downsides to synthetic oil

[grease_monkey]

Originally Posted By: harry j
Originally Posted By: grease_monkey
upside to synthetic oil: better lubricity properties, has higher resistance to breaking down, most synthetics like mobil 1 have high detergent content which means a cleaner engine
downside: it is thinner than conventional which means if your seals are slightly worn it will make the leak even greater. if it is being used in a high mileage it can also burn off faster than snake oil.
My facts are based on experiences. A good Snake oil is castrol GTX and a good synthetic is mobil!
hope this helps




Now with 259,000 miles on my Civic, using the SSO, it burns no noticable oil. The sump is full when I change it at ~3,000 miles.
This wasn't the case when I used Castrol 5W-30 GTX, I could count on burning through a quart or so in those 3,000 miles.

I used to use synthetic oil 10/ 30 in my dodge durango with 138,795 on the odometer it went through 2 quarts of oil between 3000 mile intervals. I have been runing castrol GTX 10/30 for about a year now, and i only go through about 1/4-1/2 a quart of oil between 3,000 mile changes. I speak highly of castrol because it works so well for me

 

[Steve S]

Originally Posted By: BullyT
No downside to synthetic oil. It flows better at low temperatures, it protects better at elevated temperatures, and generally provides longer OCI. Synthetic oil only is recommended for my BMW 740 and I won't use anything else. I also switched from dino to synthetic in my Ford Explorer once I learned more about the benefits of synthetic. Synthetic oil is better than dino. End of story.
What are the recommended oil change intervals recommended by the Mfg.?

 

[Audi Junkie]

The Law of Diminishing Returns kicks-in. Once the oil is "good enough", what is the function of a "better" oil?

 

[virginoil]

REDUCED VARNISH/SLUDGE DUE TO LESS BREAKBOWN OF ENGINE OIL.
BETTER POUR POINT FASTER START UP.
BETTER PERFORMANCE IN EXTREMELY HOT OR COLD CLIMATES.
POTENTIALLY LONGER ENGINE LIFE.
LOSS OF REASONS TO TRADE IN CURRENT CAR.
WIFE WONT LET ME GET A NEWER CAR.

 

[SteveSRT8]

Hey, gents! New poster here.

we run a fleet of GMC Savana vans at 9100 pounds and using PTO's all day long. Some of the hardest duty cycles there are, all are 6.0 gas motors. Rarely even shut off during a normal day, lots of stationary operation at 1700 to 2100 RPM.

I have used synth, mainly Amsoil, exclusively for over 15 years. While it may be true that Dino has narrowed it down over the years, the synth still gives unbelievable protection and our trucks routinely exceed 300,000 miles easily.

Once we wrecked a 2000 model with the old 5.7 (it was over 300k). A friend bought the engine and trans (also synthetic-fed) and runs them in his Buick. Over 50,000 miles more in two years and STILL RUNNING great!

I would never even consider a dino for these applications.

Just my .02.

 

[tonycarguy]

If people answered the OP's question, this would be a one-post thread.

No, there are no downsides to synth engine oil besides price. If they were the same price, dino would be extinct.

Now if you're talking about tranny oil, it's a different matter. Some manual trannies cannot use synth (will grind the synchros).

 

[webfors]

Originally Posted By: tonycarguy

Now if you're talking about tranny oil, it's a different matter. Some manual trannies cannot use synth (will grind the synchros).


What trannies?

 

[Bambam]

Being on the municipal side of budgets and oil,I can hardly make an arguement to use synthetics.I do in my own vehicles,but that is soon to change.

We have a range of vehicles form Honda Accords to 10 wheel dumps. All see varied use and are restricted for the most part to the limits of the town. Extended idle,snow removal,summer asphalting,whatever. Bulk purchased dino and most have 1 year oci's !! Never had an oil related engine failure ever! Just got rid of a 25 year old Mack with 248,000 miles,still running well.

FWIW