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  #21  
Old 19 December 2007, 01:18 PM
Troberg Troberg is offline
 
 
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Question for Europeans- what about the oil filter? I have heard that one option is to rarely or never change the oil, just add a quart when needed, but that one still needs to change the filter.
When I have a newish car (still on warranty), I change it when I change oil. On an old clunker, I change it when the oil pressure warning light tells me it's about effing time to change it. As long as some oil can flow through the filter, it will work.

A modern engine is made with higher precision and better alloys, modern oil is much better than the oil used 20 years ago. Cooling is more efficient (although modern engines run hotter for environmental reasons, hotspots is less likely to occur). It's a better construction due to increaed understanding and the use of sofisticated computers in the construction. The problems have been sorted out. I mean, when was the last time you had an actual mechanical failure in the engine proper (by that, I exclude such things as water pumps and radiator)? A modern engine is extremely reliable, even if maintenance is neglected, and will outlive the life expectancy of the rest of the vehicle.

You know those amazing fuel additives they show on TV-Shop? They drain out the oil and the engine continues to run. Well, here's the trick. An engine will run for quite a while when idling without oil, with or without expensive additives. There is still enough oil left in the system to keep it lubricated enough to stop it from seizing.

Oil is good for the engine, but the engine is picky about it. It will happily use pitch black oil that has been running for several years. Look at the Soviet aviation engine family Vedeneyev M14, which is probably the aviation engine produced in the largest numbers and which is also used to power generators and other stuff. When powering generators, the maintenance schedule say that maintenance (and that include the oil changes) should be done every 20 000 hours running time (2250 hours for aviation use, with minor maintenance every 500 hours). Now, that's pretty impressive, and that's a performance engine.
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  #22  
Old 19 December 2007, 01:24 PM
bugeye
 
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I worked in a large city automotive maintenance shop (over 1600 units) for five years and we tested used oil regularly on vehicles chosen at random. These included heavy road/landfill/sanitation units and regular trucks and automobiles from the Police and motor pool.

We found that allowed us to run units 6000 to 8000 miles depending on the use without having any metal shavings showing up in the used oil. Police pursuit units needed to be changed more often than the City Hall motor pool cars. It was a good way to cut expenses since we had been changing the oil every 3000 miles. We always changed the filters as long as we were in there.

For recycling the oil, most WalMarts (in Oklahoma anyway) with an automotive shop have a storage tank where you can empty your used oil for free. We can leave up to two gallons a month. Otherwise, many national chain auto parts shops will also take the used oil.
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  #23  
Old 19 December 2007, 02:09 PM
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DrRocket DrRocket is offline
 
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Crankcase oil serves multiple functions in a car. Primary, of course, is lubrication. Anther function is collecting and holding in suspension contamination from the combustion processes. Not only the solids that the filter will trap (For the most part) but also acids and other chemical byproducts. A third function nobody ever really thinks about is cooling. It carries heat away from the bearings as it travels through the lubrication system and sheds it when returned to the oil pan. While it would be possible to get the solids out of the oil, there's no possible way to get rid of the chemical contaminants without a lot of expensive reclamation equipment and an EPA permit, and those chemical contaminants are as bad for your engine as any solids. Plus, as oil is used, the additives in it break down, as does the oil itself.

The idea that you can go for five years without changing oil seems nice, and probably appeals to people who'd like to skip car maintenance. (My brother, for instance, who uses the "I-key" system. "I turn the key. If it doesn't start, it's time for maintenance.") You'll NEVER catch me waiting that long.

Ever.

5,000-6,000 miles is the interval I use. A lot of new cars have "indicators" that will tell you your oil should be changed, but that's based on miles driven, not any "sensor" that detects dirty oil. On my Buick that mileage interval can be set by the owner. As noted, I have mine set at 5,000, them I begin to think about it. The manufacturers will tell you you can go a lot farther not necessarily because they think it's a good idea, but because they want to appeal to the car maintenance challenged amongst us, like my brother.
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Originally Posted by Troberg View Post
....It will happily use pitch black oil that has been running for several years.....
Troberg, remind me to NEVER buy a car from you!!
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  #24  
Old 19 December 2007, 04:02 PM
Insensible Crier Insensible Crier is offline
 
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Originally Posted by Troberg View Post
When I have a newish car (still on warranty), I change it when I change oil. On an old clunker, I change it when the oil pressure warning light tells me it's about effing time to change it. As long as some oil can flow through the filter, it will work.
The oil pressure light is not there to tell you when to change your filter. I could have a brand new filter and the oil pressure light can come on if there's a leak. And if the filter is so gunked up that it stops the flow of oil then you are just asking for engine problems.

