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neon4891
neon4891 SuperDork
8/21/09 10:57 p.m.

I'm debating oil change interviles on my car. I go thrue 1QT in anywhere from 400-1000 miles. I think I might get one of the 10k mile filters (intended for syntetic, I guess) and just keep it topped off for those 10K miles...

GVX19
GVX19 New Reader
8/21/09 11:47 p.m.

Sometimes I wonder if the OEM change intervals are designed with the warranties and marketing in mind. It seems like a few years ago they got carried away with "0 maintenance for 100k" and it bit them and the intervals tightened again. Everything is crooked it seems.

+1

GVX19
GVX19 New Reader
8/21/09 11:53 p.m.
Junkyard_Dog wrote:
Nashco wrote: The factory has done lots of testing to determine the proper time to change your oil for your specific engine, car, etc. Why ignore it? Bryce
Why would a vehicle that holds 9 quarts of oil and has a tolerance of burning 1 quart every thousand miles have a 15000 mile interval? Why are more and more transmissions and differentials "fill for life" with no services at all? I'm an ASE master technician. I work for a high end manufacturer with a history of oil problems.

Sounds like you work for Porsche.

friedgreencorrado
friedgreencorrado HalfDork
8/22/09 12:03 a.m.
mad_machine wrote: that is an interesting idea. So does oil lose continuity as it ages.. or does it go up as it picks up small bits of metal?

I don't thing it's as easy as that. IMO, oil loses viscosity from repeated exposure to heat as much as it does from age or the amount of trash floating around an engine. I live in the Southeast, and down here the heat question may be more of an issue.

I've always changed the oil in my 8v Golf at 3K, but for most of her life, the commute's been about half of the one I have now. After she got hit, she sat up for about a year (with about 220K on the clock), and the valve seals dried up. After deciding to put her back together, I've been using the Valvoline/Castrol "High Mileage" products, but still changing every 3K. The last time I had to do emissions, the guy was surprised at how clean the tailpipe was. I credit that to frequent changes, and the lack of heat stress an 8v has, compared to my buddies with 16v motors-and especially to the amount of heat my VR6 Corrados have. However, with my longer commute, I'm coming up on the 3K interval a lot sooner than I'm used to..and I'm considering leaving the dino stuff in there a little bit longer just because 3K seems to arrive every two months or so. I've been checking the fill level all summer (especially after oil changes), but she's not been burning any. Only thing I have at the moment is that I can hear a valve lifter (they're hydraulic) tapping a little loud at startup. I've heard a lot of people here dismiss the "high mileage" formulas I've been using..and I wonder if I shouldn't just go back to the plain old dino stuff I'd been using since 1992.

OTOH, I just recently started using synthetic in the black Corrado. It doesn't seem to have the leaks other older VR6 powerplants do, so I figured it was worth a try. I was absolutely astonished to see the difference. Even the water temp is down during a long drive on a Southern summer afternoon. Oil temps before the synthetic were 240-270F. Afterwards, 200-230. At autocrosses, I used to have to worry about cooling the oil temps down after a run. Now, I have to worry about warming it up (I don't like to flail on an engine with less than 215F or so when it comes to racing..)

Only other thing I can say is that even though oil picks up "dirt"...if it's picking up metal shavings large enough for you to see, there's something else wrong in the inside of the engine. Bad clearances, bad bearings, bad bolt torques...

