Full Synthetic Oil

[IPcamper]

As the engine runs, NO2 form from the combustion, this reacts with water to form Nitric Acid. This will build up in the oil over time and pit the metal and increase sludge formation. All of the oils have additives to neutralize this, but can only handle so much. Cheaper to change the oil and filter than to rebuild the engine.

If folks are told to change their oil once a year, and use cheap oil, or if they drive 20K + miles between changes, they are are going to sludge their engine up!
Based on the 4 engines I have rebuilt in the last 35 years, I will stay with the Mobil 1 and change it every 8k miles.

 

[Drewmcg]

I will stay with the Mobil 1 for my vehicles. I have a 2003 Explorer XLT with the V8. I purchased it new and have done every oil change with Mobil 1 at 8,000 miles, and used a Motorcraft oil filter. Last fall, at 206,000 miles, the engine started sounding like there was some timing chain issues. So I replaced the timing components on the engine. The inside of the timing cover was very clean for that 13 years and 206K miles. I am going to stick with the synthetic oil.

View attachment 150584

That cover does look pretty clean. If I were you I'd be tempted to use the Mobil 1 extended performance oil ("guaranteed" up to 15k intervals and not much more $$ than reg. Mobil 1) + the WIX 51372XP high capacity filter ($6.45 @ RockAuto + shipping), and push the interval to 10k miles. Motorcraft is a good filter but not rated high capacity/extended performance.

For my 120k motor with new timing cassettes, I'm sticking with Motorcraft filters since they are quality + cheap (bought a bunch at once to save shipping), plus either Costco Chevron conventional 5w-30 @ 5k miles interval, or "cheap" full synthetic (Menards sells Pennzoil Ulra under $7/quart, and Pennzoil has a $2 rebate that brings it down to under $5/quart), and maybe push the interval to 7k with the Motorcraft filter.

But the regular Mobil 1 and Pennzoil Ultra synthetics are not rated extended performance. Sure, they work fine for 7,500 miles in my Volvo (recommended oil change level), but does that necessarily mean they are rated to do that same in the Ford 4.0 SOHC (recommended 5,000 miles interval)? Different engine; different rating. And those timing chains in the 4.0!

So if want extended change interval, probably better to buy 5 quart jug of Mobil 1 5w-30 extended performance for less than $27 delivered ($5.40/quart) on Amazon now), and run it 10-12k miles with an Motorcraft oil filter change half way through at 5-6k miles. (The Motorcraft filters are roughly half the price of the Wix XP's. And the Wix XPs aren't nec. rated to 12k miles--or any specified miles.)

 

[Mbrooks420]

My motor had well over 150k when I was doing yearly changes. At 20k nothing came back in the red. That might be pushing it, but I'm sure at 5,000 it'd still be totally in spec.

 

[Centaurus5.0]

 

[MrPulldown]

So when does the "change oil" warning light come on. I just reset mine and kept on driving .

In addition when I do get around to changing my oil I am just going to mix all the remaining oil I have sitting in various 5 quart jugs. I think I have some Mobile 1 0-20. Mobile 1 5-30. Penzoil conventional 10-30. I'll buy and fill the remainder with some 5-20 that I will purchase. I'll keep the 10-40 and 10-50 out of the mix.