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Originally Posted by Troberg View Post
A modern engine is made with higher precision and better alloys, modern oil is much better than the oil used 20 years ago. Cooling is more efficient (although modern engines run hotter for environmental reasons, hotspots is less likely to occur). It's a better construction due to increaed understanding and the use of sofisticated computers in the construction. The problems have been sorted out. I mean, when was the last time you had an actual mechanical failure in the engine proper (by that, I exclude such things as water pumps and radiator)? A modern engine is extremely reliable, even if maintenance is neglected, and will outlive the life expectancy of the rest of the vehicle.
A bunch of times. The last time was a 93 Corsica that my friend had which died because he didn't see the oil pressure light come on while doing 80 mph on the interstate. Engine needed to be completely rebuilt.

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Troberg, remind me to NEVER buy a car from you!!
Same here.
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  #25  
Old 19 December 2007, 04:17 PM
jimmy101_again jimmy101_again is offline
 
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Like Dr Dave said, you need to take into account how often the filter is changed as well.

It used to be that the filter was supposed to be replaced every other oil change. Not sure what car manufacturers recomend these days.

The filter is probably more importan than the oil. The filter is the thing that removes particulates from the oil and it is the particulates that do the most damage to an engine.

Most oil filters are designed with a bypass. When they clog up the oil flows around the filter instead of through it. I would think that after a couple years the typical filter is no longer doing much.
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  #26  
Old 19 December 2007, 04:18 PM
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Originally Posted by kitap View Post
If I remember correctly Click and Clack say that 3 months/3,000 is for older cars or if you do a lot of stop and go driving. If you do lots of highway driving 5,000 is fine.
I also remember them saying that's partly due to the face that the quality of the oil we use now is higher than it used to be.

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Originally Posted by Insensible Crier View Post
It also depends on the type of oil you use. Pure synthetic oil (which is standard for all BMWs or so my coworker says) says every 12,000 miles. Most of us use the regular stuff which is every 3000-5000 miles.
This actually might be the source of the difference in the opinions between many of us and Troberg and his coworkers. I could be wrong, but I think synthetic oil is much more commonly used in Europe than it is here. Maybe Trobeg and his coworkers are assuming synthetic oil while the American posters are assuming regular petroleum oil.

It takes me about a year to put 5000 miles on my car, so I just change my oil once a year. Although this year I did notice that it was developing a clicky-clacky valve type noise which went away after the last oil change.
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  #27  
Old 19 December 2007, 04:21 PM
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1958Fury 1958Fury is offline
 
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Originally Posted by Lainie View Post
Y'all are making me feel much better about my own car maintenance record.
I was just thinking the same thing.
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  #28  
Old 19 December 2007, 04:32 PM
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star_splinter star_splinter is offline
 
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I use a synthetic blend and change every 3000 miles, without fail (that works out to about every three months). Then again, my car is already 16 years old and I'd like it to go for another 10+.

I've always read that regular oil changes are the most effective way to prolong the life of your engine. For the people who do oil changes by time rather than mileage--how many miles do you put on your car in an average year?
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  #29  
Old 19 December 2007, 04:38 PM
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I'm not sure about the three months thing, because I don't think oil breaks down just by sitting around. At least not that quickly. Otherwise wouldn't oil need a 'use by' date on it?

As for miles, I think it depends on the car as much as how it is used. With every Totyota or Honda I've owned (all four of them), I've changed the oil at 5000 miles or more. It is almost always still pretty clean looing at that. With the Saturn I owned, I blew an engine at 60,000 miles and the people of Saturn told me this was because I sometimes waited until 4000 miles to change my oil.
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  #30  
Old 19 December 2007, 04:39 PM
Shadowduck
 
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Originally Posted by star_splinter View Post
For the people who do oil changes by time rather than mileage--how many miles do you put on your car in an average year?
DW's car gets the oil changed annually as it never gets close to the 20,000 mile limit in a year - it's only used for shopping trips, days out and ferrying kids around so it's only done 30,000 miles in five years.

