Knowing when to replace glow plugs

[CatherineL]

Disclaimer: I'm still a newbie when it comes to VW TDI's and I always will be. But, this is the vehicle that I've got -- 2006 VW New Beetle TDI -- and so I very much need advice in order to stay ahead of any problems due to my not understanding this vehicle. What I would like to know is when to expect to replace the glow plugs. Glow plugs were last replaced in Nov 2014 at 87K miles. Mileage is now 143K. I've had the car three years. During the first 2 1/2 years that I drove the VW, the glow plug light stayed on for several seconds once the key was turned on (but the car not started). I had been advised to not start the car until the light went out. Beginning about eight months ago, the glow plug light came on for a nano second when I turned the key and then went off way too quickly compared to previously. Question: What conditions should I be aware of in advance of needing to replace the glow plugs so that I don't find myself stranded and having to be towed? (Senior citizen lady driver here living in rural area where nearest foreign auto repair shops are over 40 miles away, hence my concerns.) Thank you one and all.

 

[oilhammer]

The car monitors the glow system, if there was a failed plug, it would alert you with the MIL (Check Engine Light).

It sounds like perhaps the coolant temp sensor is not sending the correct value, and thus the preglow time may not be correct.

 

[Vince Waldon]

As well, perhaps you'll be happy to hear that in East Texas your car will do a fine job of starting most if not all year round *without* glowplugs (which as posted above won't happen without the car warning you).

Up here in the Great White North we need 'em a bit more than you will, but they're not particularly needed for starting until well below freezing, and even then the engine is pretty good at generating enough heat to get rolling.

Oh, and I second Oilhammer's "sounds like your coolant temperature sensor is lying". It's an inexpensive part and pretty straightforward to replace so should not be too expensive to have repaired. The car does a great job of finding stuff that has failed... stuff that's lying is a bit more tricky.

 

[scooperhsd]

Ever heard the expression - "If it ain't broke, don't touch it " - well that pretty much applies to the glowplugs , especially you living in East Texas.

 

[CheapBastard]

As well, perhaps you'll be happy to hear that in East Texas your car will do a fine job of starting most if not all year round *without* glowplugs (which as posted above won't happen without the car warning you).
Up here in the Great White North we need 'em a bit more than you will, but they're not particularly needed for starting until well below freezing, and even then the engine is pretty good at generating enough heat to get rolling.
Oh, and I second Oilhammer's "sounds like your coolant temperature sensor is lying". It's an inexpensive part and pretty straightforward to replace so should not be too expensive to have repaired. The car does a great job of finding stuff that has failed... stuff that's lying is a bit more tricky.

For warm weather climates would it be a best practice when starting the engine to still turn the key to the acc. position a few seconds before cranking the starter or is it ok to insert the key and immediately crank the starter?

 

[mjez]

For warm weather climates would it be a best practice when starting the engine to still turn the key to the acc. position a few seconds before cranking the starter or is it ok to insert the key and immediately crank the starter?

I would wait for GP indicator light to go off and then start. If outside temp is warm enough the GP light will go off in less than a second.

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[CatherineL]

Five very helpful responses and so soon! Thank you, everybody. oilhammer mentioned that the coolant temp sensor might not be sending the correct value. I had no idea that a coolant temp sensor sends a value . Coolant temp sensor was replaced in Oct 2018 at 133K. I'm going to take it back to that shop to talk to them about this possibility. Thanks, oilhammer. I'm a little confused about not needing glow plugs in East Texas (Vince Waldon comment). My question would then be: Can this 2006 VW New Beetle TDI be refitted with regular spark plugs? (This could be a very silly question, I realize.) [History of this car: Daughter bought it new in California; later moved to Montana with/it. VW was in MT for nine years, then she drove here to East TX for my use.]

 

[JB05]

In my experience with a GP pilot light, the pre-glow lasts longer than the indicator light on the dash, depending on ambient temperatures.

 

[tadawson]

Five very helpful responses and so soon! Thank you, everybody. oilhammer mentioned that the coolant temp sensor might not be sending the correct value. I had no idea that a coolant temp sensor sends a value . Coolant temp sensor was replaced in Oct 2018 at 133K. I'm going to take it back to that shop to talk to them about this possibility. Thanks, oilhammer. I'm a little confused about not needing glow plugs in East Texas (Vince Waldon comment). My question would then be: Can this 2006 VW New Beetle TDI be refitted with regular spark plugs? (This could be a very silly question, I realize.) [History of this car: Daughter bought it new in California; later moved to Montana with/it. VW was in MT for nine years, then she drove here to East TX for my use.]

