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VW Passat TDI

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Comments

  • sebring95sebring95 Posts: 3,233
    Regarding coasting: of course, the car consumes less gas idling in neutral than it does in gear.

    Actually, that's not true. When you push in the clutch or coast in neutral, the engine burns fuel just as if it was idling in the driveway. When coasting in gear, the motor is actually turning with the transmission and not burning fuel. I was skeptical a few years ago when I first heard this, but confirmed with VAGCOM software hooked to my TDI. If I coasted in gear, the fuel injection drops to 0g/second. At about 10mph, there's not enough power available to maintain and the injection will kick back on. When idling or coasting in neutral, it runs at about .9g/sec. Turn the A/C on while idling and it consumers 1.2g/sec. (i believe those are the right numbers, it's been awhile.... :) )
  • Wow. I'm learning something.

    Now is this true just of the TDI? Or all cars?
  • One more question: Long ago, I heard that diesels use very little fuel at idle, much less than a gasoline engine.

    Izzat true?
  • sebring95sebring95 Posts: 3,233
    I used to think it was just the diesels that didn't burn fuel when coasting in gear, but it's been rumored the gassers do it as well. I can't confirm that though.

    If I ever come acrossed a gasser VW I can hook my VAGCOM to, I'll find out the difference in idling. Diesel doesn't use much fuel when idling, but I really don't know how to compare. Diesels are typically smaller displacement than similar powered gassers, so I would thing pound for pound they could burn less fuel. I dunno really though.
  • cosmocosmo Posts: 203
    Coasting with the clutch pushed down for a half mile is cruel and unusual punishment for a throw out bearing. Likewise, I've read several sources that advise against coasting in neutral with an automatic because it hinders lubrication within the transmission. I haven't free-wheeled since I traded my 1959 DKW 3=6 for a 1963-1/2 Falcon Sprint convertible. (Two cars I wish I still had.)
  • eliaselias Posts: 1,934
    t-pie, rent a clue here and learn from those more knowledgeable than yourself about the basics of modern fuel injected vehicles. your "regarding coasting of course" comment is flat out wrong.

    as for driving a 5-speed and stepping on the clutch & coasting, if anything that is more counterproductive and wasteful of fuel than doing it with an automatic/slushbox. for the passat tdi it's an smg transmission not a slushbox so you are doing essentially the same (wrong) thing.

    also your "but of course, taking your foot off gas" comment seems to be equally wrong. however your third item, a question about the auto trans, is a better one. so you don't get a "three-fer" of wrongness for your post ! go for it next time if you dare - what other wild & wacky driving techniques do you have.

    to answer your question: IF volksy programmed & designedtheir trans properly, it should be fine to go in and out of neutral at any speed. however that's a big IF - you may be aware of the BUCKING issue on these passat TDIs - they all do it - but the gassers do not - i consider it an indication of a design/programming flaw.

    as for the final question, a way to go from 1,2,3,4,5 to N, that's a good question, i have actually wanted to do that on rare occasion such as stopping in a parking lot. but not for the reasons you are doing it.

    happy & safe motoring to ya! if you are going to use driving techniques wasteful of fuel, at least you are doing it in a diesel and wasting that much less fuel ! you go!
  • Likewise, I've read several sources that advise against coasting in neutral with an automatic because it hinders lubrication within the transmission.

    How would that be different from idling in neutral at a stoplight? Either way, the engine is idling and the transmission disengaged.
  • Coasting with the clutch pushed down for a half mile is cruel and unusual punishment for a throw out bearing.

    Can you elaborate? The clutch is disengaged, hence no friction or wear on the clutch. What is the throw out bearing, and how would this driving style affect it? I drove my 5-Speed Legend 200,000 miles using that technique. And never once had the clutch serviced.

