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Discussion Starter · #1 · (Edited)
Long...

So, a couple weeks ago I'm sittin' in the X, at the farmers market.. waiting for my wife, who loves to go there to shop for farm fresh veggies [I'm content with listening to tunes and laying in the sun.. ahhh..]. Our regular Saturday morning ritual. Anyway.. "Car Talk" is on the public broadcasting station. You guys have heard of them right? National show. Very funny.. although sometimes ridiculing ... car technical advice for callers.

So this girl calls in and wants to know whether her boy friend is right or not, about his assertion that she's gonna toast her engine, prematurely, due to making daily VERY short trips. SHe thinks he's wrong.

The car talk boys ask what her situation is. She lives in San Fransisco. In town. Like, a cool little town house. Her work is 1 mile away. She drives to work in the morning, but then.. drives home for lunch, then drives back to work again, then drives home again. 1 mile each time. Did I mention she has a nice car. It's a Bimmer or a Porsche, I can't remember.

The Boys go nuts. OMG YES, your boy friend is right. You're gonna fry that engine. Give up the ghost waaay before it's time!

Then they give her a little crap about why she doesn't just walk. Now, actually... I'm with the caller on this one; She has a nice town house with a nice view of the bay and the city. She can stay at work.. a place with no windows or a nice place to "break", or she can get lunch out.. which in SF either means paying for a very expensive lunch, or getting a hot dog at a sidewalk vendor (anybody living in SF knows what I mean. Limited food choices), or she can go home to her nice view.. which.. I'm sure she paid a lot to get. If she walks the one mile and then the one mile back, this gives her only 15 minutes to eat, and probably no time to just sit down and enjoy the view. Clearly, if she takes her car, she gets waaay more time to relax. Incidently.. yes.. she does have assigned paid for parking at both locations.

The boys say, 1 mile isn't enough time, even in the summer, for the engine to warm up enough to burn off the water and raw fuel that have made their way into the crank case. That the accumulation is normal, but it takes 5 or 6 miles to do the job.

In the end, she agrees to take "the long way home" every 4 days or so. At least 10 miles they say. Still, they think her engine's future doesn't look good.

:rolleyes:

Well... I drive 5 miles to work and 5 miles back. But.. everyday at lunch, I drive 1 mile to get some food, and then 1 mile back. Ooops. Looks like half of my situation is just like hers. Yes.. I could bring my lunch. Boring. I work my arse off just so that I don't have to bring my lunch to work. Besides, I LOVE my Bimmers and I love to drive them.. as much as possible. I really look forward to getting out in my X5 or my Z3. Some times I walk, when the weather is nice.. but she's right.. that leaves only 10 minutes to scarf down some food.

Sooo... am I a bad kid? Am I cooking my engine(s) by doing this? Perhaps the car talk boys are just plain wrong on this one (hope).

Opinions?

P.S. The car does get taken out on longer drives on the weekends. Plus, I'll take "the long way home" (10 miles) at least once during the week.

P.P.S. Editing my post; I just realized, I frequently make an extra trip into down town each day. So that.. (4) 1 mile trips. One step closer to doing precisely what the girl in SF does (morning and afternoon commutes are longer.. being the only thing that now separates our situations). Yikes. :throw:
 

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I had the same type of situation with one of my old cars. 5 minutes to work and back home with minimal highway driving. 8 yrs and 130000 miles later the engine was still going strong. No oil consumption, leaks, etc.

I'm with you that I love driving the X. My situation is different now however. I have a 22 highway mile one way drive to work. My service lights didn't trun yellow until 17200 miles due to all the long travel, so I don't have many worries about the moisture in the oil.

I agree that the engine does need to get warmed up so the oil can release the moisture that it accumulates. Either that or change it more often. There was a good post on RF about that very subject some time back.

But hey, we bought them to drive, so do it. :thumbup:
 

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Discussion Starter · #3 ·
MatriX5 said:
But hey, we bought them to drive, so do it. :thumbup:
Thanks MatriX5. What was the threads conclusion on oil changes?

I used to do 2 extra oil changes. So that's; Dealer does one, for free.. then I pay for two additional ones, for a total of 3. Comes out to about, every 5,000.

But the cost was getting me. I'm now doing only one extra oil change for the cars. Every 7,500 miles.

I realize I could do the oil changes myself, and with the price of oil, and three M54's to feed, it may come to that. But.. I already put hundreds of hours into DIY mods, doing my own brake pads and such, and, detailing the cars. I kinda draw the line at doing my own oil changes.

But.. if the concensus here was that I was risking premature engine wear, and that I should change the oil every 5,000, I would very sharply consider going back to that schedule.
 

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The conclusion was under severe conditions (ie short trips in colder climates) it is pretty cheap insurance to do an intermediate oil change. There were some pictures of an oil filler cap with foamy oil and rust where shiny metal should be. That, I would think, is an extreme situation, but it does show what can happen on occasion.

