I don't know much about cars besides how to drive them, but my father gave me his 2005 Chrysler Crossfire as his age and health make it difficult for him to get in and out of it. It runs like a dream and is a lot of fun. I've had it for about a year, but in that year I have only driven it about 7,000 miles. It has 115,000 total miles on it.

It requires synthetic 0W-40 oil and takes 8.5 quarts of it, which amounts to about $130 every oil change. The owner's manual says to change it every 6 months/6,000 miles if primarily driven on the freeway, which it is. So far I have changed the oil every 6 months, even though one time it only had 2,500 miles on it (didn't drive it much in the Wisconsin winter). My question is, in those low-mileage circumstances, do you really have to change the oil every 6 months even if you haven't put many miles on it?

I really like the car and want to "treat her right" (e.g., high octane gas as the owner's manual insists, etc) but don't want to do unnecessary stuff...


  • 1
    You should definitely shop around. Full synthetic Mobil1 0W-40, 5 quart jug is $37. So the oil plus filter should only run you $78. That's all in US dollars. I don't know how much it will fun where you are, but Amazon should be pretty universal.
    – cdunn
    Jun 12, 2017 at 17:32
  • Agree with @cdunn, you're paying too much for 0W-40.
    – barbecue
    Jun 12, 2017 at 19:37
  • I went to two places and they both charged the same amount. Next time I'll order my own and bring it with me.
    – theglossy1
    Jun 12, 2017 at 20:04

3 Answers 3


It may be more cost effective for you to switch to a fully synthetic formulated for extended life, something like AMSOIL Signature Series 0W-40 Synthetic Motor Oil.

enter image description here

Under normal driving conditions, it is rated for 25,000 miles or 1-year, whichever comes first.

I am not a dealer or rep, just have used this successfully for years.

  • So this is better than Mobil?
    – theglossy1
    Jun 12, 2017 at 15:09
  • In my opinion, yes, but that is all it is, an opinion. Mobil has also come out with an extended life blend. I believe many synthetics can go longer, but manufacturers make more money when you change them more frequently. Also, spend the money on a good filter.
    – CharlieRB
    Jun 12, 2017 at 15:14
  • I feel like this answer is oversimplified. You've identified an oil that should last just fine for 1 year or 25k miles, but what about the filter? Also, it would be ill-advised to start utilizing extended oil changes without doing an oil analysis now or at least after the first oil change to determine what shape the engine is currently in, and if it would take well to a different schedule.
    – atraudes
    Jun 12, 2017 at 20:38
  • 1
    @atraudes I scrolled up and down and did not see your detailed answer here. Maybe you should write one since you believe mine is oversimplified.
    – CharlieRB
    Jun 13, 2017 at 11:23
  • 1
    I appreciate the effort. You may want to use the words "may I suggest", or something of that nature, since your comment reads very much like a criticism. Do you have some reference backing your claim on oil analysis prior to using extended life oil? I am more than happy to add your advice if you have something valid to reference.
    – CharlieRB
    Jun 13, 2017 at 18:15

Send a sample of your oil off for an Oil Analysis (Blackstone Labs and AMSOil are two companies that do this).

They will give you a scientific opinion on the oil, your engine, and when they believe that you should change your oil. Cost about $30, but if they say that you can stretch your oil changes, it will end up saving you money.

  • 1
    Wow, fascinating concept.
    – theglossy1
    Jun 12, 2017 at 19:03

Actually, it goes the other way; The less you drive the more often the oil should be changed. This is more severe in cold climates. Short driving periods, like 10 minutes are the worst. Some years ago, the toughest API test (that is the rating you see on the oil) was #5 the "Aunt Minnie" was a 5 minute run then a 1 hour wait in a 32 F test cell (if my memory is good). The oil weight/viscosity may be a typo; I would expect 5W30 or 10W40. I change my 5 qt and filter for about $30, maybe you should shop around. At the risk of edit; Regular motor oil testing would run 50,000 in taxi cabs with good results; it is always hot so, no water condensation.

  • Yes, stick to the stated interval. I did on one car double the interval for the oil (was doing lots of long runs...) but changed the filter more often. The filters were so cheap but the oil was expensive : synthetic 5W50 - worked fine.
    – Solar Mike
    Jun 12, 2017 at 4:09
  • 1
    A little research always helps when answering. The OP is referring to synthetic oil, which is more expensive than the traditional blends, as well as requiring 3.5 more quarts than your vehicle. Also, 0W-40 is a real viscosity rating for synthetic blends (mobiloil.com/en/motor-oils/mobil-1/mobil-1).
    – CharlieRB
    Jun 12, 2017 at 12:55
  • 1
    @blacksmith37 You shouldn't assume there was a type-o. From the manual: “For best performance and maximum protection under all types of operating conditions, only use synthetic engine oils, approved to MB 229.3 or MB 229.5, such as Mobil 1 SAE 0W-40.”
    – theglossy1
    Jun 12, 2017 at 15:08
  • Guess I am getting old; I didn't realize there was a 0 viscosity in motor oil. Hopefully , I can legally say when Mobil 1 came out in the '70s , it was cutting into Amocos business. So the testing i referred to was part of Amoco evaluating synthetics. Jun 13, 2017 at 15:31

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .