View Full Version : dirty oil is good for your engine!?!


nothinbuttaillights
Feb 7th, 05, 09:23 AM
This is going to get interesting, I think. Our area's premiere auto repair facility, no longer believes in, or promotes, or will do, frequent (3000-5000) mile oil changes. They are advising their customers to go up to, or beyond 15,000 miles. They only change the filters now.They say they have the latest technical data and it shows that the longer the oil stays in your engine, the better it is for it. Again, this is not a fly-by-night shop, rather one that has been here many, many years, with highly trained techs, that command VERY premium prices for their services.. So what's your opinions?

67 Convertible
Feb 7th, 05, 09:41 AM
It's hard for me to believe that they would refuse to change my oil after 3,000 miles. After all, they're in business to make money and I'm a paying customer. Aside from that, even if shown proof, I'd have my doubts. We've been told for years of the viscosity breakdown of old oil. If you get 150k-200k out of a motor by changing the oil every 3-4k miles, are they saying I can get 300k-400k by only changing it every 15-20k ?? Again, I have my doubts. I'll keep changing my daily drivers every 3k and the Camaro every 700 to 800 miles.

BPOS
Feb 7th, 05, 09:57 AM
Ditto. I'd be leery of leaving synthetic in that long, as well. Crap gets past the rings, into the oil, synthetic or regular.

georgia 69
Feb 7th, 05, 09:57 AM
Ditto on 67 convertable's post. What are you talking 30.00 dollars tops.I do my car and my wifes truck for that every 3000 miles religously.I do the work myself though.

Silver69Camaro
Feb 7th, 05, 10:17 AM
The viscosity breaks down, period. End of story. Hydrodynamic film bearings have a SPECIFIED and NECESSARY oil viscosity depending on bearing clearances.

If that bearing film, which is directly related to viscosity, is too thin, the bearing's load carrying capacity is reduced. If your bearing clearances specify SAE 30 and you use SAE 10, you get accelerated bearing wear. This is an industry accepted concept, not just car engines. Lathes, machine tools, etc all follow this.

I would ask for the data and the number of samples. If only 5-10 samples were used for the test, I'd call BS. If there are 5000 samples, then they could be on to something; the oil companies sure wouldn't want everybody to know about it.

kausboy
Feb 7th, 05, 10:46 AM
I run synthetic in my daily driver and go up to 6,000 miles on an oil change. It is primarily run on the interstate and I have been told synthetic can be run up to 10,000 miles! 6k makes me nervous but it comes out clean and I have noticed no adverse effects.

onovakind67
Feb 7th, 05, 11:07 AM
Here's a treatise on when to change oil:

http://neptune.spacebears.com/cars/stories/interval.html

nothinbuttaillights
Feb 7th, 05, 11:31 AM
The reason they won't change your oil at 3k is they are a "care care" type facility, which means, in their words, "we want to take complete care of your car, we want to have you as a life-long customer, we want to make sure what we do to your car improves it's long-term life, and we won't have you spend money foolishly". In other words, when you bring your car to them, you get their brand of service. They are not a "speedy-lube" type facility. They do have some of the leading edge techs, and the owner is really into preventive maintanence, and no throwing your money away. His facility is one of our better "accounts", so next time I see him I am going to ask him on what studies and tests he is basing his oil changing on.

onovakind67
Feb 7th, 05, 11:44 AM
And another q & a:

http://neptune.spacebears.com/opine/3koil.html

Z10Joey
Feb 7th, 05, 12:04 PM
IMO, all this 3,000 mile crap started when the "speedy lube" places were thrown up everywhere. I believe if a quality oil is used, then a 3,000 mile interval is definately premature. Of course, it depends on driving conditions etc. For normal highway driving I change my oil every 5,000 miles and my engines last with no major problems caused by excessive wear.
The Camaro gets an oil change about every 3 - 5 months because of the amout of time it sits. As far as mileage, it probably gets an oil change every 200 miles smile.gif . I Don't think it needs it, just havin fun underneath the classic! ;)

KRhat
Feb 7th, 05, 01:13 PM
I change all mine around 3000 miles, although I've heard several different opinions. Anyway, what will it hurt to change it after 3000 miles? Wouldn't that be like getting to much fresh air? (The better the oil is the quicker it'll get dirty.) Does this company rebuild engines? Kevin

Neil B
Feb 7th, 05, 01:20 PM
For what it's worth, BMW recommends oil changes every 15,000 miles or 1 year.