I do mine every 5k anyway because I'm just anal about it. It only costs me about 40 bucks and an hour of my time. I like tinkering (brakes, aux cable, stealth one, etc.), so I don't mind an hour every once in a while. Most fellow Xers do the 7500 intermediate from what I have read here and elsewhere.

I think the best advice is just to keep your eye on things and do regular maintenance whether it be once every 7500, 5000, or when the yellow light comes on. Personally, I still can't just trust the lights every 17000. Too much of my dad in me I guess.

I guess Turdfly is down or something. If you go there and search for withidl (that's the user that posted the info) you will find several good postings regarding oil life, degredation, etc. Oh, by the way...

TurnAround said:
and with the price of oil, and three M54's to feed
I guess it's a tough job but somebody has to do it, huh? :rofl:
 

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MatriX5 said:
I had the same type of situation with one of my old cars. 5 minutes to work and back home with minimal highway driving. 8 yrs and 130000 miles later the engine was still going strong. No oil consumption, leaks, etc.

I'm with you that I love driving the X. My situation is different now however. I have a 22 highway mile one way drive to work. My service lights didn't trun yellow until 17200 miles due to all the long travel, so I don't have many worries about the moisture in the oil.

I agree that the engine does need to get warmed up so the oil can release the moisture that it accumulates. Either that or change it more often. There was a good post on RF about that very subject some time back.

But hey, we bought them to drive, so do it. :thumbup:
Your oil filter doesnt last all the way to 17k miles. At a MINIMUM you should change the filter out in between.
 

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TurnAround said:
I work my arse off just so that I don't have to bring my lunch to work.
My guess is that, if you appreciate the luxury of going out to lunch, you also appreciate the luxury of a new car every several years. My uneducated impression is that short trips really only wear on the core components of the engine but that it'll take upwards of 10 years for the engine to actually fail. For example: a Chevy suburban taken along a 1-mile route, four or so times per day, ran fine until one day the block just split after about 12 years of the same abuse.

Click & Clack style themselves as guys who have worked on a lot of old junkers. For an old car, short trips would be a big red blinking light. With air-horns. Possibly barracades. But unless you plan on keeping the car until it goes bust, you should worry less and drive more. If you do plan on running the Bimmer dead, taking the scenic route home has now become routine maintenance. :D
 

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If you frequently drive short trips, you want to give your X5 one long trip (20 miles or so) every couple weeks. This burns the moisure out of the oil, and the rest of the system. Drive it at highway speeds for a long trip - watch how well it runs the next day!

It is true it takes at least 5 minutes of driving for the oil (and everything else) to heat to operating temps. The gauge on the dash, for water temp, will jump to the middle in about a minute - but the oil still isn't hot.

My P-car has an oil temp gauge. It takes me about 10 miles (12-15 minutes of driving) before the oil is at 175 F (operating temperature).
 

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Discussion Starter · #9 ·
Pock said:
you also appreciate the luxury of a new car every several years. it'll take upwards of 10 years for the engine to actually fail.

But unless you plan on keeping the car until it goes bust, you should worry less and drive more.
Thanks guys (everyone) for the feedback.

Before owning Bimmers.. yes, we're exactly the kind of people to want a new car every few years. I don't know how to fully explain it (but if anybody would understand.. you guys would :) ), but after we bought the X5, we went nuts over BMW, and wanted to get the Coupe too. Then.. the Roadster. It's a sickness, I know. But part of the "stretch" for us to land these three cars.. in less than 18 months... was that we would most definitely keep the Z's.. forever. Those cars are timeless classics and will never be made again. The X.. we feel the same way, but we also recognize that it needs to be 1000% reliable because we take it on long trips around the western US. It's not beyond reason that we'd need a new one some day. But with the Banlge f-ing that has been happening to BMW, we don't have high hopes for future X5's. I'm sure they'll look like FX 45s or something.

I'm fully prepared to reuild or replace an engine (or three) in 10 years. I should have the money then (don't now). I don't have an option on the Z's (total heart break to sell).

Sooo... I guess I'm glad that I caught that radio show, eh! And, I'm really glad this board is here to ask and verify with!!

Looks like the wise thing to do would be to figure on some extra miles. Let the ponys out more often. :thumbup:
 

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Emission said:
My P-car has an oil temp gauge. It takes me about 10 miles (12-15 minutes of driving) before the oil is at 175 F (operating temperature).
Very true but your Porkchop has like 12 quarts to heatup ;)

I think changing oil more often is a good and cheap insurance. We may all discuss how often it should be changed but truth is everyone's driving situation is different. I suggest to do used oil analysis around 5,000 miles, get TBN checked and see how much additive is left, then follow up at 7,500 miles. This way you can establish oil change interval for your driving conditions and oil that you use. It is very easy to take a sample if you have oil extractor (MightyVac) or you can get a sample when you open the filter cap. Full analysis with TBN is $30 from Blackstone lab and around $10 to test TBN only.
 

