Letting my TDI idle

JorJetta

New member
Joined
Sep 9, 2011
Location
Oklahoma
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2006 TDI Jetta
I read on here that it isnt recommended to let my TDI idle for long periods of time (which i wouldnt want to do anyway because it makes a weird sound when its idleing), But I read that to my boyfriend who is a diesel junkie and he says he doesnt understand what oil consumption while idleing has to do with the clogging the catalytic converter. Can someone explain that to me please? :)
 

VeeDubTDI

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Springfield, VA
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Drive more, worry less... that's what I say. ;)
 

whitedog

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Jul 12, 2004
Location
Bend, Oregon
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2004 Jetta that I fill by myself
Oil consumption during idling is caused by oil passing the seals in the turbo. So now there is oil in the intake system being burned in the engine causing excessive ash that can clog the catalytic converter.

Have the BF take you to a nice dinner for doubting you.
 

40X40

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Kansas City area, MO
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2013 Passat SEL Premium

Corsair

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Weedsport, New York
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2002 Jetta GLS TDI 5M
my 0.02 jut my 0.02, others will have different 0.02...

This is a fairly polarizing topic that comes up regularly.
my 0.02, and I respect that others may have different 0.02-
=
Although I don't have specific examples of why, I tend to agree it's probably not good to allow the TDI to idle for extended periods of time. The above replies explain that. Others will say that's garbage, idle for as long as you want.
=
I am a fan of NOT shutting the engine off immediately when you stop- allow it to idle for 30 seconds or so, maybe a bit longer on a hot day. Why? Because it has a turbocharger. Part of the turbocharger sits in the exhaust stream, and gets very hot when the engine is working to produce power. (the engine produces relatively little excess heat while idling). The turbo has spinning parts, which are lubricated by oil fed from the engine. There is a pressurized oil line that goes from the engine to the turbo, and a little drain line that takes the oil out of the turbo and back into the engine oil pan. In addition to lubricating the turbo, the engine oil helps to cool the turbo bearings. So what you're doing when you idle for 30 seconds or so (bit longer on hot days), is allowing some time for the turbo to cool down, so that when shut off, the hot turbo doesn't cook the oil that happens to be left in it at the time. That's one of the reasons these cars call for using synthetic oil- because synthetic is capable of handling slightly higher temperatures than conventional oil without "coking". When I first bought my 02 jetta (new), this was recommended to me by a friend who had been a technical salesman for a big diesel engine manufacturer. I'm just coming up on 300K miles on original turbo. I have seen reports from others about high miles with no problems, and they don't "idle down".
=
Still, I agree with the above- your BF should buy you the dinner of your choice. ;)
 
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VeeDubTDI

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We've gone around this block at least a dozen times already. Idling isn't going to destroy your engine. Idling isn't the ideal condition for your engine to operate at for long periods of time. Decide for yourself how important idling is to you and do what you want with your car.
 

VeeDubTDI

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Also, there are two separate topics being discussed here.

First is the question of idling after driving for a "turbo cool-down." Turbo life is determined by a number of factors, one of which is "cool-down," and arguably has little impact on turbo life in the typical TDI's life cycle.

The second topic - which this thread is about - is about idling for extended periods... example: waiting for your kids in the pick-up line at school and idling the engine for air conditioning on a hot day. Again, discussed ad nauseum with a wide variety of answers. Long story short: do what makes you comfortable, your car isn't going to spontaneously combust.
 

SnieselDiesel

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Joined
Aug 5, 2010
Location
Washington, VA.
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2012 Jetta TDI 6MT
Now, in semi's, we would typically let them idle all night long. And drive for weeks at a time. What is the difference?

What would be a 'safe' idle time for these cars?
 

Cogen Man

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Kingston, Ontario, Canada
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2011 Golf TDI DSG.
Corsair said it best. And ask all the questions you like. That's what a forum is all about. There are no dumb questions. Some will say, do a search. You'll get that response from a lot of folks. Mostly the long time members. Now go get that dinner from the BF. ;)
 

VeeDubTDI

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There is no safe/unsafe idle time. It's up to you to decide what's best for your car based on its condition, your daily routine, your maintenance budget, etc.
 