Oil is supposed to keep the metal parts from grinding each other into expensive dust. If you're seeing metal shavings, there's something wrong inside that any oil cannot cure.

friedgreencorrado
friedgreencorrado HalfDork
8/22/09 12:05 a.m.
friedgreencorrado wrote:
mad_machine wrote: that is an interesting idea. So does oil lose continuity as it ages.. or does it go up as it picks up small bits of metal?
I don't thing it's as easy as that. IMO, oil loses viscosity from repeated exposure to heat as much as it does from age or the amount of trash floating around an engine. I live in the Southeast, and down here the heat question may be *more* of an issue. I've always changed the oil in my 8v Golf at 3K, but for most of her life, the commute's been about half of the one I have now. After she got hit, she sat up for about a year (with about 220K on the clock), and the valve seals dried up. After deciding to put her back together, I've been using the Valvoline/Castrol "High Mileage" products, but still changing every 3K. The last time I had to do emissions, the guy was surprised at how clean the tailpipe was. I credit that to frequent changes, and the lack of heat stress an 8v has, compared to my buddies with 16v motors-and especially to the amount of heat my VR6 Corrados have. However, with my longer commute, I'm coming up on the 3K interval a *lot* sooner than I'm used to..and I'm considering leaving the dino stuff in there a little bit longer just because 3K seems to arrive every two months or so. I've been checking the fill level all summer (especially after oil changes), but she's not been burning any. Only thing I have at the moment is that I can hear a valve lifter (they're hydraulic) tapping a little loud at startup. I've heard a lot of people here dismiss the "high mileage" formulas I've been using..and I wonder if I shouldn't just go back to the plain old dino stuff I'd been using since 1992. OTOH, I just recently started using synthetic in the black Corrado. It doesn't seem to have the leaks other older VR6 powerplants do, so I figured it was worth a try. I was absolutely astonished to see the difference. Even the water temp is down during a long drive on a Southern summer afternoon. Oil temps before the synthetic were 240-270F. Afterwards, 200-230. At autocrosses, I used to have to worry about cooling the oil temps down after a run. Now, I have to worry about warming it up (I don't like to flail on an engine with less than 215F or so when it comes to racing..) Only other thing I can say is that even though oil picks up "dirt"...if it's picking up metal shavings large enough for you to see, there's something else wrong in the inside of the engine. Bad clearances, bad bearings, bad bolt torques... Oil is supposed to keep the metal parts from grinding each other into expensive dust. If you're seeing metal shavings, there's something wrong inside that *any* oil cannot cure.

EDIT: I neglected to mention that the valve seals in my 8v Golf were replaced after drying out. That's probably why the thing isn't consuming any oil at the moment.

Brust
Brust Reader
8/22/09 9:55 a.m.

Problem is, you can't see metal shavings until you drain the oil. With something like a "chip light" you'd get an indicator telling you there were metal shavings.

DirtyBird222
DirtyBird222 Dork
8/22/09 11:09 a.m.

How about this one? Change oil, check at 1k, 2k, and 3k after change, if dirty replace? That's usually how I go abouts it. But if my oil is dumping into my cats, then E36 M3, I have a bigger problem at hand. I recently worked on a car that had 120k miles on it, the guy only changed the oil every 30k miles. The old oil had started to coagulate/crust onto parts of the valvetrain causing catastrophic failure. The guy said it was bullsh*t he had to change oil every 3-5k miles and that the oil companies and car companies were all scheming us to make more money. Needless to say he didn't pay to fix his car either.

friedgreencorrado
friedgreencorrado SuperDork
7/9/10 4:05 a.m.

PinkBagGirl wrote:

snip!

pete240z
pete240z Dork
7/9/10 7:55 a.m.

my brother has "free" oil changes in his new Audi. He claims he has to change the oil every 10,000 miles.

However at 5,000 miles the "check oil" light comes on and he goes to the dealer and they add a quart or two.

that sounds crazy to me.

triumph5
triumph5 New Reader
7/9/10 8:05 a.m.

In reply to GVX19:

Sounds more like BMW.

triumph5
triumph5 Reader
7/9/10 8:11 a.m.

In reply to DirtyBird222:

I've heard ot that happening if the oil is changed when the engine is cold, and in a very humid area, or if the head gsket had a slight coolant leak, causing the coagulation on the valve train. I remember Smokey yunick writing about this happening back in the seventies.

WilberM3
WilberM3 Reader
7/9/10 9:36 a.m.

having seen the problems BMW's 15000 mile oil change interval causes first hand, i'll stick to a little more frequent thanks. oil filter elements crumble apart, massive sludging, and ultimately if left unchecked secondary problems with the oil seperation valve sucking 6 quarts of oil into the intake hydrolocking the engine....

iceracer
iceracer Dork
7/9/10 9:40 a.m.

A comment on the ASE thing. Back in the days when mechanics were rated A.B, C and maybe D. You had to earn that rating, not take a test. When ASE first started out , my dealer wanted me to take the test. I said , if you will pay for it, i will take it. He never did. I looked over one of the tests, wasn't difficult at all.

1988RedT2
1988RedT2 Reader
7/9/10 10:18 a.m.

I believe the mfrs. oil change interval recommendation is a compromise seeking to accomplish all of the following incompatible objectives to the greatest degree possible:

1) killing the engine in order to sell the customer a new car. 2) making the car last long enough to get out of the warranty period, and not look bad relative to the competition. 3) "reduce our dependence on foreign oil" at the insistence of govt.

I find it interesting that the mfr. will recommend, let's say 7500 miles, and the dealership will give you free oil changes every 3000 miles. Needless to say, I'm letting the dealer change my oil for free every 3000 miles.

Regardless, I'll change my conventional oil every 3000 miles, and my synthetic between 5000 and 7500. It's highly unlikely that any "astonishing new discoveries" will do anything to change that.

PeterAK
PeterAK Dork
7/13/10 7:45 a.m.

Big canoe.

alfadriver
alfadriver Dork
7/13/10 9:09 a.m.

Some of you conspirists are funny- that OEM's tell you to change oil less frequently so that the car wears out faster.. that's hilarious. Come on- you can't be serious- we are all measured by how long cars last, so if they all fail reliably at 150k miles, vs. another that lasts +300k you would be crucified.

US cars are required to meet emissions to 120k miles, Clean state cars are required to meet emissions to 150k miles. For that to happen, you need to deposit little enough phosphorus on the catalysts to be roughly equivallent to 15k miles per quart burnt (+- some, depending on the standard you are trying to meet).

Basically, the oil change requirement is a customer want, that started in the European market, for the vehicle to require less maintenence. Since MOST of a vehicle maintenence is oil changes, thus the move to increase the span of the oil changes to beyond 10k miles (or just over 1.5 times, average, per year). Engines last just fine out at that interval- even super thin oils like 5w-20 (which is the current standard for most engines).

For the mechanics that like to change oil at 3k miles, of course you do- you'll get paid 3x as often as you should for a simple change. 5k = twice as often as you should. Dealers try to do that to, but you have to understand that dealers are NOT the OEM's- they just sell and service the vehicles.

As for those of you who wait to warm up your car, as well- that, too, is a waste. Mainly of gas and your time. Driving warms up the car faster, and generally leads to lower overall emissions (and I've done the testing to know that). Just remember, sitting still = 0 mpg.

The car is designed to be able to drive away immediately, and the emissions test only has a 15 sec neutral idle, 5 seconds in drive (or 20 sec neutral for manuals), and then the car is driven.

If you want to wait a min or two, and insist on changing oil at 3k miles- that's fine- it's your money. Just be aware that you are saving nothing in the engine.

Brett_Murphy
Brett_Murphy GRM+ Memberand New Reader
7/13/10 2:14 p.m.

In reply to mad_machine:

It's my understanding that heat and chemical contamination kill oil and metal shards kill your engine. =) Ever have an older car flood out and then smell your oil? It'll smell like gasoline, and I don't trust it when it smells like that.

I could be imagining it, but I'd swear that in one of the manuals for my car, they suggest an oil change before and after any Track Day or Spirited Driving event. I was shocked as heck to see that.

96DXCivic
96DXCivic Dork
7/13/10 2:26 p.m.

I still change my oil every 3k miles because well that is what my grandpa taught me and now it is a habit.