Bob Brissie
Feb 7th, 05, 02:03 PM
Hi, I work for a car company, and we manufacturers are constantly trying to extend the service intervals on our vehicles. Customers demand it these days, because if your product costs more to maintain than the competition,you're sunk. Todays aluminum engines dissipate heat better than the tried and true cast iron counterparts,fuel injection cuts down on the fuel contamination/breakdown of the lube, and oil now is just plain better than it was in the past, with the addition of synthetics and other additives. The bottom line is, the manufacturers provide a warranty on new cars using LONG oil change service intervals of 10k or more. This would not and could not be done if engines were seizing under warranty,since it would cost the companies millions of dollars in repairs to customer's cars. Its going to take a LONG time to have this kind thinking take root. As for me, I STILL change the oil in all of our vehicles every 3000 miles no matter what. So much for adopting the corporate culture! smile.gif graemlins/clonk.gif

ZZ430DropTop67RS
Feb 7th, 05, 02:24 PM
nothinbuttaillights, I like to see names and places.

Where is this "area"?

JimM
Feb 7th, 05, 03:15 PM
Since they started putting smart oil monitors in, I've used them. I drive my truck 30k a year, so maintenance costs are an issue with me. The monitor gives me 75-8500, and I take every mile of it.

The Camaro, on the other hand, gets 2 oil changes a year (1000-1500 miles each)

nothinbuttaillights
Feb 7th, 05, 04:01 PM
The area is Northern California, specifically the Bay area. As for the shop's name, since it is one of our "best" accounts, I will ask him before I give his name out as I do not want him deluged with phone calls or e-mails unless he's receptive. Thanks.

click
Feb 7th, 05, 05:19 PM
Dirty oil is NOT good for your engine, Im thinking someone was over exagerating to make a point.
Mobile just came out with a 15,000 mile oil and of course Amsoil has had 1yr or 25,000 mile 100% syn for 30 years now. The filtration and type of driving have alot to do with extended drain changes. Ive gone a year with all 5 of my cars and had oil analysis done on one of them and find the oil still in tolerences for continuted use, but I change once a year anyway, and oil filter changes at 6 months using 'depth' type filters, not paper cardboard cheapies. Ive used the one year drain interval for over 25 years now with excellent results.
European cars have long had 7500 and up to 12,000 mile changes in their owners manuals.
3,000 can be ok if driven in dirty conditions but for well maintained cars, a good 100% syn can do a year or more with monitoring. The additive packages and base stocks are designed to withstand alot over time without degrading.
Old school mechanics will argue till they turn blue but oil analysis proves it can be done.
BUT to each his own, you want 3000 mile changes go ahead. It makes the petro companies smile alot smile.gif

[ 02-08-2005, 06:50 AM: Message edited by: click ]

pdq67
Feb 7th, 05, 06:19 PM
I've posted this many times!

I have ran good old Walmart Tech2000 5wt30 and 10wt30 and their el-cheapo oil filters in my '87 Chevy Sprint/Suzuki Swift 3-banger corn-popper past 11,000 miles as well as in my 2000 Suzuki/Metro 3-banger when I commuted a lot! My driving was almost 100 percent clean highway and the oil still didn't look/smell all that bad!!

The key is getting your motor hot enough long enough so that it evaporates the condensation out of it's oil system whether it is water or fuel b/c it's those things plus the wear particles that make oil go bad over time and sludge up.

If I was anal about oil I would run Amsoil with a bottle of EOS or plain ROTELLA or URSA Diesel Oils b/c they still have the heavi-metal extreme pressure lubricants in them or they did the last time I looked their spec's over.

I personally can't see paying that much for synthetics when the good old Tech2000 oils have always done me fine, IMHO!!

I figure to be cost effective, I would need to run synthetics at least 30,000 miles or so AND even I am leary of doing that!

Now if I was guaranteed it would be OK to run synthetics to say, 50,000 by just changing the filter every 10,000 and topping it off with a half quart, I might consider that as being cost effective vs dino oil....

pdq67

Eric68
Feb 8th, 05, 03:46 AM
I haven't seen any real convincing tech info that going more than about 5,000 with conventional is a good idea. I know that in some instances synthetics will go a little longer, but I personally don't think the risk is worth the $30 savings.

