The DEFINITIVE answer on Oil Change Intervals (NOT)

Messages
1,432
Location
Virginia
I read this post on another forum (Car Talk BB). The thread was about how often oil should be changed:
quote:
oil change schedules and maintainence schedules are mostly bogus. They are scheduled according to averages. The only true application I have seen of most scheduled service intervals is being used by the warranty company to deny service for lack of scheduled maintinence. Oil change intervals are dependant on the amount of internal engine friction, amount of contamination from blowby gases, operating temerature, Type of lubricant used, and engine temp. I have never followed the schedule with regular oil. I have had several vehicles run fine in excess of 300,000 miles by looking at and feeling my oil on a weekly basis. Standard oil shows it's need to be changed through appearing dark and burnt and feeling thin and somewhat gritty. Synthetics are supposed to last longer and I imagine they do not show signs of breakdown as redily as regular oil does. Still if the synthetic feels gritty and or appears opaque black it means it has alot of carbon in it and should be changed. If the saturn manual says 7,500 miles and also says use synthetic only. Then you should use the synthetic reccomended. If the dealer you took it to filled it with 5w30 quakerstate than you will be needing it changed sooner more like 3,000. If the car is used and engine wear is unknown you'd be well advised to have an experienced mechanic look at your oil a few times to get an idea of what is a good interval for your vehicle. Engine wear, driving style, operating condidtions, and the type of oil used all contribute to the life of the lubricant.
Please retract everything I've ever said about the possible inaccuracies / uncertainties of lab analysis...anything has to be better than this guy's "how does it feel" test. Can you imagine going to a mechanic "Hey, can you feel my oil?" You'd either get punched out or arrested.
 
Messages
3,704
Location
Chattanooga, TN
Difference is that no doc would even hint at a diagnosis without the tests due to malpractice yet many garage mechanics would offer an opinion without hesitation. (it would probably be you are in the shop why not change it now) Actually, you can get some feeling (indication) of the oil by looking at it and feeling it, (condensation, coolant, grit, etc) not a great test but just an indicator.
 
Messages
233
Location
Midwest
Changing when it "feels" thin between the fingers!!! This has got to be the dumbest thing I have ever heard any "car-guy/gal" say.
 

Patman

Staff member
Messages
22,012
Location
Guelph, Ontario
quote:
Originally posted by dagmando: Changing when it "feels" thin between the fingers!!! This has got to be the dumbest thing I have ever heard any "car-guy/gal" say.
Unless he's got a TBN reader on his fingertips! [Big Grin]
 
Messages
3,333
Location
Bolivia
That has always been the standard practice here. Mechanics use their "dedimetro". That can be translated into something like fingerometer. To prove to one that his was not working I sent his 15w40 oil to the lab at 6,000 km when he insisted it was good. It showed 14.0 viscosity, but 60% oxidation, 6% soot, 6% diesel fuel. It had also probably sheared down, as that brand does regularly here.
 
Messages
57
Location
Leesburg, IN
well, I fully aggree that proper analysis is VERY important, you CAN tell a difference between nasty old oil and good new stuff. Exactly how much that really tells you I dont know. I dont know how "black" it can get. Nor do I know what it looks like when its "already too far gone" If this guy really has taken a few vehicles to over 300k thats a very astute acheivement. But my logic side still wants to see some hard data.
 
Messages
8,467
Location
Colorado
Matt89, as a Saturn owner I can tell you that what this guy is saying is nonsense, unless there has been major changes involving Saturn oil recommendations in the past couple of years. The owner's manual for my 2001 Saturn SL2 recommends 0W-30 (in severe cold), 5W-30 (preferred), and 10W-30 is also allowed. This is the first time that I am aware of (in the 2001 owner's manual) that the word synthetic is even mentioned (it says you can use a synthetic in severe cold). The older Saturns I owned had recommendations for 5W-30 (preferred), 10W-30, and straight 30 wt (no longer allowed). At my dealership if you mentioned synthetic they discouraged the use of synthetic. I was told that Saturn at the factory uses Quaker State motot oil. As far as I know at the dealership they were using Quaker State. They also encouraged the use of a graphite containing oil supplement. If that guy is saying anything to the effect that Saturn encourages the use of synthetic oil, then there have been major changes at Saturn in the past two years, because synthetic oil was never even mentioned until the 2001 owner's manual and the use of synthtic oil was not encouraged, at least at my dealership. Saturn also, at least in the past, wanted a person to do 3000 mile oil changes. They did not say change your oil when it gets black.
 

