean 7500 (Mobil)
Clean 5000
Extended Service
Syntec Blend by Castrol
Platinum by Pennzoil

Also, the various viscosities ranging from 0W-40 to 15W-50. I know that the lower figure with "W" stands for cold or winter but is the significance of the upper digts? .What exactly happens to oil from a cold start to warm up? Are oil additives cost-effective? Do they really increase mileage and performance as advertised. I work part time for a major auto parts store and I astonished at the variety of oil and how people get suckered into buying the well adverised ones without really feeling the difference. Maybe I'm odd out but I stick to changing oil every 3-4K miles using the standard 5W-30 oil. Would surely like to hear your opinion.

I checked out API.com (American Petroleum Industry) and most of the "expert" comments I've read by contributors were that "we're getting ripped off". Unless your dirving a high performance car long distances during high ambient temperature, you don't need synthetic. Our greatest challenge is to minimize wear during stop and go drives at short distances. The greatest period of wear on the engines is during cold start without proper warm up, meaning that one starts the car and scoots to 60 MPH on the freeway right away. The recommendation was to get started and remain at around 20MPH for the next fifteen seconds. Nonetheless, I will stick with my practice. Thanks for the input.