    Appreciate your insights.
  • t-pie, rent a clue here and learn from those more knowledgeable than yourself about the basics of modern fuel injected vehicles. your "regarding coasting of course" comment is flat out wrong.

    as for driving a 5-speed and stepping on the clutch & coasting, if anything that is more counterproductive and wasteful of fuel than doing it with an automatic/slushbox.

    also your "but of course, taking your foot off gas" comment seems to be equally wrong. however your third item, a question about the auto trans, is a better one. so you don't get a "three-fer" of wrongness for your post ! go for it next time if you dare - what other wild & wacky driving techniques do you have.


    I am happy to learn from others here. It's good stuff.

    Sebring made the case as to why a car coasting in gear uses less fuel than one out of gear.

    However, you have to judge the circumstance, no? If you are intending to slow down (for a light, toll booth, etc) then it makes sense to take full adavantage of engine braking while also saving fuel. But if your intention is to maintain momentum and let gravity work for you, coasting out of gear is going to cover more distance on less fuel than coasting in gear and suffering engine drag. Now, it still may be a bad habit in the Passat if there is some science to demonstrate that it is harmful to the car to go in and out of neutral while moving.
  • enzanbenzanb Posts: 1
    Have heard about the 7500 miles needed for registration clause, but suppose I buy the TDI out of state, with residency in that state of purchase and then move to California say within the first 2000 miles. Any help? Thanks.
  • eliaselias Posts: 1,934
    hi t-pie. i was a bit rude - sorry about that. re your idea about intending to maintain momentum and let gravity work for you, i still think it's a "win" to keep the car in gear. fwiw, coasting in neutral is actually illegal in some states! i can't imagine the cops ever citing someone for that unless the driver got into an accident and admitted he was coasting in neutral intentionally. best regards.
  • cosmocosmo Posts: 203
    I admit I'm new to the world of automatics, but I've been driving 3-on-the-column, 4-on-the-column, 3-on-the-floor, 4-on-the-floor, and 5-on-the-floor (all with clutches) since 1963. I'm sure the driving instructor who told me to put the clutch in ONLY when I shift and the VW mechanic who tried to politely explain to my first love (a blond) in 1965 how she ruined the throwout bearing in her cherished Beetle are both dead now, so I can't call on them to present their reasoning. However, there are some living resources available.

    There are a multitude of discussions on this and related topics in other forums. So as not to offend our host, I suggest doing an Internet search if you are curious.

    Information not contained in other forums is also available, and I'll provide some samples for your review.

    This one address the practices of shifting an auto into neutral at traffic stops and holding the clutch down at traffic stops.

    http://www.popularmechanics.com/automotive/sub_care_clinic/1675807.html?page=2&c=y

    This one addresses a warning in the operators manual for Allison automatic transmissions. See page 7. I assume the torque converter style Tiptronic is similar.

    http://www.allisontransmission.com/servlet/DownloadFile?Dir=publications/pubs&FileToGet=OM- 1334EN.pdf

    Tom and Ray seem to expound endlessly on this topic, and here are some samples of their offerings.

    http://www.cartalk.com/content/columns/Archive/1996/September/05.html

    http://www.cartalk.com/content/columns/Archive/1994/May/07.html

    http://www.cartalk.com/content/columns/Archive/1995/March/18.html

    http://www.cartalk.com/content/columns/Archive/1995/November/09.html

    http://www.cartalk.com/content/columns/Archive/1993/April/10.html

    http://www.cartalk.com/content/columns/Archive/1995/October/07.html

    Bottom line, as already pointed out, the practices of coasting in neutral and coasting with the clutch down are both illegal. That may explain why DKW 3=6's and Rambler Americans with freewheeling overdrives are no longer made. ;)
  • Cosmo, :)

    Much appreciated! I had heard some of these things before, but always second-hand. And I figured they were as reliable as "don't go swimming after you eat" and "add ten pounds of tire pressure for long trips."