Matt89

Thread starter
Messages
1,432
Location
Virginia
Mystic; Right on...from what I recall, Saturn's website actually says that they don't specifically recommend the use of synthetic oil, but if you do use it you need to change it at the prescribed intervals. I look at my oil every week, and I've never waited until it was really "black", never mind "gritty" before changing it (based on my chosen interval). My guess is if this guy has gotten that many miles out of his vehicles, he didn't wait that long either [I dont know]
 
Messages
3,704
Location
Chattanooga, TN
No doubt that is how he got the miles, as soon as the oil started to darken or he could not see through it he changed it. Easy to get the mileage if you always have virgin oil in the crankcase.
 
Messages
238
Location
Monterey Park, CA
quote:
Originally posted by Matt89: I read this post on another forum (Car Talk BB). The thread was about how often oil should be changed:
quote:
oil change schedules and maintainence schedules are mostly bogus. They are scheduled according to averages. The only true application I have seen of most scheduled service intervals is being used by the warranty company to deny service for lack of scheduled maintinence. Oil change intervals are dependant on the amount of internal engine friction, amount of contamination from blowby gases, operating temerature, Type of lubricant used, and engine temp. I have never followed the schedule with regular oil. I have had several vehicles run fine in excess of 300,000 miles by looking at and feeling my oil on a weekly basis. Standard oil shows it's need to be changed through appearing dark and burnt and feeling thin and somewhat gritty. Synthetics are supposed to last longer and I imagine they do not show signs of breakdown as redily as regular oil does. Still if the synthetic feels gritty and or appears opaque black it means it has alot of carbon in it and should be changed. If the saturn manual says 7,500 miles and also says use synthetic only. Then you should use the synthetic reccomended. If the dealer you took it to filled it with 5w30 quakerstate than you will be needing it changed sooner more like 3,000. If the car is used and engine wear is unknown you'd be well advised to have an experienced mechanic look at your oil a few times to get an idea of what is a good interval for your vehicle. Engine wear, driving style, operating condidtions, and the type of oil used all contribute to the life of the lubricant.
Please retract everything I've ever said about the possible inaccuracies / uncertainties of lab analysis...anything has to be better than this guy's "how does it feel" test. Can you imagine going to a mechanic "Hey, can you feel my oil?" You'd either get punched out or arrested.

First time I read this, and I am doing exactly this. Everyone here should try to use real world observations of their oil, and not go by a certain recepe when it comes to extended drains. My slogan: "If its yellow let it mellow. If it's brown don't flush it down. If it's getting black on the stick either change the filter or give it the flick." Leo
 

Patman

Staff member
Messages
22,012
Location
Guelph, Ontario
quote:
My slogan: "If its yellow let it mellow. If it's brown don't flush it down. If it's getting black on the stick either change the filter or give it the flick."
This reminds me of a sign on the wall in the bathroom of one of the cottages I have stayed in a few summers ago. They didn't want people flushing their toilets too much (something about the way it was set up) so they had this sign which says "if it's yellow let it mellow, if it's brown, flush it down" [Smile]
 
Messages
238
Location
Monterey Park, CA
quote:
Originally posted by Patman:
quote:
My slogan: "If its yellow let it mellow. If it's brown don't flush it down. If it's getting black on the stick either change the filter or give it the flick."
This reminds me of a sign on the wall in the bathroom of one of the cottages I have stayed in a few summers ago. They didn't want people flushing their toilets too much (something about the way it was set up) so they had this sign which says "if it's yellow let it mellow, if it's brown, flush it down" [Smile]

When we had a water shortage here a few years back, that slogan was used everywhere. But still if I had to sit on a toilet it had to be with virgin water! Leo
 

Al

Messages
19,256
Location
Elizabethtown, Pa
It seems that every time I listen to car talk type program like "Click and Klack", "Car Talk" etc. The host always seems to be incredibly ignorant on the subject of oil. One of the shows has Castrol as the sponsor and the "Castrol Tech Rep" always makes a pitch for Syntec. What a crock.
 
Top