synthetic vs "regular" oil change

[wildpig]

for my 2002 pathy, would it be better if i do synthetic change every 6-7k miles vs "regular" change every 3k miles? My driving style is about 20 miles or so each day with 70% highway miles in nice florida weather. Currently has 120k miles

[Towncivilian]

To be certain, you need to get a UOA (used oil analysis) or two. With a good percentage of highway miles though, you'll probably be OK as long as you keep an eye on oil consumption.

Where are you at in Florida?

[yeldogt]

All our company cars that were supplied with regular oil get changed with regular oil in the 5-6k range (recommended weight) - those that were supplied with synthetics get synthetics and have much higher change intervals (and oil capacity) out to 12k and beyond. We actually extend them a little as they age.

We don't see any difference in longevity -- they all last -- and well past 200k.

We have a couple up in the 230k range and I was surprised how the high milage oil quieted down the tiny valve train noise one had (ford dohc v6)

Do whatever makes you comfortable - but it is not necessary to change any oil at 3k - or to change the synthetics at 5k with normal driving.

My Porsche is 20k or two years.

[donald]

I agree with yeldogt!
I used to be one of those "religiously change oil every 3k" drivers.
After hearing some chemical analyses on used motor oil, some studies say that 5000-6000 oil change intervals are perfectly fine, as well as reduces the amount of motor oil pollution.

Although they don't explicitly say "5000mi is fine", they do imply that the 3000-mi rule is outdated due to refinement of motor oil and it's protective agents with all their scientific blabber.
http://www.edmunds.com/car-care/stop-ch ... r-oil.html
http://www.caranddriver.com/features/04 ... ers-column
http://www.cartalk.com/content/features ... s/oil.html

[m0nkeyprince]

just use 5w 30 mobil 1 or any other full synthetic every 5k miles and youlll be fine

[Densetsu]

All our company cars that were supplied with regular oil get changed with regular oil in the 5-6k range (recommended weight) - those that were supplied with synthetics get synthetics and have much higher change intervals (and oil capacity) out to 12k and beyond. We actually extend them a little as they age.

We don't see any difference in longevity -- they all last -- and well past 200k.

We have a couple up in the 230k range and I was surprised how the high milage oil quieted down the tiny valve train noise one had (ford dohc v6)

Do whatever makes you comfortable - but it is not necessary to change any oil at 3k - or to change the synthetics at 5k with normal driving.

My Porsche is 20k or two years.

I just checked the schedule in the FSM for oil change intervals. I've always been changing around the 6,000km mark.

http://www.nicoclub.com/FSM/pathfinder/ ... der/ma.pdf, page MA-7 and MA-10.

Schedule 2, for "regular" driving, has an oil change interval of 12,000km / 7500mi, and on page MA-12 it doesn't say you need to use synthetic to get that mileage out of the oil. (In fact, I believe the owners manual for the '03 and '04 explicitly says do *not* use synthetic oil). So in other words, the engineers at Nissan are saying the Pathy can use the same dino oil for 12,000km, as long as you're not driving under stressful conditions.

That just blew my mind, and I'm not sure if I'd feel comfortable using the same dino oil *that* long. But it's nice to know.

[Towncivilian]

Most people do not drive under "regular" conditions. Severe service schedule for typical drivers - i.e. short trips, heavy traffic, mashing of pedals, rough on the transmission (they don't wait to stop completely after reversing to shift into drive, no use of parking brake, etc) is what I think. Even then, fluids are certainly cheaper than the alternative.

[Densetsu]

In the winter, I'd probably be on schedule 2. My work commute is 20km either way, and I do most of my shopping on the way home -- the engine doesn't cool down much, so I'd still count a shopping trip on the way home as one 20km trip instead of two 10km trips. Most of my other driving is similar; 20km+ drives on highways and freeways, and traffic jams are pretty rare in Edmonton. I'm not a huge leadfoot either, and Edmonton doesn't do much salting on the roads in the winter.

The only time I'd really be doing anything stressful would be in the summer on camping trips, either driving on unpaved backroads or towing a trailer. I'd change my oil more frequently then. But in the winter? By definition I probably qualify for the "regular" schedule, though that whole "oil change at 6,000km" is so ingrained in my mind that I wouldn't feel comfortable after the 6,000km mark.

[yeldogt]

Synthetics are better when you are at the extremes -- but it has to get really hot before regular oil is going to have a problem in an engine. Now cold can be different as the synthetics flow better when cold. I had an Audi that would crank slowly when filled with regular oil at temperatures near 0 F and fire right up when filled with synthetic. So I used synthetic.

Synthetics also have a larger additive pack -- they last longer and are more pH stable - and many have more cleaning agents. But what is the point of having the extra protection if you are replacing it before you even use it.

