I remember reading the article. One problem I have with this study is that the NY cabs run constantly so that the engine is always fully warmed up. With today’s fuel injected engines as opposed to yesterday’s carbureted engine, there isn’t as much raw gasoline dumped into the crankcase. This may be the difference between the study cited by Tom McCahill and Consumer Reports. I think that the person who starts his car, drives 2 miles to work, shuts it off and then reverses this run at the end of the workday is probably operating his car under more severe conditions than the NY cab fleet.
Tom McCahill had some interesting opinions about oil which are not valid today. He thought multiviscosity oil was “sucker juice”. He stated that 10W-30 oil was “a lousy number 10 and a lousy number 30”. He didn’t like detergent oils. “I like soap in my bathtub but not in my crankcase”. He always used one weight higher than specified, gave adequate time for warm-up and claimed to never had an oil burner in 100,000 miles of service.
Go by your oil change indicator. It’s simulation for oil deterioration was created with input from GM engine designers and testers. Your car company, no matter the brand has customer satisfaction including long engine life in mind to the best of their ability and intents in a competitive environment.
Be sure to use the correct oil and in your case, a synthetic with the GM advised designation on the bottle.
That said, I change ours when the indicator gets down to around 10% or a little higher. There should also be an oil change time maximum in your owner’s manual, 1 year.
No offense gang, but properly used, the computer is accurate.
The manual specifies the oil, those bunches of letters, and the computer presumes you are using it and…will accurately determine the service life based on algorithm calculations and the time the vehicle is driven.
The HHR uses 0-W30 or 5-W30 oil. Mobil 1 is installed at the factory and is specified.
Mobil 1 is no longer advertised as a 30,000 mile oil but that is for legal reasons.
So, lets keep in for only half that time…screw it…how about 1/4th…7,500 miles.
If Mobil 1 can go 7,500 miles between changes, why follow grandpa’s advise, based on ancient technology, and throw away perfectly good oil? Oil is not that cheap. And tossed out oil ends up somewhere…
All it needs is filtration. And there are filters designed for the job.
Then there is the question:
Do you really believe the Mechanical Engineers, and Chemical Engineers involved in the making of your cars are so stupid as to not know what hey are doing?
And if they are, what does that say about who buys their product?
While it is possible for the ‘Quickie’ shops to do the wrong thing, like install the wrong viscosity, forget to tighten plugs and the like.
Good reason to go to the ‘Cah Tawk’ Find a Pretty-Darn Good Mechanic link.
The real answer will depend on your driving habits and may lie between the two or even underneath the lower one.
Normal, short hop/stop and go driving should mean a 3-4 months/3000-3500 mile interval.
A lot of highway driving can mean 5-6 months/5000-6000 mile intervals.
If it’s like one of my sisters-in-law, then about every 2-3 months/2000 miles would be proper. In her case most of her driving involves trips of less than 2 miles and this means the thermostat in the engine never gets warm enough to open. This type of driving is the roughest on an automobile engine and is generally the cause of engine sludging problems which you may have heard about.
(And to head off any wondering about why my sister-in-law even owns a car in the first place it’s because a physical problem does not allow her to walk or bike to work and there is no bus service in her area.)
I have two GMs w/oil life monitors. Since I use Mobil 1 and a Napa Gold Filter on both vehicles, I go by the oil life monitor (usually tells me to change at about 6000 miles or so. These oil changes occur at about every 5 to 6 months, so I’m changing oil in either car within 6 months.
If I were using conventional oil, or getting it changed at a discount oil place, I’d go 3000 miles and change regardless of what the oil life monitor told me.
Your computer is programmed to read your exact driving parameters, driving time, cycles, time to warm up etc so an exact # of miles comes about. The # every 5k miles is very arbitrary to cover all cases not your exact one.
If it were me I would follow indicator not to exceed optimally 6months or 1 year at most. Remember they do typically account for calender time.
Make sure you use proper spec’ed oil which is likely normal stuff in your vehicle.
1: For all those who replace their oil more frequently than specified in the owner’s manual, how do you know your engine is lasting longer because of it? And define “longer”, ie 300K miles vs what?. (Leave out defective engines with sludge problems.)
2: Engine designers determine the driving patterns that accelerate oil contamination. They use an engine’s sensors to collect the data on how a car is driven. They use their calculations on that data to report to you, when an oil change is needed - ie the oil change indicator.
For those who don’t believe in the oil change indicators, what is it that you know that the engine designers don’t?
“Regular” oil changes should be complemented with regular oil analysis (once or twice a year). The analysed contaminants can tell you if some component is nearing failure. This way, you can be forewarned before a failure and take appropriate measures. This could help preserve the treasury.
The reason I say don’t put all your faith into an oil change indicator is because the automotive engineers don’t, and can’t, figure in environmental conditions that are present and which vary all of the time.
Here in OK it’s generally very humid and in the fall/spring there are many cool, very damp days. Since heat attracts moisture this means the engine can sweat just like a window on a house and repeated short trips is not going to burn that moisture off.
Besides, I don’t consider automotive engineers the final authority. These are the same guys who recommend no trans fluid changes, no fuel filter changes, 15k mile oil changes, recommendations to delay valve lash inspections, etc., etc., and who also came up with the idea to allow a plastic govenor drive gear to propel a steel govenor driven gear in an automatic transmission.