> Luke <

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West Los Angeles
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Fm > White Dog
Oil consumption during idling is caused by oil passing the seals in the turbo. So now there is oil in the intake system being burned in the engine causing excessive ash that can clog the catalytic converter​
Fm > Bill
+1​
May I second the above comments.....It would be very noticeable when you take the cat off and try to look through it.
 

Keith_J

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Apr 12, 2007
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West
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2000 Jetta MT
Many older engines have flat tappet cams, the wear per engine revolution is greatest at idle since the friction pair speed is lowest. This places a greater burden on the oil film lubricating the surfaces. Just like your car won't hydroplane at 5 MPH but will easily do it at 70 MPH, speed matters. Only you WANT the tappet to hydroplane over the cam lobe.

On the catalytic converter issue, idle speed has very low exhaust gas temperature, this can cause carbon buildup on the converter.

Yes, OTR diesels idle overnight. Some have roller tappet camshafts (as do most modern gasoline engines). Still isn't good for them.
 

jettawreck

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Aug 2, 2004
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Northern Minnesota-55744
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2001 Jetta and 2003 Jetta
Now, in semi's, we would typically let them idle all night long. And drive for weeks at a time. What is the difference?

What would be a 'safe' idle time for these cars?

I have to let mine idle for 20 min now and then in the winter and seems to do no harm, but don't recommend it if you can avoid it. I wouldn't do overnight/extended idling. Cann't tell you exactly why it, just when most all the guys whose opinions I rely on say its not good, I listen. But sometimes you still have to do what you have to do.;)
I think the biggest difference is the variable vanes in the turbo getting sticky and the way the turbos are constructed and the speed at which they operate.
 

Henrick

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Aug 24, 2010
Location
Ireland
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Golf VI TDI, 77 kW (CAYC)
There are tons of TDIs with clogged intakes which did only highway cruising and almost no idle at all. There are some TDIs which did some idling but still have (relatively) clean intakes. In short, idling a TDI doesn't mean a conclusion that your intake will clog.
 

40X40

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Location
Kansas City area, MO
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2013 Passat SEL Premium
There are tons of TDIs with clogged intakes which did only highway cruising and almost no idle at all. There are some TDIs which did some idling but still have (relatively) clean intakes. In short, idling a TDI doesn't mean a conclusion that your intake will clog.

I think you are the first one to mention idling resulting in a clogged INTAKE.

Maybe I missed it in another post. ULSD has reduced intake clogging to nearly nil.

Bill
 

NickBeek

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Upstate, SC
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2013 Passat TDI 2006 Dodge Ram
I am on my phone so I can't see who has which type of car. Older diesel engines with other than CR injection systems were not as affected by idling as the CR engines are. This may be more related to CR emissions strategies and less related to the CR technology itself. I can tell you this much first hand, idle your CR Cummins powered Ram too long and kiss your engine warranty goodbye. The ECM in those vehicles actually monitors idle time as a percentage of total run time and that is one of the first things the tech will look at if you go in for warranty work.

As far as big OTR trucks idling A) they sometimes have no choice because the driver needs heat to stay alive. B) when done idling they typically run for hundreds of miles at near max output thereby burning off all the buildup in the combustion chambers and on the injectors, valves, and rings. What's more, newer trucks are more and more coming equipped with alternate power units (APU) so that they don't have to idle the main engine.

Bottom line is don't needlessly idle your new CR TDI. If you have to idle it for extended periods, a good long spirited drive is in order as soon after as possible.
 

AndyBees

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Joined
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Location
Southeast Kentucky
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Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
Without reading any of the comments posted, here is my two cents.

1. Ever get caught in a traffic jam during rush hour? What did you do, cut-off engine?

2. Ever get caught in a traffic jam due to an accident? What did you do, cut off the engine?

I had only owned my TDI two weeks and was stuck on the Interstate for over 6 hours idling the engine just to keep warm ...........that was well over 200k miles back.

For the last 9 years, my wife and I have "taken in" the Highway 127 yard sale which is held the first week of August..........never cut the engine off all day long to keep the AC going.

The TDI has a good oil pump system! The seals in the Turbo are metal rings just like Piston rings........one on each end of the shaft!

It's a diesel ....... if you need to let idle, do it! Or, don't do it!
 

JettaTDiPA

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Joined
Aug 13, 2011
Location
Northern PA
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Owned 2011 JSW DSG for 16mo.
Now, in semi's, we would typically let them idle all night long. And drive for weeks at a time. What is the difference?