Today I had all my fluids changed in the Pathfinder. The engine oil at 6k was not dirty and was about 5 months old -- the transmission and especially the transfer oil were clean at 120k. The differentials had been changed at 60k and the oil was fine in both especially the front (obviously) with almost nothing on the plug magnets. My pathfinder really never goes off road or tows a trailer -- and the four wheel drive is only on occasionally with snow. So if you take the truck off road or pull a boat in and out of water -- thats is a different story.

You can easily inspect the engine and transmission fluid using the dipstick.

[miamiheat3332]

Ive been putting valvoline full synthetic 10-30w in mine ever since my free oil change coupon offers ended (around 25k, maybe 30k) and i always change my oil around 3.5k-4k. Highest i ever went was around 4.5k.

Will be at 121000 miles by the end of this week.

[WPGQX4]

Use Amsoil and it will be 25,000km or 1 year which ever comes first.

[miamiheat3332]

Most people found that claim to be bull. And people got their oil tested too, which turned out to be bull. Id run amsoil for a year, maybe in some 1980;s chevy junker. If you care about your car and your engine, you should change your oil at least every 5-6k if you want to push it with synthetic.

[Towncivilian]

I agree with miami. Oil is cheaper than an engine. If I were using synthetic I wouldn't go any longer than 6-8k personally.

[Chuck Tribolet]

I've got 191,000 miles on my '01 PF. I've always run Castrol GTX dino oil. Still going fine. Until recently I was doing about 1/3 of
my miles towing my boat, so did oil changes at 5000 miles up to about 100K miles then went to 3333 miles. Since the towing
is going to be a lot less (boat now lives ten miles from the ramp instead of 50), I'm going back to 5000 miles.

My '95 PF did 130K miles on a 5000 mile change interval, same oil. Towed the boat about 1/3 time starting at about 30K miles.

My '87 PF did 130K miles on a 5000 mile change interval, same oil. No boat then.

My '70 pickup did 100K miles on a 3330 mile change interval on the engine I rebuilt right after I got it. Same oil.

My '72 240Z did 110K miles on an (IIRC) 2000 mile change interval (it was autocrossed every weekend). Same oil.

Good dino oil is fine. Just change it, and change the filter every time you change it. And use good filters. I use Wix.


Read the owner's manual, do what it says.

[yeldogt]

Driving 6k in two years and doing the same distance in 5 months can make a difference. Very short trips in cold weather -- and 10 miles is not a short trip - can cause moisture and fuel to deposit in the oil.

The Nissan 3.5 is a very nice engine and it's amazing how clean the oil is at 6k.

[WPGQX4]

Miami, you may think its bull but until you've seen it with your own eyes I guess there will be no convincing you. As an Amsoil user I'm just giving my first hand knowledge of the product. I could get into detail but they are they ONLY oil that puts a warranty on there product. If its determined that the oil is the cause of engine failure they will pay for any cost to fix they engine. At least they put their money where their mouth is.

On a side note. If you do some research you'll find that manufactuer's are extending drain intervels well into the 10,000km range on newer vehicles. Amasoil has been an advocate for extended drain intervels since 1976.

[miamiheat3332]

i agree with you on the extending intervals on newer cars and such. I believe that and know they also have new oil developing which can be used in those engines to last even a bit more.

My thing is its not much to throw like 25-30$ for full syn and filter every 3 months or so just for car maintenance and such. Our path/q's give exceptional reliability off the lot anyways compared to many other cars. but i want to keep the path for years to come and i just think that regular oil changes and such will definetly keep the engine running top noch and for years to come.

In my case i half the time like to drive my pathfinder hard, other times its nice and smooth.

Same goes for all other fluids, i mean i dont know how many of you guys will be trading it in and such like that, i understand then if your not looking for longevity or dont care. But i just like knowing that everything in my car is changed and fresh and it keeps it running great.

Simple way to look at it is a new opened can of soda. After an hour, it still tastes the same, after 2 hours maybe a little less carbonated but still tastes good, but after like 3-4 hours its flat and tastes like sht. Now just think of that in thousand mile intervals. Particles and such get built up, debris from the road etc.

Im at 121k miles now and the only NON maintenance item i had to replace was at like 60k for the stupid fan control board thing which i just took to the dealer back then and paid like 350. Only other thing was 2 oxygen sensors in the rear banks which i still consider maintenance since they are known on alot of cars to go bad around the 80-100k mark and i changed mine at 88. Other than that its all stuff i wanted to put in or upgraded stuff, and it never gives me a hassle and is running strong (knock on wood).

[wildpig]

i ll take the av of 3700 and 7000 and that will be my new oil change interval with dino oil since i dont drive my car hard and dont tow anything anytime. If i ever get my 350z or g35 will prob use synthetic evry 7-8k miles since i wont be drvin that aggressive anyway

My old 97 PF lasted 211k (and couldve gone easily 300k if i didnt wreck it) on 3-4k dino oil.....