93celicaGT2
93celicaGT2 SuperDork
7/13/10 2:46 p.m.
Brett_Murphy wrote: In reply to mad_machine: It's my understanding that heat and chemical contamination kill oil and metal shards kill your engine. =) Ever have an older car flood out and then smell your oil? It'll smell like gasoline, and I don't trust it when it smells like that. I could be imagining it, but I'd swear that in one of the manuals for my car, they suggest an oil change before and after any Track Day or Spirited Driving event. I was shocked as heck to see that.

My oil smells like gasoline within 10 miles after changing it. I just ignore it.

wbjones
wbjones Dork
7/13/10 6:37 p.m.

I change before and after each track session... may be wasting money, but I bet it doesn't hurt the engine.... there are usually several a-x between each track day... ( + I change the brake fluid before each track day )

friedgreencorrado
friedgreencorrado SuperDork
7/13/10 9:14 p.m.
alfadriver wrote: Some of you conspirists are funny- that OEM's tell you to change oil less frequently so that the car wears out faster.. that's hilarious. Come on- you can't be serious- we are all measured by how long cars last, so if they all fail reliably at 150k miles, vs. another that lasts +300k you would be crucified. US cars are required to meet emissions to 120k miles, Clean state cars are required to meet emissions to 150k miles. For that to happen, you need to deposit little enough phosphorus on the catalysts to be roughly equivallent to 15k miles per quart burnt (+- some, depending on the standard you are trying to meet). Basically, the oil change requirement is a customer want, that started in the European market, for the vehicle to require less maintenence. Since MOST of a vehicle maintenence is oil changes, thus the move to increase the span of the oil changes to beyond 10k miles (or just over 1.5 times, average, per year). Engines last just fine out at that interval- even super thin oils like 5w-20 (which is the current standard for most engines). For the mechanics that like to change oil at 3k miles, of course you do- you'll get paid 3x as often as you should for a simple change. 5k = twice as often as you should. Dealers try to do that to, but you have to understand that dealers are NOT the OEM's- they just sell and service the vehicles. As for those of you who wait to warm up your car, as well- that, too, is a waste. Mainly of gas and your time. Driving warms up the car faster, and generally leads to lower overall emissions (and I've done the testing to know that). Just remember, sitting still = 0 mpg. The car is designed to be able to drive away immediately, and the emissions test only has a 15 sec neutral idle, 5 seconds in drive (or 20 sec neutral for manuals), and then the car is driven. If you want to wait a min or two, and insist on changing oil at 3k miles- that's fine- it's your money. Just be aware that you are saving nothing in the engine.

Agree on the conspiracy theorists. Still gonna waste my money every 3K on dino juice and about twice that on the synthetics, tho. Cheaper than my insurance bill..or even an "extended warranty". But I agree again on the "warmup". Motoring slowly until the temp comes up also warms up the gearbox, etc. IMO. I usually have to park on the bottom floor of our underground parking garage at work, it kinda gives me an excuse to just play "no wake zone" long enough to get the temps up.

Knurled
Knurled GRM+ Memberand Reader
7/13/10 10:08 p.m.
bludroptop wrote: From a Yahoo link about unnecessary auto repairs: "That oil change? Turns out every 5,000 miles is often enough. New oil has chemicals that eat away the catalytic converter, says Donny Seyfer, a Colorado-based certified master technician, and changing oil too often can damage that pricey part."

Actually, modern oils have a lot less phosphate (ZDDP) in them, specifically for catalyst life. You don't want to use SM-rated oil in an older engine because of this.

If additives in fresh oil are bad for the converter, and these additives deplete over time, this only proves that you WANT to change the oil more frequently.

Interesting fact: Ford does recommend a 5k oil change. Motorcraft oil is also a partial synthetic.

Another interesting fact: I bought some oil at $1.69/quart today. When I got home, I noticed that it is API SB. Not SM or SL or even SJ, but SB. Well, my car eats a quart every 200 miles anyway, probably not going to hurt much.

Knurled
Knurled GRM+ Memberand Reader
7/13/10 10:19 p.m.
alfadriver wrote: For the mechanics that like to change oil at 3k miles, of course you do- you'll get paid 3x as often as you should for a simple change. 5k = twice as often as you should.

If we were concerned about making money, we'd do 15k oil changes and free 3k safety checks. $x per quart plus $y for a filter plus 1/2 hour minimum at Z labor rate adds up to a LOT more than $27.

Oil changes are always done at a loss, why would we want to lose money faster?

My daily driver (the 200mi/quart one) gets oil changes at 3k. Even though it gets a depressingly steady diet of fresh oil, it's not ALL of the oil that gets burnt. My lifters let me know that they are unhappy with the oil after 1500 miles. They STFU and GBTW with a full load of new oil. And, that first burnt-off quart can take as long as 1000mi to happen, oil consumption steadily rises as a function of mileage since oil change and resets with new oil.

My other car gets 20W50 Agip synthetic racing oil. I change it when my oil pressure on the highway drops from 55psi to 45psi, at which point the oil will be a quart overfull from all of the raw fuel in it. This takes about 2,000mi. Silly weird rotaries.

Knurled
Knurled GRM+ Memberand Reader
7/13/10 10:27 p.m.
friedgreencorrado wrote: Agree on the conspiracy theorists. Still gonna waste my money every 3K on dino juice and about twice that on the synthetics, tho. Cheaper than my insurance bill..or even an "extended warranty". But I agree again on the "warmup". Motoring slowly until the temp comes up also warms up the gearbox, etc. IMO. I usually have to park on the bottom floor of our underground parking garage at work, it kinda gives me an excuse to just play "no wake zone" long enough to get the temps up.

Pet peeve: Comparing "dino juice" and "synthetic". Synthetic is petroleum based too, some of it from crude but usually natural gas. The difference is that it isn't refined from, but rather is assembled to, so you can dictate exactly what is in it. Requires less additives in it that way.

I firmly believe in letting the vehicle warm up in the winter, because while it is not the best thing for the engine, it's even worse for the engine when the car gets totalled out because you hit a parked car or a tree because you can't see where you're going because there's no heat and the windshield ices over when you start moving in the damp air.

Barring severe acts of mechanical negligence (like, say, not changing your oil very often), engines by FAR will outlast the car, anyway. At least 'round here. By the time the engine has 150k on it, there isn't any car left around it. Worrying about engine longevity seems a little pointless, no? That'd be like popping the hood every night so the little popper spring doesn't spend all of its life in compression...

I note with great interest and approval that many new vehicles have resistor grids over the heater core for instant heat.

pigeon
pigeon HalfDork
7/13/10 11:10 p.m.
WilberM3 wrote: having seen the problems BMW's 15000 mile oil change interval causes first hand, i'll stick to a little more frequent thanks. oil filter elements crumble apart, massive sludging, and ultimately if left unchecked secondary problems with the oil seperation valve sucking 6 quarts of oil into the intake hydrolocking the engine....

I agree that the 15k interval on BMWs is a bit long. I don't believe the oil separation valve issues the M52 motors have is related to long change intervals. I bought my old '99 328i at 100k miles and it had had oil changes by the book. I cut the interval in half, still using full synthetics. When I pulled the valve cover at 135k or so to change the leaky gasket there was no sludge or any oil issue to be seen. I ran that car HARD all the time too. Motor ran like a top and burned no oil between changes when I sold it at 168k miles.

I did an oil analysis on my 750Li a couple months ago and posted the results here: http://grassrootsmotorsports.com/forum/grm/oil-analysis/21927/page1/ At 15k my oil was totally shot from a TBN standpoint but otherwise it was fine, according to Blackstone Labs anyway. I'll run 12k on this change and probably get the UOA done again.

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