Z Oil Change: Miles or Time?

LinPark

If one doesn't put many miles on a car in a year, is it safe to run synthetic oil based on mileage instead of months? Thanks!

_ace_

In aircraft we use hours of usage as the main measure for maintenance rather than flight miles or time after last installation/rework. If needed, the maintenance intervals in hours are increased or decreased to suit the level of severity of typical usage for that aircraft.

I've often thought of using running time on the Z to measure oil life rather than miles--highway miles are easy on the car but make it look like maintenance is needed right away if you use that figure. On months, you may want to ask Bob the oil guy or another expert. I would figure a year or two wouldn't hurt the fluid, but that's a pure uneducated guess.

The goal is to change your oil and filter out before the oil becomes ineffective as an engine lubricant/etc. The maintenance schedules given to consumers are conservative because people don't follow them terribly closely and they poeple doing the recommendation have to assume a usage spectrum that covers everybody.

If you really want to know a hard and fast rule, look into what breaks down, get an oil analysis of your used oil, adjust your cycle, and then get a second oil analysis to confirm you're good to go.

MattP725

IMO it isn't worth the battle with Nissan if someone happens to your car. $40-50 every three months isn't a huge setback for most people. Can you extend it to 4 or 5? Sure but if something happens to your engine there is a descent chance Nissan will want records of your oil changes to warranty and that might come up.

Warranty aside, my Chevy Trailblazer specifically said in the manual to change the oil either when the oil life monitor said to, or every year, whichever comes first. It did hold 7 quarts vs our 5 though.

Davey

The "normal" maintenance schedule is 6 months/7500 miles.

If it's been 8 months and 2500 miles, I'd laugh in their stupid faces if they even tried to insinuate it was an issue.

roy'sz

Every other type of measurement is in engine hours. Boats, pumps, motors etc. are all measured with run time not storage time. Something to remember is if you keep your car stored in a tempature that stays the same and is a dry or dryer climate then you can stretch your time of oil changes. If it gets hot and cold cycled often you will have a little bit of moisture build up but you should start the car and let it get up to operating temp atleast every other week to ensure the seals don't dry rot on you and you don't get hard spots in the tires. That is my 2 cents worth.

Dark Sarcasm

whichever comes first

__________________
wax

nabenson

This.

If you do not drive your car long distances, letting it fully warm up (20 minutes per trip) then your oil eventually becomes heavily contaminated with water. This water comes from the intake, straight out of the air it is sucking in.

This is the reason for the time limit in addition to a mileage recommendation. If you drive few miles, but always drive for say an hour at a time then you're fine to extend the time, but otherwise I would just change it on the time mark or the mileage mark.

FricFrac

Uh I don't think that's quite right.... intake air goes into the combustion chamber and back out the exhaust. Precious little water gets in that way. If it was as heavily contaminated as you suggest you'd have milky oil all the time. Typically condensation is where most of the moisture comes from that gets in the oil. If your car sits for extended periods of time you're more likely to have extra water in your oil.

Water from condensation is why you should change your oil if your car is off the road in the winter - simply change the oil in the spring when it goes back on the road. In the winter turn it over every few weeks to keep the seals oiled. Putting oil in the car for storage doesn't make any sense either since you're not going to drive with the "storage" oil so just leave the oil that's in it when you park it.

__________________
'09 370Z - '93 300ZX Vert - '83 280ZX - '83 280ZXT -'81 280ZXT stroker - '72 240Z - Stillen CBE, HFC, G3, Grounding Kit, Sways // Swift Spring // H&R 15mm // 5% Tint // Clear Bra //

Dark Sarcasm

i have said it before, i think oil changes should be measured by RPMs not miles. I believe this is how Hondas oil metering works, the computer counts the engine revolutions and when it reaches a certain number the "change oil" reminder starts blinking. I saw a Honda truck go over 10k miles before the reminder turned on, and Honda stood behind it. They said change the oil only when the truck tells you to.

I change my oil (mobil 1) every six months but i only drive 10k miles a year. Last time i had it changed, the oil came out a nice gold color, and it was still transluscent.

__________________
wax

LinPark

If you only drove 2k miles a year would you still change it every 6 months? Doesn't that also mean you should check the date on the oil when you buy it? What if its been sitting on the shelf for like 6 months?

Also, on the Honda item I'd be shocked if it uses RPM's - I'd bet it uses miles because my indicator drops to 15% at precisely 6k miles each time. I've been sending the oil into Blackstone Labs and have gotten to the point where I run the oil for almost 8,500 miles and it could go further (this is just basic Honda Oil) - so I have to believe that I could run Redline longer than that in a 370Z.

I suppose I could take a sample of the oil from the 370Z and send it in without changing the oil. I've had this car for 2 years now - I changed the oil once with Nissan Ester at 1,100 miles and switched to Redline at 3,100 miles on 3/5/2011 - the car now has 5,900 miles but I haven't changed the Redline oil yet. Seems kinda sad to spend that much on oil and only use like 35% of its life. Guess I'll send it in to Blackstone Labs and ask them how it looks. I'll report back what they tell me.

Davey

Exactly!

The time recommendation is based on the idea that if you go less than 1,000 miles a month, you are probably doing lots of short trips and never warm the oil up.

I drive my car at least 30 minutes on the highway at 70+ MPH every time I drive it, it's not a problem.

roy'sz

[QUOTE=LinPark;1639485]If you only drove 2k miles a year would you still change it every 6 months? Doesn't that also mean you should check the date on the oil when you buy it? What if its been sitting on the shelf for like 6 months?

It doesn't matter how long oil has sat on a shelf, being that it is vaccum sealed from factory it wont collect moisture. HOWEVER, when you open the oil and remove the seal and don't use all the oil (1/2qt) that is when moisture will build up.

ZMan8

there is the issue...we need 5 and 1/8 qts which means you will always have remaining oil sitting if you do your own oil changes

__________________
2010 370Z 40 Anniv., 6 MT | Fast Intentions | Swift Springs | SPC | Z1Motorsports | JWM | Redline Oils | 35% Window Tint
2015 Mazda6 | 370ZChicago: Chicago Area Cars & Coffee

ZMan8

I never thought about checking date on oil bottles ...what's considered bad. I do oil changes twice a year (when I take it out and when I put it back in storage) but I buy oil once a year because bulk is cheaper.

__________________
2010 370Z 40 Anniv., 6 MT | Fast Intentions | Swift Springs | SPC | Z1Motorsports | JWM | Redline Oils | 35% Window Tint
2015 Mazda6 | 370ZChicago: Chicago Area Cars & Coffee

roy'sz

hmm, i do 5 solid and never use the "1/8" and it is always at the high mark dead center in the middle of the drilled hole. honestly the 1/8 doesn't matter.