Conventional vs Synthetic Oil Debate

[Aidan Kesler]

Always ran a synthetic blend high mileage valvoline or conventional shell rotella, but heard yelling from both sides of the fence. Conventional is best or synthetic is best, this and that etc etc.

I'm just looking for longevity and best preservation of my engines.

So... what to use? Have 3 motors, 140k miles, 220k miles and 280k miles.

PS: I know it's dumb lol but it's gotta be settled.

 

[df2x4]

It is dumb, and it will never be settled.

Personally I use what the owner's manual calls for, at the recommended service intervals. Which for my trucks is conventional 5W-30 every 3000 miles. I prefer Pennzoil, mainly out of habit. Both trucks have been on the same schedule/diet since they rolled off the lot new and I have no engine issues with either at roughly 150K miles. (Knock on wood) I have the oil analyzed by Blackstone Labs periodically and they always tell me there's plenty of life left in the oil and I could push it farther if I wanted.

IMO use what you want and if you're concerned about service intervals or oil degradation, get an analysis done. Blackstone Labs are great people to work with and will explain the results to you in detail.

EDIT - They'll also tell you if there's any other abnormal things in your oil sample, like metal or other fluid contamination.

 

[F4U-1A]

Nothing wrong with synthetic, other then the price. Will not damage old engines. Just get the right OEM viscosity spec for your eng. Now you are in Georgia, was there twice in Atlanta on training with Komatsu, winters down there, will not chill my home brew. You have GMT 400s. Not a Porcha. I switched to synthetic for a quicker warm up in the fall with my 5.7 vortec.

 

[1ton-o-fun]

My 2 cents falls on 2 things I saw with my own 2 eyes. (That's a lot of 2's, lol)

1)I used to work at a Ford dealership that used a '99 Ranger Sport 2.5L, auto, 4.10 geared truck for the parts department. They ordered it new, and serviced it regularly. Same parts manager during it's use, and she was OCD about cars and maintenance. They replaced it with a Transit Connect van after reaching 460k miles. I bought it for $1. Original engine, 3rd transmission. It lost all compression in 2 cylinders at 478+I. It never had anything but Motorcraft Synthetic Blend in it ever. -Nuff said.

2) 25 or so years ago, I was watching NHRA Drag racing and John Force was I the finals. Something happened to his engine during his burnout. You could see it in the exhaust. He ran. He won. His "right out of the car" interview wasn't his usual, it was ONLY about "if you don't believe the Castrol GTX commercials, I had ZERO oil pressure after the burnout and just ran a..." (I forgot the ET), point is, it was the best commercial Castrol could have ever done, but it was real, right there. -Mike drop.

 

[Pinger]

My preferences:
1. Quality pure paraffinic base oil.
2. Synthetic.
3. Standard mineral oil.

The standard mineral oil (due to aromatics and napthenics that are absent in the pure paraffinic base oil) will be prone to oxidisation (sludging, carbon build up, etc). It has good solubility though.

A pure synthetic will lack solubility (the ability to absorb and retain essential additives) and to counter that it will more likely be a semi-synthetic (blended with some mineral oil with its associated problems). It will behave better over extremes of temperature though.

The pure paraffinic base oil has the solubilty of the mineral and the performance characteristics of the pure synthetic.

Pure paraffinic base oils are what synthetics aim to emulate. Sometimes the natural product is better. Scratchy nylon or soft cotton - which is preferable?

But as df2x4 says - this argument will never be settled!

 

[LC2NLS6]

I've heard synthetic helps revitalize old seals. Probably best to change when its dirty and buy it on sale.

I run amsoil in my racecar. Zrod for street and dominator if going racing.

Valvoline syn blend 10-30 in the 454 plus bottle of ZDDP since its flat tappet. I might switch to amsoil zrod as it has zinc in it.

Mobil 1 5-30 in my LSx engines.

Boat gets synthetic valvoline - has roller cam. I might run amsoil OE blend next time.

TourX gets Mobil 1 dexos syn whatever it says to put in it.

 

[DerekTheGreat]

I like watching Project Farm's oil shoot out videos. I religiously ran Valvoline SynPower for years but it seems they've changed the formulation for their 0W/5W-40 and so I switched to Rotella T6, supposedly has more vitamins in it for flat tappet stuff. Also did really well in that shoot out. If I could find Pennzoil Pure Platinum plus in the viscosity I like to run, I'd run that.. Oh, I also add 2oz/qt oil of MotorKote after seeing what that stuff does in a PF video. I do not like non synthetic oils whatsoever.

 

[Erik the Awful]

The tips I've learned over the years:

Break your engine in on dinsoaur oil. After the second oil change you can switch to synthetic.

Lower end oils have more recycled oil in them and break down faster. Quaker State and Pennzoil use a lot of recycled oil, they just have really good advertising. It's fine to run these oils so long as you change them regularly.

If you're maintaining a two-stroke or rotary engine, stick with dinosaur oil, or a very high quality synthetic oil.

I run either Valvoline or Castrol in my Mustang. They're mid-grade oils, but I'm not paying the premium for the high-end stuff.

Blackstone is great for identifying problems before they develop. We send the oil from our race car off for diagnosis.

 

[PlayingWithTBI]

Break your engine in on dinsoaur oil. After the second oil change you can switch to synthetic.

^^^What he said. I've been running nothing but Mobil1, after break in. I used to run 10w-40 in my truck until I bought my Crossfire in 04 - it required the 0w-40 European formula Mobil1. Since it's higher in Zinc and Phosphorus (and I live in AZ) I switched to it. Somewhere around 2009, Chrysler made 10w-40 acceptable so, I switched back. I even ran it in my Infinity Q45.

 

[geeeee89]

When you ask this question you'll always get a lot of technical bullshit that really doesn't matter. just like diesel guys who say "YOU HAVE TO RUN ADDITIVES IN YOUR FUEL OR YOUR INJECTION PUMP WILL BURN UP!!" I use nothing but Castrol GTX conventional oil, always have and always will because that's what I grew up watching my dad use. His 90 model GMC has 278k on it, his 02 Suburban has 370k on it, my uncle uses conventional and sold his truck at 600k.

If you want to waste your money on expensive **** go ahead, but it doesn't matter what oil you use if you maintain your truck properly and do all your maintenance at the scheduled intervals.

That being said, if I went and bought a new truck today I would probably keep synthetic in it. That's what I put in my wife's 19 Tacoma.

I know it's dumb lol but it's gotta be settled.

It won't be settled and it's really a pointless debate. You made it to 280k didn't you? Your truck has obviously been happy with whatever oil you've been using. I'm betting that if all other factors were constant, your truck would've made it to 280k whether you used Mobil-1 synthetic from day 1 or the Walmart store brand oil from day 1. Just change it per the maintenance schedule and it doesn't matter.