Contour Enthusiasts Group Archives Forums General General Long Oil Change Interval

Here is the Lab data for the long change interval on the wife's Z24. (2.4L DOHC I-4)

Mobil 1 5W30 Oil & Bosch synthetic media filter. (K&N drop in for air)

It went 6 months and over 9500 miles.

I am posting this for all the folks that claim they "HAVE" to change the oil every 3 months or 3000 miles whichever comes first no matter what.

Starting with an excerpt from the comments from the technician:

"We didn't find much if any change in the sample compared to your last one, which is most impressive considering the oil was in use about 3300 miles more. No contaminants and air & oil filter are working exceptional."

This list will include normal wear metal amounts followed by universal averages (based on a 3k mile change btw)

Aluminum: 3 / 3
Chromium: 1 / 1
Iron: 20 / 18
Copper: 8 / 5
Lead: 3 / 4
Tin: 0 / 1
Silicon: 8 / 9

All other trace metals at 0.

Besides the "additive" elements found in the oil of course.

SUS Viscosity: 60.2 (55 low - 62 max)
Flashpoint: 390 (low > 365)
Fuel: less the .5%
Antifreeze & Water: 0
Insolubles: .3%

It looks like their previous recommendation of 10-12k is plenty safe. I think I'll stay at 5-6 months. I don't like past 4 months really but circumstances dictated a longer interval this time and now I know that's well within the safe range.


The SVT will stay at 4 months.
Matter of fact I will be changing that in the next week or two and getting my first sample on the 3L. It probably won't be a good baseline though since the engine has so few miles on it. (over 7k since rebuild and ~13k total miles) It will show how well the oil is holding up though. The 2.5L was VERY HARSH on the oil.

Nice writeup. I am actually at almost 5 months on the SVT with probably 5k miles. Mobil 1 5w30. I'll be changing that out this weekend though. Maybe I should run a sample down to blackstone labs, as it's about 5 miles from my house

Mark

That just reaffirms my belief about Mobil 1. I remember when Mobil 1 came out on the market, they said in their ads that you could go 15,000 miles between oil changes. Now you don't see them quoting any kind of mileage. I contacted them and asked them a couple of years ago what they recommend for oil change intervals and they wimped out saying to go with the manufactureres recommendations. I change my Mobil 1 every 10,000 and the oil filter every 5,000 miles. At 5,000 miles the oil is just getting that brown tinge to it. At 10,000 its looks black like normal oil at 3,000.

Well, it's a known fact that the manufactureres recommendations of 3000 miles per oil change is more of a dumb safty rule for the average car. It depends on the age of the engine, weather/heat, driving styles/wear ect. I don't normally have my oil changed right at 3K. For me I just keep an eye on the color of the oil. If it starts to look bad right at 3K then I have it changed. If I've been driving around all winter and it still has a nice color then there should be no rush. These days though you will find that VCT engines might need to be changed at 3K no matter what though.

I remember readings somewhere where these NASA guys / OIl freaks would go a whole year on Mobil 1 and just change the filter at 6 months. I'm still gonna do the 3months or 3k miles...I have too much $$$$$ invested in my vechiles :-) Plus they live hard lives already.

www.bobistheoilguy.com rocks. FWIW I just had my SVT's oil analyzed. Looks like around 7000 mi. would be safe. Not sure if I'll take it that long anyway, though.

I use mobil 1 in my ATX and Amsoil 5w30 in the crank. Woud it be safe to assume that i will be getting similar benefits of longevity from Amsoil without having it tested?

I change mine at 3k or so mainly because I do almost all city driving. Also I start the car and shut it off a lot daily so heat up cool down breaks down oil. Now my grandparents with their 03 Interpid go 7000 between oil changes, mainly city and they dont have any problems.