My '02 Chevy owners manual says 5,000 miles and I put a synthetic blend in it. At 5k the oil is ready to be changed -- looks and smells a little dirty but not too bad.

The Camaro gets changed every spring and once during the summer. That works out to be about 1500 miles. I am running Mobile 1 in it with the best filter I can get -- with the bypass plugged.

Granny's 69
Feb 8th, 05, 04:32 AM
I'm ashamed to admit it but, I've gone upwards of 7,000 miles with Q-State 10W-30 synthetic blend in my daily driver truck. This isn't the norm for me but with synthetic blend, I try to not go beyond 5K miles.

onovakind67
Feb 8th, 05, 05:13 AM
From a Dodge Turbo Diesel page:

OK, the good news is that oil change intervals have been increased to 15,000 miles from the previous 7,500 so you won't have to change the oil as often.

http://www.turbodieselregister.com/hdlaunch/hdlaunch.htm

Scott Taylor
Feb 8th, 05, 06:21 AM
I use oil analysis in the generators at work. So far we are averaging an oil change every three years (about every 40 engine hours). The filters are changed annually. An oil change is a big deal for us since we have three generators that each hold 105 gallons (not quarts) of oil. Performing an oil change is an all day endeavor.

Scott.

sicsD8
Feb 8th, 05, 06:26 AM
Now how does one go about changing the filter with out draining the oil first??

[ 02-08-2005, 01:49 PM: Message edited by: sicsD8 ]

Scott Taylor
Feb 8th, 05, 06:33 AM
The filters are above the oil sump. The presence or absence of engine oil makes no difference at all.

paulm
Feb 8th, 05, 06:35 AM
No mess when I change the filter only on my cars....

sicsD8
Feb 8th, 05, 11:42 AM
What was I thinking?? :confused:

DenRS
Feb 8th, 05, 12:12 PM
Your supposed to change your oil?

z28andrs
Feb 12th, 05, 09:18 PM
Retailers are told to rotate their stock because oil degrades even on the shelf. How fast this happens is another thing. By the way, gas turbines are only replenished even though it has to withstand high temperatures; oil comes out looking like trans oil: very clean. I guess since turbines burn a quart or so every 3 hours of operation, depending on the turbine, it satisfies the need for fresh, undegraded oil. I'm just thinking out loud, but maybe the best reason not to extend too long oil changes might be particles suspended in the oil, and not oil condition itself.

click
Feb 13th, 05, 06:47 AM
Hench the reason for 'depth' type oil filter when going on long drain intervals. Pleated paper filters wont filter small enough micron particles. Good depth filters will knock down to 5 micron in dirt sizes, Paper cardboard filters are around 25 or more. With proper filtration and clean running engine, long drain interval oil analysis have shown syn oils still in remarkably good condition.
There is also an environmental plus to long drain intervals. If everyone went to just twice a year changes instead of 4, think of the oil saved, the oil not disposed of, and labor savings.
smile.gif

19HoosierDaddies67
Feb 13th, 05, 09:46 PM
I agree with Z10 from one of the earlier posts, this is all a marketing ploy to sell more oil. Most car and truck manuals say to change the oil every 5,000 to 7,500 miles, my 03' Tahoe has a light that comes on when the oil needs to be changed, as well as a place where you can check the percentage of oil life left, this is all calculated by the computer based on the type of driving you do. I routinely go 5-6 thousand miles and I have never had the light come on and tell me to change the oil, if it is good enough for the manufacturer then it is good enough for me, they have to warranty it. I use the sticker they put in my window to remind me when I last changed the oil, I usually just add 3,000 miles to it and change the oil around that time.

pdq67
Feb 14th, 05, 03:14 AM
Tell me more about this "light" b/c I can't see how it can tell you when to change oil unless it just goes by a speedometer mileage feedback through the ECU or whatever.

They sure aren't putting a "mass spec." detector on our motors are they??

I go by almost 100 percent clean highway commuter miles equals a looooong oil change interval vs running around farm fields and dry dirt roads or Rock Quarries equals a short oil change interval sorta deal is all..

pdq67

69ProTouring
Feb 14th, 05, 03:55 AM
The oil monitor on GM vehicles is called GMOLS.