What would be a 'safe' idle time for these cars?
These are VW cars, not freightliners. Detroit, Cummings, Mac, etc. are not built for the same purpose as the TDI.
 

VeeDubTDI

Wanderluster, Traveler, TDIClub Enthusiast
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Without reading any of the comments posted, here is my two cents.

1. Ever get caught in a traffic jam during rush hour? What did you do, cut-off engine?

2. Ever get caught in a traffic jam due to an accident? What did you do, cut off the engine?

I had only owned my TDI two weeks and was stuck on the Interstate for over 6 hours idling the engine just to keep warm ...........that was well over 200k miles back.

For the last 9 years, my wife and I have "taken in" the Highway 127 yard sale which is held the first week of August..........never cut the engine off all day long to keep the AC going.

The TDI has a good oil pump system! The seals in the Turbo are metal rings just like Piston rings........one on each end of the shaft!

It's a diesel ....... if you need to let idle, do it! Or, don't do it!
And there you have it... do what you need to do; don't do what you don't need to do. :)
 

MayorDJQ

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Location
Williamstown, Mass
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'10 Golf 2dr 6m, sold.
I have to let mine idle for 20 min now and then in the winter and seems to do no harm, but don't recommend it if you can avoid it. I wouldn't do overnight/extended idling. Cann't tell you exactly why it, just when most all the guys whose opinions I rely on say its not good, I listen. But sometimes you still have to do what you have to do.;)
I think the biggest difference is the variable vanes in the turbo getting sticky and the way the turbos are constructed and the speed at which they operate.
But do you actually idle at "idle speed" or an elevated idle? Trucks overnighting at truck stops always sound like they're running faster than idle.
 

VeeDubTDI

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Good question. Fast idle can eliminate most of the problems associated with extended idling, but it burns more fuel.
 

jettawreck

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Joined
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Location
Northern Minnesota-55744
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2001 Jetta and 2003 Jetta
But do you actually idle at "idle speed" or an elevated idle? Trucks overnighting at truck stops always sound like they're running faster than idle.
903 RPM, normal idle. Well, except for the first few minutes when the ECU "high idles" when its real cold.
I own a retail store. We only have on street parking. No where to plug in the Zero Start coolant heater, other than some days when I can drive into the wharehouse area, which isn't often. When its -20F and colder, I start it after lunch time midway thru the day (aprox 11 hrs work day) and let it run 15-20 minutes if I don't get distracted by/with someone. It warms up enough to start easy and reduces the warmup time for the drive home quite a bit.
 
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MayorDJQ

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Williamstown, Mass
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'10 Golf 2dr 6m, sold.
O
903 RPM, normal idle. Well, except for the first few minutes when the ECU "high idles" when its real cold.
I own a retail store. We only have on street parking. No where to plug in the Zero Start coolant heater, other than some days when I can drive into the wharehouse area, which isn't often. When its -20F and colder, I start it after lunch time midway thru the day (aprox 11 hrs work day) and let it run 15-20 minutes if I don't get distracted by/with someone. It warms up enough to start easy and reduces the warmup time for the drive home quite a bit.
Doh!! I misunderstood your earlier (quoted) post. I read it to mean you have a semi, as the previos post mentioned OTR trucks. Hence the mention of trucks idling overnight.

As for starting your car at lunch time, it may help in charging the battery up a littlebut any heat generated will he long gone when you leave.
 

jettawreck

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Location
Northern Minnesota-55744
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2001 Jetta and 2003 Jetta
O

Doh!! I misunderstood your earlier (quoted) post. I read it to mean you have a semi, as the previos post mentioned OTR trucks. Hence the mention of trucks idling overnight.

As for starting your car at lunch time, it may help in charging the battery up a littlebut any heat generated will he long gone when you leave.
Actually its surprising how much difference a mid-day start makes. It certainly doesn't lose any measurable charge in 5 hrs of sitting, nor would 20 min of idle replace as much charge as is lost from pre-glow and cranking. I think residual heat from internal engine metal lasts longer than coolant temp and keeps some things quite a bit warmer than ambient. If it sat all day (11 hrs @ -30F) it would crank slow and run rather noisy for a minute or two vs the rather "normal" cold weather start-up after a mid-day start.
 
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