Motor oil

My Daughter in Calgary Alb. Canada lost her husband with cancer about a year ago. So I changed oil in her Subaru 6 months ago using a synthetic blend as it was on sale.A few days ago she took it to a Subaru dealer & took along with her the container of the synthetic blend I had used. She asked them to use just regular oil as they wanted over $ 80.00 with synthetic. They told her if they now used regular oil it would ruin her engine.I think her being a woman they are taking her for a ride. I feel sure you can switch from a synthetic blend to regular oil with no problems. I hope Tester will reply to this & others of course.This is not a turbo charged engine.


You can switch back and forth between regular oil, synthetic oil, or synthetic blend oil all you want. If this weren’t true, how would you be able to run a synthetic blend oil which is part regular oil and part synthetic oil?


There is no problem switching between regular and synthetic oils. There is one thing missing in your message. What oil type is recommended by Subaru for your car? The owner’s manual should tell you want type of oil you should be using. Make sure any oil used meets or exceeds the specification listed in the owner’s manual.

Often synthetic oil will allow the owner to change the oil less often (but never less than indicated in the owner's manual.)  Synthetic may be cheaper in the long run.  

I feel for your daughter.  I lost my mother and father to cancer and I am a cancer survivor (over 40 years now).

In addition to finding out exactly which oil is specified, your daughter needs to find a trustworthy independent Subaru mechanic to take care of all her normal maintenance. No reason to use the dealer.

Yes, they are trying to separate your daughter from her hard earned money.
You might want to look in the yellow pages for her area, and talk to a couple different shops, and see if there is one that will take her business from now on.

Then you can tell her you found a great place for her to take her car from now on.

Save the day one more time, Dad.


What your daughter was told regarding motor oil is old, outdated opinion.

Twenty years ago, many folks in the automotive field believed that you could not switch from synthetic oil back to conventional oil without having problems with leaking seals and such. Whether that was ever valid information is questionable, but it has definitely been de-bunked in more recent times.

No matter what type of oil she uses, just be sure that she does not use ridiculously extended change intervals. Many folks believe that they can drive for an incredible number of miles (or months) between changes with synthetic oil, but that does not change the reality that–despite synthetic’s superior viscosity qualities–synthetic oil will become contaminated with dirt, moisture, and combustion byproducts just like conventional motor oil.

I wonder what Tom McCahill, who was the automotive tester for “Mechanix Illustrated” would say about synthetic oil if he were alive today. In his book, “What You Should Know About Cars” which was published in the early 1960s, he advised against using detergent oil. “I don’t want the dirt particles whipped through my engine bearings. I would rather the dirt settle to the bottom of the crankcase and build up a crust just like a good pipe”. Tom also didn’t like multiviscosity oils. He said “10W-30 is a lousy number 10 and a lousy number 30. The real reason for multiviscosity oils is that service stations won’t have to stock as many different viscosities”.

There used to be a myth back in the 1950’s that if you switched from non-detergent oil to detergent oil, it might cause an increase in oil consumption. There may have been something to this, but any time a new oil comes along, all kinds of myths get started.

I switched from regular oil to synthetic and back again on my 2006 Chevrolet Uplander and had no problems. My 2011 Sienna manual calls for synthetic 0W-20, so that is what I use. Our 2003 Toyota 4Runner doesn’t have this requirement, so I use regular oil.

I imagine that by now she has the $80 oil change. This is a good time to find another mechanic to maintain and repair the car in the future. She should ask around and find out which garages are well-thought of. A good garage should be named several times.

I was a Tom fan. I still have two of his “magazine books” he wrote. Not MI, books in magazine format that he wrote from front to back. I am not sure if I have them where I am, or left them in our house in Mexico City. Now you have me motivated to re-read them for the zillionth time if I can find them. He was one cool dude.

He said really funny things, like describing a car that cornered like a weasel in a drain pipe. MI chose not to tell anyone he had died until all his articles were printed, because they knew a high percentage of subscribers only paid to get his stuff.

However, to be fair, in that day and age, I am not sure the oils were that good. They used additives to make them multi-weight, and the additives were still under development.

If I lived in Calgary Alb. I would be using 0w-20 synthetic motor oil simply because it’s a superior product at those extremely low temperatures. That is precisely why synthetic lubricants were developed…

If I owned a Subaru, I would do everything possible to keep to keep my problematic engine alive…

Was it because Sythetic is the recommendation? Is it a turbo? Otherwise they were trying to rip her off and I’d call Subaru Corporate and complain.

“This is not a turbo charged engine.”

You should read the thread before you offer a response…

You enjoyed that didn’t you? Got through first few lines and got pissed cause I don’t like people being shafted. Pulled the trigger a bit soon. I bet it was a 10k oil change. :slight_smile:

Calgary, Alb. Thirty below zero is a nice day…Synthetic lubricants were MADE for people who live in Calgary…Very few grades of mineral oil will flow at -30. Those that DO flow are unsuitable as motor oil…

There may have been some validity in what Tom Mccahill wrote back in this time period. In 1958, GM experienced a number of camshaft failures in the 1958 Oldsmobile. It turned out that certain brands (but not all brands) of multiviscosity oils couldn’t offer enough protection due to high camshaft pressures. Oldsmobile released a statement that multiviscosity oils weren’t to be used in the Oldsmobile engine. My Dad purchased a new Studebaker Lark in 1963 with the 259 cubic inch V-8 engine. The manual specified that non-detergent oil was to be used in the engine. The engine did not have hydraulic tappets. Tom McCahill would have been pleased–his preferendce was for solid lifter.

Just put Mobil 1 in our Nissan, which, from time to time has to sit outside overnight at the ski resort, where -30 temperatures are not rare, and with a 900+ CCA battery the engine fires up right away.

A few years back, EXXON made a presentation called “The Cold War”, where they demonstarated the ability of oil to flow at -30. The best performamer was a 0W30 synthetic, which had a pour point of -45. The 10W30 was like thick molasses and soon fried the valve gear of a Ford Escort engine. In older, looser engines, 0W20 works, but the engine will likely consume oil.

My Toyota has 0W20 synthetic in the winter and 5W30 dino in the summer. Both OK with the Toyota manual. If I drove South in the winter, I would have 0W30 synthetic in the cranckcase, since it would be good for hot or cold.

You used a synthetic blend. That’s ALREADY a mix of synthetic and dino oil. (not that it would matter if full syn was used either) They are feeding her a line of crap. Time for a different dealer.

“You enjoyed that didn’t you?”

Welcome to “Car Talk”!

The dealer, in Calgary, is just trying to do his customers a favor…Overpriced? Certainly. But a favor non-the-less…