Not being an engineer, even I would have raised my hand at the round table discussion and questioned the logic of that one rather than allow the car owners to find out after the warranty ran out that a large repair bill was going to be on their dime.
Automotive engineering history is cluttered with design flaws and utter stupidity that makes one wonder what in the xxxx they were thinking.
Joe, engineers do not make the final decisons on recommeded oil change intervals. If they did you would get recommendations like those of OK. The marketing people decide what type of maintenance interval “sells”, and the advertising takes it from there. “Low Maintenance” is all in fashion now but if you ask a good mechanic, most of it is smoke and mirrors.
In another post we talked about the engine having to make it beyond the warranty period (which often coincides with the first owner trading it)with very few failures. That’s possible with a long drain interval, except with such sludging engines as Volkswagen and Toyota produced. Toyota then cut the interval from 7500 back to 5000. But actual engine life is about THREE TIMES the warranty period. Car manufacturers basically cater only to the first owner.
I have definite, controlled proof how long an engine will last with litle wear. Our family owned a 1984 Impala V8 for 20 years. The car was used in all kinds of weather (-40 to +100) and the oil was changed religiously at 3000 miles or so, using good dino oil.
When we finally sold the car it had over 300,000 miles on it and the compression was 95% of new, it USED NO OIL, and the engine and transmission had a lot of life left in it. This was 20 years of mixed driving, not New York taxi service which is actually easy on oil, as pointed out.
The kid who bought the car for $750 is still driving it, not blowing blue smoke and even takes it on long trips to visit his parents 800 miles away.
As others have said, oil is cheap but engines are expensive.
OK, I’m an engineer, but the stuff in the car manuals gets watered down by the marketing department, see my above post. If you buy a Caterpillar bulldozer, or a heavy duty Class 8 truck you get more factual, and unedited maintenance recommendations.
Construction and trucking companies analyze oil on a regular basis to 1) optimize the drain intervals without incurring excessive oil deterioration and 2)identify impending failure from abnormal oil chemistry or deposits.
When Ford went “Duratec” the maintenance intervals were pure marketing; the engine coolant often outlasted the radiators! But most of these made it throught the warranty period with minimal owner outlay for maintenance. I always feel sorry for the next owner who will be picking up the pieces.
I live in a similar climate as you do, only 15-20 degrees colder. Frequent oil changes to reflect those climate and driving conditions allow engines to last a long time.
I've typically done the 3000 mile oil changes, but the oil indicator's just fine. Triedag sums it up -- it measures actual driving, so if you do winter driving, or short drives where the engine doesn't warm up (so the oil gets moisture building up in it over time), or severe driving (so the oil "cooks" over time), it'll recommend short intervals. If not, the oil is fine and it recommends longer intervals. As the car gets older (like 5-10 years from now) I would check the oil *level* on the dipstick periodically, so you don't have it start burning oil and run out of oil before you're due for a change. But I'd go by the change indicator, it's safe.
True; McCahill’s world was light years away from today’s environment. We now have about 25% of the oil volume in additives for every possible evil. Viscosity improvers, which Tom distrusted and loathed, are a fact of life and very reliable in their performance. In Tom’s time oil had very few additives to fight wear, corrosion, acidification, etc.
Getting the lead out of the gas, electronic fuel injection, and computer finetuning of the fuel/air mixture makes for very little oil being washed off the cylinder walls under normal driving.
It’ s a different world, but short trips in cold weather without the engine heating up is still very hard on the engine, and short drain intervals are still recommended.
Consumer Reports tested oil in NY cabs, who often go to up to 10,000 miles between oil changes because they never cool down. So the difference between 3000 miles and 7500 miles is negligble. However, Aunt Minnie in Northern Minnesota who starts up her car (parked outside ) every morning to drive 1 mile to the 7-11 to get a paper is still murdering her engine. This type of driving requires 1000-1500 mile intervals!!!
I even wonder if Tom McCahill’s statements about detergent oil were even true back in the early 1960’s when Tom McCahill printed them. I had a 1954 Buick at the time and it had hydraulic lifters so that detergent oil was a necessity.
There were many cars that did not have hydraulic lifters and did not have an oil filter. I suppose non-detergent oil was perfectly satifactory for these engines. My dad had a 1949 Dodge and oil consumption shot up immensely when he switched to detergent oil. I’ve wondered if McCahill heard about cases like this and thus made the statement.
My opinion is that if you aren’t on the fringes of normal usage, for example 2 mile trips every other day for years on end, or high speed runs through boiling hot desert conditions for hours on end, then the oil life indicator should be your guide. That’s what I use. It turns out, my oil life indicator seems to want me to change my oil about every 6 months or 5000 miles (give or take a little) which is pretty close to what I used to do anyway.
For normal usage, the oil life indicator is fine. The oil change places like to sell oil changes, thus the 3 month or 3000 mile sticker, it’s bogus.
Agree, for average mileage and driving conditions, the oil life indicator will work OK. It’s a habit of service centers to push as many oil chages as they can scare you into! Those dumb stickers on your windshield are actually believed by many people.
My neighbor is a retired gentleman. His 2004 Focus has just had its THIRD!! oil change. He drives very little, but Ford still pesters him to bring the car in every 3 months. He trades cars every 6 years and gives his “old” car to his daughter, who drives a lot! He will be giving her an out-of-warranty car with 15,000 miles on it and a perfect body.