Synthetic vs traditional motor oil

[MacTavish]

Consumer Reports did a study a few years back using NY city taxis with new 6 cylinder engines. The purpose of the study was to debunk the 3000 mile oil change recommendation and add credence to the longer mileage recommendations found in owner manuals. They used both synthetic and natural motor oils, and changed the oil every 6000 miles for 60,000 miles. They reported that there was no difference in wear between the natural and synthetic oils, and that many of the taxis in the test actually ran 24 hrs/day for most of the test period.

 

[Bottoms polaris]

Amsoil all the way.

 

[sniper22]

Conventional--run for 5K, Synthetic 7.5K.
I've used Motul, Pennzoil Platinum, Valvoline Synthetic, G-Oil (made from animal fat).
Higher iron in Mobil1 used oil analysis keep me away from M1.
I buy whichever synthetic (except for M1) is on sale and do not pay more than $5 for conventional, $12 for synthetic. Still using up my Free After Rebate G-Oil stash.
Pure1 or Bosch (same as pure1) filters with synthetic ADB valve.

Starting a car, without a block heater, at 20-30 degrees below 0 for 3 months every winter made me believer in synthetic oils.

I love the G-oil but ran out of rebates and the man I bought my current truck only ran M1 so I haven't changed(yet).

 

[Old_School]

I've considered using synthetic over the years, but have never been able to justify the cost. I've never had an engine failure in all the years of owning cars using Dino oil at 5k-6k mile oil change intervals.

Ran into a guy 20 years ago who was driving a Nissan Sentra with over 425k miles on the original engine. No smoking tailpipe and he claimed he only had to add a qt of oil every 6k-7k miles. When I quizzed him about using synthetic oils or frequent oil changes, he told me he used Dino oil and changed it every 15k miles! Said he changed it every 6k miles until he hit 200k on the odometer, then decided that as clean as his used oil was, he would stretch that to 10k mile intervals. At around 275k, he started stretching it to 15k mile intervals, with no ill effects...he did say that he had gone through 3 manual transmissions, though.

 

[Jeddak]

it all depends on the mileage and the type of vehicle you put it in...the higher the mileage the more likely you will develop leaks as seals tend to expand with syn oil cars that have traditional oil need to have the oil changed to syn oil after 20k after the motor has broken in but older engines have looser tolerances and thicker oil is needed to provide the hydrodynamic wedge in the bearings, newer cars have better seals and tighter clearances (except dodges) you could park a ship between those clearances...the syn oil doesnt break down as fast as traditional so you can go longer between changes

Have you ever been to BITOG? Heavily moderated, but fascinating site about oils and lubricants.

Synthetic oils do not expand seals. If anything, esthers have natural cleaning abilities and they might clean the crud left by conventional oils. PAO synthetics do not have the same ability, so they rely on additives to clean. If synthetic base expanded seals, wouldn't engines leak less after switching to synthetic?
I am running Motul 8100 5w-30 in new to me Toyota. Switched at 146K. Unknown oil history prior to me. No leaks. Ran Maxlife with MMO for an easy clean on the first oil change, now Motul with MOS2. 700 miles into the oil change---no problems.
Great many new cars come from the factory filled with synthetic oils. Engines break in just fine.
Loose clearance on Dodges????? Really???? I guess I should be running 10w-50 in my Pentastar, and not 5w-30, like recommended by the manufacturer. There are 5w-30 oils that almost as thick at operating temperatures as 5w-40, like G-oil, and other 5w-30 that are almost as thin at operating temperature as 5w-20, like Valvoline.
Synthetic base, usually, has better High Shear/High Temperature numbers and does not get cooked by hot spots in the engine. This is due to them not needing as many friction modifiers, so synthetics stay in grade longer, and do not thin out at the end of the service interval. Synthetics usually have a more robust additive package as well. Higher price allows for more expensive additives.

Not directed at brad. Put a bottle of conventional and syn oil in the freezer. After 2 hours pour both in your car. Which one do you think will flow better? Syn will flow at much lower temperatures than dino ( I experienced it first hand in Alaska) and it can take higher temps better, so if your engine tends to run hotter, use synthetic oil.

 

[Old_School]

Have you ever been to BITOG? Heavily moderated, but fascinating site about oils and lubricants.

Agree. BITOG is a great site.

Not directed at brad. Put a bottle of conventional and syn oil in the freezer. After 2 hours pour both in your car. Which one do you think will flow better? Syn will flow at much lower temperatures than dino ( I experienced it first hand in Alaska) and it can take higher temps better, so if your engine tends to run hotter, use synthetic oil.

If I lived in a cold climate, I would definitely run a synthetic! Same with a turbocharged engine...don't want oil breakdown/coking in that turbo.

 

[brad sweet]

Have you ever been to BITOG? Heavily moderated, but fascinating site about oils and lubricants.

Synthetic oils do not expand seals. If anything, esthers have natural cleaning abilities and they might clean the crud left by conventional oils. PAO synthetics do not have the same ability, so they rely on additives to clean. If synthetic base expanded seals, wouldn't engines leak less after switching to synthetic?
I am running Motul 8100 5w-30 in new to me Toyota. Switched at 146K. Unknown oil history prior to me. No leaks. Ran Maxlife with MMO for an easy clean on the first oil change, now Motul with MOS2. 700 miles into the oil change---no problems.
Great many new cars come from the factory filled with synthetic oils. Engines break in just fine.
Loose clearance on Dodges????? Really???? I guess I should be running 10w-50 in my Pentastar, and not 5w-30, like recommended by the manufacturer. There are 5w-30 oils that almost as thick at operating temperatures as 5w-40, like G-oil, and other 5w-30 that are almost as thin at operating temperature as 5w-20, like Valvoline.
Synthetic base, usually, has better High Shear/High Temperature numbers and does not get cooked by hot spots in the engine. This is due to them not needing as many friction modifiers, so synthetics stay in grade longer, and do not thin out at the end of the service interval. Synthetics usually have a more robust additive package as well. Higher price allows for more expensive additives.

Not directed at brad. Put a bottle of conventional and syn oil in the freezer. After 2 hours pour both in your car. Which one do you think will flow better? Syn will flow at much lower temperatures than dino ( I experienced it first hand in Alaska) and it can take higher temps better, so if your engine tends to run hotter, use synthetic oil.

true but older cars as i am used to dealing with syn oil will slip right by most higher mileage seals...as you stated newer cars such as my Honda are and were designed with syn oil in mind,cars with variable valve timing benefit from the higher sheer rate,Toyota with notoriously small clearances benefit from syn oil most engine manufactures will design the lube package around the smallest tolerances the engineer specs to them...but the average joe putting syn oil in his chevy truck with 100k will notice the rear seal starting to leak just after using syn oil..and i would bet in alaska you were using 0/50 or o/30 just to keep them going and yes syn oils dont break down additives as greatly as dino oils

 

[BHJ]

Mobil 1
If it's good enough for the space shuttle, it's good enough for my ride

 

[brad sweet]

Mobil 1
If it's good enough for the space shuttle, it's good enough for my ride

yep use ow/ 20 in the Honda(spec) and dexos in the 2500 HD good stuff

 

[the_great_white]

Valvoline Syn Blend every 5k on a '06 F-150 5.4 once the factory warranty ran out at 60K. just hit 160K and no issues and i do a lot of towing