GMOLS Overview (http://www.gm.com/company/gmability/environment/news_issues/news/oillife_monitor_041603.html)

wayner
Feb 14th, 05, 04:29 AM
I will continue to change my oil on my Camaro at 3000 miles.

My Camaro is a speciality vehicle, and is treated as such.

Folks that wanna go longer between oil changes are welcome to my 3000 mile oil to reuse it!!

Scott Taylor
Feb 14th, 05, 05:09 AM
I too view my Camaro as a "specialty vehicle", and as such I change the oil once a year wether it needs it or not. Oh, and in an average year I put about 400 miles on the odometer.

Scott.

onovakind67
Feb 14th, 05, 05:47 AM
Originally posted by wayner:
I will continue to change my oil on my Camaro at 3000 miles.

My Camaro is a speciality vehicle, and is treated as such.

Folks that wanna go longer between oil changes are welcome to my 3000 mile oil to reuse it!! I used to recycle the oil from my bracket race car through the tow car, and it kept that engine spotless.

Eric68
Feb 14th, 05, 06:14 AM
Originally posted by 69ProTouring:
The oil monitor on GM vehicles is called GMOLS.

GMOLS Overview (http://www.gm.com/company/gmability/environment/news_issues/news/oillife_monitor_041603.html) My Chevy has this and ironically, it always says the oil needs to be changed when I put 5,000 miles on it. It just counts down from 100% down to 0% . . . maybe it is more complicated than that but from what I've seen its just a "mileage reminder"

pdq67
Feb 14th, 05, 08:23 AM
In other words the GMOLS is just a sim. subprogram is all.

I think I will just trust my eyes, fingers AND nose!!

pdq67

PS., and I had a Buddy that had an old '49 Packard that had stuck rings in it way back when I was in highschool and didn't know about good old MMO, Rizlone and Bardahl Top-Oils.

Sucker burnt oil like a horse sucking up water at a watering trough and would run 110 mph in a heartbeat on the open road!!!

He worked for the Highway Dept one summer and burned their state truck used oil in five gallon cans!! Worked fine until he flat beat on the old Tank until he got a rod!! He loved to chase new Cads, Buicks and Olds down and pass them for the heck of it in the old Tank.... He, He!!

19HoosierDaddies67
Feb 14th, 05, 03:04 PM
If you read the article that 69ProTouring posted it explains how the GMOLS works, it is a little more complex than "just a mileage reminder" or sim subprogram whatever that is. Eric68, the fact that your light comes on at 5,000 miles all of the time might be because you drive the same way between oil changes, I drive strickly highway miles in my Tahoe and I get more miles out of my oil changes before the light is lit. I know this is a bit off subject and I think we can all agree that our Camaro's should get special attention because of the age and the lack of driving that these cars see, cars and oil for that matter were not designed to just sit....so lets all go out and drive our cars, change the oil in these as often as you want....Just for newer cars which make up the bulk of the cars on the road we don't need to change the oil as often as "Jiffy Lube" says you should because they want to sell more oil changes, fight the hype!

JimM
Feb 14th, 05, 03:16 PM
My old 96 Grand Cherokee had a "mileage reminder" light, it counted down to 7500 miles per oil change (not 3000 like Jiffy Lube would like to sell you)

The system in my Silverado seems a lot more intelligent. It certainly doesn't always count down at the same rate. I try to change at around 20% left, which is nearly always over 8000 miles. This is a 30k/yr truck, 85% highway.

Joekool1234567
Feb 14th, 05, 09:39 PM
I use the most simple and least complex way to tell when any of my cars need an oil change, I use my eyes, I pull the dipstick out of the pan and look at the oil. Dark brown or black and it gets changed, never has failed me. Just monitor the color of your oil and after awhile youll beable to tell when it is ready, I even go as far as putting a dab on my finger and then rub it to feel if it has gotten "thinner". The interval system is setup for those who dont check thier oil or those who are mechanicly incompotent and wouldnt know the differnce between a dipstick and radiator cap.

My ford truck with a 180,000+ miles usually gets an oil change every three to four months and I drive it daily, my camaro gets done about twice a year and I drive it atleast once a week.

sicsD8
Feb 15th, 05, 06:54 AM
Different brands of oils 'color' or turn dark at different rates depending on their composition. You can't accurately judge the condition and contaiminate content of any oil just by it's color.