Hawk59, I’d Get Another Mechanic’s Opinion. Who Knows If The First Opinion About Sticking With Synthetic Makes Any Sense ? Then You Could Get A Third Opinion To Check On The Second Opinion . . .
If it helps, you could post the question on the Car Talk Community site. You’ll get lots of opinions there and it will save you some time.
CSA
Blackstone can test the oil for oxidation, but I believe you have to pay a bit extra for that test. There are a couple other labs that include oxidation testing in their base price, and should be competitive with Blackstone’s prices.
But, you can get around this one test by looking at the viscosity of the oil, which is included in the base price. They list the oil sample in the viscosity that it tests as, and also shows you a range that oil weight should be within. If its too thick, then the value will be higher than the range.
Yes, there is a direct link between additive life and sludge formation.
Basically, once the calcium runs out, and the oil starts to oxidize, it will start to thicken.
Oil can’t really turn to sludge without something in it causing the contamination.
Oxidation is the primary cause. Fuel contamination will lower the flash point of the oil, which will encourage oxidation. Loose piston ring clearances will encourage blow by contamination, which also contributes greatly.
BC.
Using Synthetic oil in snow blowers and lawnmowers is probably the BEST use for it. Since most people usually only change their oil once a year (at the start of each season)…the cost difference between full synthetic and conventional oil adds up to about $3 per outdoor equipment/year. It’s a no brainer.
With a snow blower/generator synthetic makes a lot of sense when trying to pull start the motor stone cold in the middle of the winter.
I cheaped out one year and bought regular oil and pull starting a 12HP motor @ 0F is very hard. This year synthetic and it pulled easier.
BC,
Thanks for the explanation. Much appreciated.
It’s only real advantage is that synthetic lubricants have a much broader viscosity range than mineral oil. As temperature changes, viscosity changes much less with synthetic oils…This has a great advantage during severe cold weather when they are able to maintain their ability to flow better than the best mineral oils…
Are they a better natural lubricant? No…
Can they absorb more contaminants before they start “sludging up”?? Never demonstrated…
“Synthetic oil is more stable at high temperatures. Conventional old-fashioned oil breaks down faster at high temperature than does modern synthetic oil.”
But under normal operating conditions, even high-speed desert driving, motor oil never reaches these extreme temperatures…
Irlandes is one of the very few posters here who has actually tested the oil condition and determined the change interval BASED ON HIS DRIVING PATTERN. His 8800 miles between synthetic oil changes in the Southern states and Mexico is right on. However, that does not mean the a short trip commuter in Minneapolis who parks outside can do this. Cold weather really promotes sludge, so the change interval has to be shorter.
Some cars do just as well on dino oil as synthetic, although synthetic would allow a slightly longer drain interval in very hot or very cold weather. Whether that justifes the extra cost is up to the driver to decide. We use Mobil 1 for winter driving and normally switch back to EXXON dino 5W30 in the summer.
We have tested our oil and it would seem that 5000 miles on dino oil is OK and we might go 6000 on Mobil 1 as well.