    Consider me educated on this topic, even though I logged over 400,000 miles between my Civic and my Legend and never had an issue. My two cars are hardly a statistically valid sample.
  • Anothre question re fuel economy: My Passat, as did my Acura Legend, came equipped with Michelin MVX tires. The handling is good, not great. But I did notice a drop in gas mileage, almost 10%, when I wore out the tires on the Acura and replaced them with Dunlops. The Dunlops had wonderful handling, wet and dry pavement, but wore out quickly. I then went to el cheapo Kumho Korean tires. They actually performed pretty well -- better handling than the Michelins, better fuel economy than the Dunlops. What is the general wisdom on rubber? Are the Michelins worth the high price? Can other tires deliver the same fuel savings?
  • I plan to use synthetic oils in my TDI. Change it at 5,000 then every 10,000 thereafter.

    1) Should I go for the new 0W/40W from Mobil for better fuel economy?

    2) Is every 10,000 frequent enough? I am driving mostly highway. Very little stop and go.

    :confuse:
  • eliaselias Posts: 1,934
    the michelin mxv tires are really top notch in so many ways. quiet. low rolling resistance. reasonable handling. the fact that they are the quietest tires is consistent with the low rolling resistance & the fact that they give better mpg. the better mpg is probably a big reason the manufacturers choose them - CAFE.
  • cctdicctdi Posts: 82
    For 04 & 05 tdi the VW gives the strict warning both in Toureg and Passat owners manuals that only 50501 5w-30 oil can be used. To my knowledge, the first two oil changes are 5k-7k, 10k for the rest life of the car.
  • I was reading some posts over at TDI Club, by posters who seem well informed. But much of what they post directly contradicts the owner's manual. For instance, the break-in period. VW says, in essence, drive gently. The guys on TDI Club say city driving, with frequent hard accelerations and running up to 3800 RPMs is good, then right up to the redline after 1000 miles.

    Who's right?

    Further, they go on at length about fuel and fuel additives. With gasoline motors, I have found every fuel additive to be a waste of time and money, except for drygas in the winter.

    Do you put cetane or other additives in your diesel fuel?
  • sebring95sebring95 Posts: 3,233
    I don't know about the break-in, seems to be a lot of opinions. I drove mine fairly normal during break-in.

    Some folks use the additives religiously. I have a good fuel source I always try to use and I don't use the additives. I do carry some with me in case I have to fuel at a questionable spot, particularly in the winter. If it's somewhere I'm not familiar with, I'll use the additives as insurance. I'm coming up on 130k miles and have had very few problems with my TDI.
  • How do you know what is a "good" fuel source?

    I live in the Philly suburbs, with lots of high-volume gas stations -- Sunoco on the turnpike, Amoco, Exxon, Shell, Texaco, etc. I want to avoid the no-name place in the middle of nowhere, same as I did for conventional fuel -- but what else?
  • sebring95sebring95 Posts: 3,233
    Well that's a start, name brands with lots of volume sales. I happen to know the BP/Amoco distributor in my area and know where to buy "bp diesel supreme" which is a very good fuel, higher cetane, very low sulphur, plus it doesn't need treated for winter. It's also more expensive, but it runs quieter and stronger so it's worth it to me. You could start chatting with distributors if you were serious about it. Find who carries the higher quality fuels. Sunoco and BP/Amoco both are supposed to have a premium diesel. There's no legislation regarding premium diesels though, so even though the pump might say "premium" like most Sunoco's, that doesn't mean it's actually their premium product.

