How many kilometers can one go between changes with synthetic oil, let's say Castrol Syntec, if that makes a difference? Regular oil, I usually can go 6000km. I just got an oil change at Costco where they were doing a synthetic oil change for the same price as regular elsewhere. They were saying they still recommend 6000km, but they think it can go upto
8000km. What's the general consensus here?
Follow manufacturer recommendations. New Subies require synthetic, don't they? So do what the manual says.
Hi, I hope you are aware that the "fake" synthetics, also known as "full/fully synthetic" are just highly refined group III basestock oils (read: no significant amount of either PAO, or ester, di-ester) complemented with a strong detergency or add pack.
This means lower flash point than a true synthetic, and more deposit formation than a true synthetic,
-that's why more detergents.
With a "fake' synthetic I'd go no more than 4000 miles, on a new non-turbo Subie.
Here's my personal account:
My 2000 Impreza L Coupe since new was always fed Mobil 1, at +/- 3,333 mile change intervals, I do a lot of higher rpm, mountain driving. At that interval the oil would always come out dark brown. Since around 2006 it started getting progressively dirtier, ...at 2500 miles it would get dark brown, and from there quickly start turning blackish. My driving style did not change. I blamed it on the aging motor, blow-by etc., and started using an extra capacity oil filter to counter the development.
Recently, I switched the car to Redline ester oil. The first change at +/- 3,333 came out just as dirty, but esters are known to have strong cleansing action, then my second change with Redline at nearly 3500 miles came out fairly clean.
As Redline is expensive, and after giving the engine two cleaning changes with this ester oil I went back to the usual Mobil 1.
Guess what? My oil is getting real dirty again at currently around 2100 miles. It seems to me the new Mobil 1 oil formulation is to be blamed. Old formulation PAO Mobil1 was a superior oil, new formulation is much lesser.
Again, my suggestion is not to use it at more than 4000 miles. I know I would never go beyond that interval. Just don't feel comfortable, but people report UOA (used oil analysis) showing that Mobil 1 it is still good at that milage in non turbo engines.
Basia
It's not specifically about synthetic oil, but there happened to be an article about vechile servic Most petrol vehicles should be able to go at least 12 months or 10,000km (whichever comes first) before changing the engine oil and filter, provided the correct gradde and quality of oil is used.
Life-long coolant can mean a 10-year life span, while transmission fluid does not require replacing as frequently as it used to. Your service provider should be aware of these things and only make recommendations on an as-required basis.
It of course depends on how old and well-maintained your car. He is talking about relatively new cars, not a 1950's rust-bucket that leaks oil like a sieve. :-)
Well, mine's a 2008 model, it's not specified to use synthetic, though I suspect it's pretty much the same as the 2011+, which is apparently specified to use synthetic.
Yousuf Khan
Well, where does Castrol Syntec fit into that fake vs. true side of things?
Yousuf Khan
Castrol?
Isn't this the company that started the "fake" synthetic marketing scam, for lack of better a word? In the US market at least.
If it were me I'd use only German sold Castrol as in _retailed_ in Germany or for sale on the German market. Supposedly, you cannot label and sell modified group III oils as synthetics there, it has to be the real thing.
Basia
Re-definition to avoid mis-representation, would be the precise term, ...as they (Castrol) helped re-define what a synthetic oil could be called without misrepresentation.
Just the other day I've seen a bottle of NEW Castrol Edge EP or Extended Performance oil selling at Wallmart for 8+ dollars. Said on the bottle "good for 15,000 miles." Makes me wonder. Not a word of what this new concoction consists of. Probably same old stuff, ...maybe with some added zinc, less likely some miniscule amout of PAO.
Basia
Just about what I'm doing now. I do change twice a year even though going less than 10,000 km (6,000 mi). If shop puts on smaller filter that I can't get off, I just change the oil without changing the filter.
You have to watch shops or dealers pushing too frequent service or service not specified by the manual. I got stung once just dropping my Forester off and letting them do their 30,000 mi service which included an unneeded engine flush.
Now when I take it in or my wife takes in hers we ask them to only do manual specific items and call us if they think anything else is necessary.
It MAY have been un-needed - but if it had been done on all of those Toyotas, VWs and Chryslers that died early due to "coking" most of them would have survived.
Tell that to Coca-Cola ... "Coke adds life". ;-)
As an apprentice I was working on a real clunker when the coke guy showed up to fill the cooler. I asked him if things really DID go better with Coke, and when he said "yes" I said "give this thing a Coke"
Never thought of the cost of synthetic oil but talking to my son yesterday about oil change in his Mercedes, it costs about $8 quart. He says dealer will change it annually for about $200 but he has a shop that charges $100 and to do it himself would cost about $60.
An annual oil change of $200 is not so bad. I understand BMW's require a semi-annual oil change of $200, which is getting up there in price. I do currently, quarterly oil changes on average (3 months/6000 km).
Yousuf Khan
My younger sons both had BMW's and maintenance cost was a driving force to buying something else. Son with Mercedes also had a Porsche with expensive oil changes. His wife has a Forester and I think he's eying a new one for himself after the Mercedes.
Other son traded his BMW for an Infinity and also has a Hummer.
Neither son does any car work himself.
Obviously car costs are not as important to them as they are to their old man ;)
Synthetic change with Motorcraft filter on my 4.0 liter Ranger costs me less than $40. I buy my oil 5 gallons at a time when it is on sale, and filters 5 or 6 at a time as well when on sale.
Like most places, car service centres charge WAY too much (a large portion of which goes into management's pockets rather than the actual person doing the work!), but that $100 one looks better by the time you add in all the extra things. It might cost $60 for the oil to do it yourself, but then you've got to add in your time to actually do the job, clean up afterwards, dispose of the old oil, etc.
Begs the question of what a semi-synthetic oil is nowadays. A mix of group II and group III basestocks?
No wonder some of the better formulated conventional oils start out-performing "modern" semi-synthetics.
"...Chevron documented examples of the competitive semi-synthetic performan ce myths in multiple areas versus its premium formulated Delo 400 LE 15W-40 . In these tests, the Delo 400 LE with ISOSYN Technology performed equal to or better than many leading semi-synthetics. In one test designed to look at soot related wear protection, Delo 400 LE significantly outperformed 3 o f the 4 semi-synthetics tested, showing between 16-41% better wear protecti on in this test. Tests for oxidation and deposit control also showed very g ood performance results of Delo 400 LE versus the four major oil companies' semi-synthetic products."
The point I am trying to make in this thread is not that fake synthetics are necessarily bad oils, per se, ...they are good, i.e. better than conventional, but they are grossly overpriced for what they truly are, and I would be very careful about extending drain intervals with them.
4000 miles in my book is tops! (I do a lot of high speed, moutain driving)Basia
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.