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vinu_neuro said:
Your oil filter doesnt last all the way to 17k miles. At a MINIMUM you should change the filter out in between.
What did I say in my second post?

MatriX5 said:
I do mine every 5k anyway because I'm just anal about it. It only costs me about 40 bucks and an hour of my time. I like tinkering (brakes, aux cable, stealth one, etc.), so I don't mind an hour every once in a while. Most fellow Xers do the 7500 intermediate from what I have read here and elsewhere.
:dunno:
 

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This thread has discussed the issue already........

http://www.bimmerfest.com/forums/showthread.php?t=92447

In my limited mechanical knowledge, I understand that cars run rich fuel settings while they are warming up to operating temp.

Running rich 'washes' the bore quicker of oil and increases wear.

Running rich all the time can cause excessive carbon build up and eventually pre-ignition (knocking) that can be fatal to pistons, unless the engine computer retards the timing (de-tuning)

It depends on the performance level of the car, state of tune, mapping of the fuel curve and all sorts of things.

Either way it can cause a lot of trouble if it is repeated over a long period of time.

12 months of a similar thing led me to a rebuild of a highly tuned V8.

Long trips are needed....
 

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Discussion Starter · #13 ·
After being fully heated, how long before cool down?

Ok then.. I just thought of a question that might help me out in some situations.

Let's say the oil is fully heated, and then one stops and parks it. I know the engine stays warm for a while. How much time has to elapse before the oil is considered "cooled off too much"? By this I mean, if you come back out to your car within 40 minutes and start it back up, are you starting the clock over again for oil heat up? Or is the oil considered warm already, and it's as if you hadn't turned the car off earlier on.

Depending on what that time frame is, and of course the time of year (outside temp) this could mean that the mileage of one short trip out, is really combined with the mileage of one short trip back. ??
 

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TurnAround said:
Ok then.. I just thought of a question that might help me out in some situations.

Let's say the oil is fully heated, and then one stops and parks it. I know the engine stays warm for a while. How much time has to elapse before the oil is considered "cooled off too much"?
It's not the temp of the oil, rather the coating of all the parts.

Warm oil is circulated freely throughout the engine. It flows into all the nooks and crannies, for lack of a better definition. Cold oil is thicker, less likely to flow. Metal parts with insufficient lubrication will wear faster.

To compound the problem, cars that have been sitting for a long time will have the oil drip to the bottom of the engine (you know how you turn the soap or syrup bottle over to get every last drop) and the parts won't be coated during the first few seconds of start-up. If you just ran your car a few hours earlier, it is much less of an issue.

BTW, synthetic oil (factory fill in BMW's) has excellent cold flow characteristics and coats parts much longer after they are "parked" for periods.
 

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Discussion Starter · #15 ·
Ok, that's what I thought. That between the newer oils being synthetic (not only last longer, but grip to stationary engine parts longer), and the fact that the car is only sitting for 50 minutes (length of a lunch break, minus the drive back and forth), or for only 5 minutes (length of a coffee break, minus the drive back and forth)... that there should be less of an issue. That these facts would diminish the "short trip" wear issue.

I know with older carburated engines, the starting process allows a small amount of raw fuel past the cylinder walls and into the crank case. Least.. that's what I was taught. So the idea was.. lots of cold starts meant that you were accumulating raw fuel in your oil supply. Not a ton, but enough that it would dilute the oil. Dino oil, of course though. With fuel injectors, synthetic oil, and modern 10 to 1 compression pistons (translates to more rings, and snugger fit to be able to achieve high compression) seems like the raw fuel in the oil thing wouldn't happen. ??

But lastly then.. Where does the water come from? DOes it simply condense on the walls of the crank case, from the small amount of air inside the engine (non combustion sections of the engine)? It sounds like the water is the threat here (If the purpose of long trips is to burn it off). How does it get in there?

Thanks.
 

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TurnAround said:
But lastly then.. Where does the water come from? DOes it simply condense on the walls of the crank case, from the small amount of air inside the engine (non combustion sections of the engine)? It sounds like the water is the threat here (If the purpose of long trips is to burn it off). How does it get in there?

Thanks.
Unleaded gasoline is comprised of fuel molecules (hydrocarbons - HC's). When burned, it creates water and carbon dioxide (and a bunch of other really bad stuff like carbon monoxide, when combustion isn't complete). So, basically, combustion creates water - this is why exhaust systems used to rust out so fast (before stainless steel systems).

I think the hotter the oil and engine, the less likely that water is able to "stick around" in the system. Hot = evaporation.
 

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even eliminating the water in the crankcase.... there is still the issue of wear and carbon build up

cars run rich fuel settings while they are warming up to operating temp.

Running rich 'washes' the bore quicker of oil and increases wear
 
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