So last oil change my monte was at 76,000 miles and I decided to switch from mobil one full syn (which has been used since the car was new) to a Valvoline high mileage blend. Its almost time for another change and now I'm wondering if mobil one would be better to use even after the engine hits 100,000 and over just because it doens't break down?

One other question. Is it true switching oil brands/blends is bad for the engine or is that just an old story?

 

[align=center]Hi Yellow Monte,[/align][align=center]I hope the below information gives you some [/align][align=center]insight on what to do ?[/align][align=center][/align][align=center]Afew links belong[/align][align=center]Read & Decide[/align][align=center]Good Luck, `Space[/align][align=center][:-][/align][align=center][*]Oil Change Every 3,000 Miles?[/align][*][align=center][:-] [/align][*][align=center]Synthetic Motor Oil: Should You Use It?[/align][*][align=center][:-] [/align][*][align=center]How to Buy Motor Oil[/align][align=center][/align][align=center]
Synthetic Motor Oil
By BY TOM TORBJORNSEN

Learn About Cars[/align][align=center][/align][align=center][/align][align=center][/align][align=center][/align][align=center][/align][align=center][/align]
[ul][*][align=center]Should I use synthetic oil? [/align][*][align=center]Does it work better in some cars than others? [/align][*][align=center]Does it cost more? [/align][*][align=center]Do I have to change the oil more frequently? Less frequently? [/align][*][align=center]Does it make my engine last longer?[/align][/ul][center][:-]
[font="times new roman"][size=4]First of all, let's take a brief look at the history of synthetic motor oil and its introduction to the marketplace.

AMSOIL INC developed the first synthetic motor oil to meet API service requirements. Lieutenant Colonel Albert J. Amatuzio, President and CEO of AMSOIL INC witnessed synthetic lubricants in action as a jet fighter squadron commander. Synthetic oils were developed for (and still are used exclusively in) aircraft jet engines because of their extraordinary capacity to reduce friction and wear on engine parts. Synthetic oil has an incredible ab

 

Why would you switch from a top grade oil to a conventional oil. ESPECIALLY after that many miles? It's your decision, but of the 5 vehicles I maintain (minimum) Mobil 1 or Mobil 1 Extended Performance is in EVERY vehicle. We have 600,000 miles on synthetic oil now, either Valvoline, Royal Purple, and now Mobil 1. As far as I'm concerned the ONLY reason to NOT use top tier synthetic oil would be if you're driving a leaker like a F__d pickup, where you fill the oil and check the gas.
My wife LadyT's '99 Silverado Sportside Z71 has OVER 182,000 miles, and ALL of them has been on Mobil 1, and now Mobil 1 EP. My Intimidator SS has 72,000 ALL on Mobil 1, my '01 SS LE had 116,000 when sold, ALL on Mobil 1, my '95 S10 Blazer had 166,000 when sold, and ALL on synthetics, Dad's '97 Lesabre has over 120,000 and the last 60,000 on Mobil 1, LadyT's '82 Olds Regency, and now LadyT's new Solstice GXP. NEVER has ANY of these vehicles even had a valve cover removed, nor ANY other engine problems. The Z71's engine looks like new inside the filler cap, as did the '95 blazer, as does ANY of them.
The non-boosted motors we run the Mobil 1 Extended Performance oil, change the filter and rotate the tires every 6,000 miles, and change the oil every 12,000 miles (15,000 mile oil). The boosted cars use regular Mobil 1 as recommeded by the manufacturer, and I change the oil every 5-6,000 miles. GOOD filters are a MUST! Wix is the best. Stay away from Fram, as they cheapened them for Wally World.

 

Okay that settles it. I'm going to change it back to Mobil 1 full syn as soon as i can.

 

Good call. The only reason to switch to regular oil is if the car starts burning oil. It means there is some wear somewhere in the engine and the synthetic oil is getting into it.

You can switch to regular and because it is thicker it won't burn but still do it's job.