Not that I'd necessarily change the oil more if the mileage was higher...
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  #31  
Old 19 December 2007, 04:52 PM
Troberg Troberg is offline
 
 
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The oil pressure light is not there to tell you when to change your filter. I could have a brand new filter and the oil pressure light can come on if there's a leak. And if the filter is so gunked up that it stops the flow of oil then you are just asking for engine problems.
If it's that gunked up, oil pressure will drop and the light will warn me. It has yet to happen, though.

Quote:
A bunch of times. The last time was a 93 Corsica that my friend had which died because he didn't see the oil pressure light come on while doing 80 mph on the interstate. Engine needed to be completely rebuilt.
Yep, an engine working hard will seize if oil pressure is lost. That has nothing to do with the quality of the oil.

Quote:
Troberg, remind me to NEVER buy a car from you!!
I only treat the clunkers that bad, the good cars get new quality oil every 1-2 years.

Quote:
Most oil filters are designed with a bypass. When they clog up the oil flows around the filter instead of through it. I would think that after a couple years the typical filter is no longer doing much.
I didn't know that. I've never bothered to open up a used filter.

Quote:
This actually might be the source of the difference in the opinions between many of us and Troberg and his coworkers. I could be wrong, but I think synthetic oil is much more commonly used in Europe than it is here. Maybe Trobeg and his coworkers are assuming synthetic oil while the American posters are assuming regular petroleum oil.
Some, but most, including me, use good quality mineral oil. I always use Quaker State. If it's good enough for helicopters, it's good enough for my car.

Quote:
Although this year I did notice that it was developing a clicky-clacky valve type noise which went away after the last oil change.
If it was the valves, it was not fixed by the new oil.

Quote:
I've always read that regular oil changes are the most effective way to prolong the life of your engine.
How long do you use a car nowadays? 20 years? 30? Sweden has a very old car park, partially due to the popularity of '50ies American cars, but also the Swedish tendency to not throw anything away, so we keep the old cars as spare cars or second/third/fourth cars. Yet, it's not the engines dying that kills the cars. Almost without exception, it's rust, bad radiators, bad fuel tanks/fuel pumps and bad electronics. Abuse your engine, it will still outlive the car.

By the way, there is another reason for me to change oil. If they complain about emission values during the annual checkups, I change oil.
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  #32  
Old 19 December 2007, 05:02 PM
Shadowduck
 
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Quote:
Originally Posted by Troberg View Post
If it's that gunked up, oil pressure will drop and the light will warn me. It has yet to happen, though.
As already mentioned, oil filters have a pressure activated bypass valve. If the filter is completely clogged the bypass will open, so the oil pressure light will not come on. Not because of your filter at any rate!
Quote:
Originally Posted by Troberg View Post
If it was the valves, it was not fixed by the new oil.
Hydraulic tappets can become noisy if the oil level is low or if the oil is old and has lost viscosity. So new oil (or sometimes a top up) can fix top end noise.
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  #33  
Old 19 December 2007, 06:10 PM
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My brother was on a submarine for awhile. He said they never "changed" the oil, they ran the old oil through a centrifuge to clean the dirt out of it. After a trip through that baby the oil came out golden just like new. He claims that unless some chemical reaction causes the oil to lose it's viscosity it will last indefinately. But keep it clean because the oil not only lubricates, it cleans the inside of the engine.

I use synthetic and change it about once a year.
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  #34  
Old 19 December 2007, 06:16 PM
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I have been told that you change your oil every 3,000 miles. If you change the filter too, add 3,000 miles. If you use synthetic, add another 3,000. I don't think I'd ever go more than about 5,000 miles though.
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  #35  
Old 19 December 2007, 06:41 PM
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DrRocket DrRocket is offline
 
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Since several posters here have mentioned Click and Clack, The Tappet Brothers, I thought I'd post a link to their recommendations:From the horse's mouth!

And yes, the clicking noise that went away when the oil change was probably hydraulic lifters that were gummed up, and flushed out when the new oil with fresh detergents was added.
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  #36  
Old 19 December 2007, 07:17 PM
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Roadsterboy Roadsterboy is offline
 
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Quote:
Originally Posted by Shadowduck View Post
Hydraulic tappets can become noisy if the oil level is low or if the oil is old and has lost viscosity. So new oil (or sometimes a top up) can fix top end noise.
This happens to my car, typically around 4-6000 miles. It is just something that happens to this particular engine, as the oil loses its viscosity, and it happens sooner in the middle of summer than in the winter. Supposedly, using the expensive synthetic oils and various additives will "cure" this, but the cost per hassle ratio doesn't add up for me.