    Easiest way if you can't find out who carries the premium fuels, is to fuel at different places and see which one makes the car run better. If it gets cold and you don't know for sure you're buying premium fuel, throw in the additive. I carry Power Service (white bottle) purchased from the local wally-world for about $4 a quart. A few ounces will do the trick.
  • eliaselias Posts: 1,934
    hey there t-pie. hmm, you mentioned another forum, -usually those posts get deleted. but anyway, to answer your question - i prefer to break in cars hard - as described in that other forum. whether i'm right to break-in cars like this, maybe i'll never know, since i never kept a car beyond 100k. i traded 2003 jetta TDI for 2005 passat tdi when the jetta had about 65000 miles.

    regarding additives, i don't use them except when the daily temp drops below 10F. or maybe 20F. above 20F i never use additives. with the jetta i used "white bottle" powerservice. it made a big difference on cold winter starts & how smoothly the engine would run when really cold - and much smaller mushroom clouds from the exhaust at startup. :| i'm not sure how the passat TDI will do on cold starts this winter but i will probably follow the same policy with the white powerservice bottle stuff.
    last winter there were a couple of days when the low-temp in my back yard was colder than the high temperature on mars as measured by those nifty mars rovers. i love it when that happens. so according to my policy, i should use cetane boost when driving my TDI on mars. gotta keep that in mind..
  • patpat Posts: 10,421
    If you have questions about our policies that are not answered by a review of the Membership Agreement and/or Rules of the Road (links on the left side of the page), feel free to email me - no need to be puzzled about them. :)
  • cecirdrcecirdr Posts: 9
    I have a dealer about 30 miles away with an '05 GLS TDI in stock. He has no '06 VWs on his lot yet. (nor do the other local VW dealers....is Oregon out of the loop?)

    I had been contemplating a jetta TDI since the '06 passat didn't come as a diesel. Also because I can get the jetta diesel in manual. But other than that (and the dynaudio option in the new passat) I can't see a reason to not consider the '05 TDI.

    I plan to test drive it tomorrow afternoon. What do folks here think would be a good offering price for it?

    Thanks,
    Ceci
  • gagricegagrice San DiegoPosts: 29,043
    I bought mine at Armstrong VW in Oregon below invoice. I love it so far 4500 miles.
  • I got my 2005 Passat GLS TDI for $23,675 in early August. Below invoice, and I didn't even have VW loyalty bonus.

    I think I could have waited and got it even cheaper, but since the new Passat is not coming with the TDI, I figured the supply might dry up.
  • Contemplating a new TDI.
    Tried out the '04 Jetta last year, and found the rear seat a bit to tight for our needs, so was thinking Passat may be the way to go, but have heard the new model Jetta is quite a bit roomier than the old.
    Just got a dealer quote of 26,000 on a decked out 05 Passat GLX TDI wagon with a list of 31,000. But am wondering if the lesser MPG of the Passat is worth the extra room, and even if there is that much more room compared to new larger Jetta?
    Also wondering why VW has decided not to offer either the TDI, or the wagon in the Passat line in 06, and if that will have any effect on the value of the current ones??
    Any one out there who had some of the same thoughts in making their decision, have any insight they'd care to share?
    Thanks!
    sandman 52 :confuse:
  • Just realized the quote I received from the dealer wasn't for a TDI, since the GLX doesn't offer the TDI, so that part of my post obviously is incorrect, but still would like to hear from those who have made the decision between the two vehicles, and why they made the choice they did.
    Thanks again :confuse:
  • I just made that choice 3 weeks ago. The Passat is much more car than the Jetta, and is built in Germany still. Adult leg room and head room in the rear seats.

    I found that the 2005 TDI GLS was about the same price as the 2005.5 Jetta TDI. Since I plan to keep the car a long time, I don't care if it's resale value dips due to the new style Passat. The new Passat cannot be had in diesel this year. I found that the supply of Passat TDIs was drying up fast, so I bought mine before there is a bidding war. I bet you could drive it a year and then sell it in NY or CA (where new diesels are banned) and get almost what you paid for it.

    My 48 mile (each way) commute is mostly highway and, with the car not yet broken in, I am getting 41 mpg. Sure, I'd do better in a Jetta (which now looks like a Corolla) but I LOVE this Passat TDI.

    Hope that helps. I paid $23,677 in early August. :)
  • Thanks for the input. You made some good points, and it sounds like you got a nice price. Was that a sedan, or wagon, and how did that compare to the sticker??

    Thanks :)
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