Quote:
I'm not sure about the three months thing, because I don't think oil breaks down just by sitting around. At least not that quickly. Otherwise wouldn't oil need a 'use by' date on it?
No, but you will get condensation forming in the engine, even as it sits unused (unless you're in a very arid, or cold, area), and we all know about oil and water. Plus, the condensation will often settle in the top end of the engine (you'll see a milky white buildup inside the oil cap, which looks like mayonnaise). Now, this won't cause an immediate engine failure, it is certainly not good for it either.

Out of curiosity, has anyone ever actually seen unchanged, year or more oil as it comes out of an engine? Not on the end of the dipstick but as it's coming out the sump plug? It's usually about the consistency of water-I can't imagine that it's doing much good at that point.

-Doug
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  #37  
Old 19 December 2007, 07:58 PM
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Hero_Mike Hero_Mike is offline
 
 
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I change my oil about every 5,000km, or twice a year since I don't drive my car very much anymore. It is entirely possible to go longer, but the engine oil made for cars is not as good as the commercial-grade lubricants used in, say, transport trucks. With these, you can run about 100,000 miles on the oil, at which point it is tested and the depleted additives are replenished. You repeat this test and replenish procedure every 50,000 miles. You can usually get 250k to 350k miles without ever completely draining the oil. Of course, this kind of oil, and this kind of testing procedure, are prohibitively expensive for passenger cars - even luxury cars - but they do work.
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  #38  
Old 19 December 2007, 10:19 PM
kanazawa kanazawa is offline
 
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Quote:
Originally Posted by Roadsterboy View Post

Out of curiosity, has anyone ever actually seen unchanged, year or more oil as it comes out of an engine? Not on the end of the dipstick but as it's coming out the sump plug? It's usually about the consistency of water-I can't imagine that it's doing much good at that point.

-Doug
My ex-gf's boss had a Dodge Caravan that she bought new and just used for kicking around. I think it had 37K miles on it before the first oil change. I drained less that a quart out of it total. It was black as hell of course, but not thin. I know 5W-30 is amazingly like water when drained hot.
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  #39  
Old 20 December 2007, 03:30 AM
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Oil pressure lights have little to nothing to do with how regularly you change your oil. I have driven trucks for over 13 years, and well over 1 million miles in them. I have driven only one truck that had an engine blow, and that was about 2 weeks after an oil change. The oil pump failed, causing the engine to seize. The oil pressure gauge (not light) only indicated low oil pressure immediately after the pump failed, but I did not shut the truck off in time to save the engine. Bearings seized, piston rings seized and all kinds of nasty things happened to the engine on failure. This is in a truck that had well over a million miles, and had the oil changed approximately every 30000 kilometers (which was about once a month). This truck in particular held 15 gallons of oil in the pan, and was usually black as tar after 1000 kilometers. This is typical for a diesel engine, so judging whether it needed a change was impossible by looking at color.

I have an 18 year old BMW that I change oil and filter when I hit around 3000 miles. I use mineral oil, and don't use any oil in between changes. My friend has a 2003 BMW, on synthetic oil, and he changes at the recommended 12000 miles (roughly 20000 kms). In previous cars, I didn't change oil regularly, and had nothing but problems. My last 4 or 5 vehicles, I changed the oil at the same interval as I do now, and have not had an engine failure since. Either oil changes work, or I'm buying better quality cars.

Abuse your engine, it will still outlive the car.

Actually, around here it's the opposite. Most people think my 1990 BMW is at least a 2000 if they are not familiar with the body style changes, and I've been told by US Customs Inspectors when I cross the border, that my engine and engine compartment is cleaner than some cars only a couple of years old. The engine runs very well, my only disappointment is crappy gas mileage compared to other cars I've owned (though it gets exactly the USA EPA rating, and it IS a big car) but the chassis required some suspension work. I abused the engine on my 65 GTO, and it only lasted about 6000 miles before needing engine work. Extensive engine work. This was not the original engine in the car, the original was long gone, and had at least 3 engines in it before I had it, I owned it from 26 to 33 years old. (The car, not me)
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  #40  
Old 20 December 2007, 04:36 AM
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Morrigan Morrigan is offline
 
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I go from 5,000 to 8,000 miles. I change the oil, the filter and I use synthetic.

Morrigan
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