Glow plugs are basically heaters that preheat the combustion chambers to assist starting, and serve no purpose once running. When running, heat comes from compression,, and injection timing regulates ignition. Due to that, a spark plug would do nothing other than to add a part not designed for diesel pressures which could blow out . . .

 

[Mongler98]

glow plugs are light light bulbs. change the ones that go bad as they go bad.
in your house, you dont change every light bulb at the same time when one goes bad right? same deal.

 

[Vince Waldon]

For warm weather climates would it be a best practice when starting the engine to still turn the key to the acc. position a few seconds before cranking the starter or is it ok to insert the key and immediately crank the starter?

My best practice... for me... is to do what the people who made the car recommend I do: turn the key to on, wait for the glowplug light to go off, and then start the car.

Has worked for me every single time.

 

[mjez]

My question would then be: Can this 2006 VW New Beetle TDI be refitted with regular spark plugs?[/B] (This could be a very silly question, I realize.)][/QUOTE]

I am speachless right now...

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[JesseTDI]

Five very helpful responses and so soon! Thank you, everybody. oilhammer mentioned that the coolant temp sensor might not be sending the correct value. I had no idea that a coolant temp sensor sends a value . Coolant temp sensor was replaced in Oct 2018 at 133K. I'm going to take it back to that shop to talk to them about this possibility. Thanks, oilhammer. I'm a little confused about not needing glow plugs in East Texas (Vince Waldon comment). My question would then be: Can this 2006 VW New Beetle TDI be refitted with regular spark plugs? (This could be a very silly question, I realize.) [History of this car: Daughter bought it new in California; later moved to Montana with/it. VW was in MT for nine years, then she drove here to East TX for my use.]

Diesel engines dont use spark plugs. They fire off of heat and compression, gasoline engines need a spark to fire. Glow plugs are fitted to diesel engines to provide a little heat so they can fire in extremely cold conditions. In your area of the country you will never "need" the glowplugs it just doesnt get cold enough.

 

[scooperhsd]

Hey guys - to be fair - it can get into the 30's and maybe even the 20's in East Texas , so the Glowplugs may actually get some use .

 

[JETaah]

glow plugs are light light bulbs. change the ones that go bad as they go bad.
in your house, you dont change every light bulb at the same time when one goes bad right? same deal.

Don't know about that.
Everytime one goes out and you replace it, you have to get the Check Engine Light reset with a scan tool. The light does not go out simply by replacing the faulty plug.

If you own the scan tool yourself it is not that big of a deal.
And, for the average owner, they may have to go to a repair facility to get it done for a minimum service/ inspection charge which could be a lot depending on where you go. If the plugs have been in there a long time, get them all changed so that you will know where they stand.

The glow plug fault code on the 2006 New Beetle will point directly to the faulty glow plug...or circuit. Glow plug fault codes generally can not tell if it is due to the glow plug or the harness connection to the plug. ECU just knows that the circuit resistance is not what it should be.

Also, do not rely upon Autozone, etc... to provide the correct glow plugs.
Many chain store will prescribe the same glow plug for vehicles from 1996 to 2006 and it ain't so. Your car has glow plugs that work at a different voltage than the pre-2004 cars and are also software update dependent. You will have to know which software is in your engine computer to get it right. Getting that wrong will produce hard starts in cold weather or over voltage to the wrong plugs.

The proper plugs for your car are not the cheapest out there.

The lastest revision for your car has this VW part number:
N10591609

They are made by NGK.

It is possible that these plugs came in your car from the factory with the latest software to match. Maybe someone else here can verify that.

The ones for a 2006 Jetta TDI are not the same so make sure that you go to a reliable source when the time comes.
One such source is this:
https://www.idparts.com/glow-plug-7v-oem-ngk-ceramic-a4-bewbhw-p-2178.html
BUT...you need to establish which engine computer software is in the car first.


While being in Texas will minimize your starting problems due to glow plugs you would run into problems if you go to Montana on the colder days. Having the right ones in there will help you to forget about them. They will do the job as necessity dictates.

 

[IndigoBlueWagon]

Pay attention to what JETaah said, especially about matching the replacement plugs to the current software in your ECU. You'll probably have to contact a dealer with your VIN and ask them to look at the recall history for the car.

But I'm betting if you fix the coolant temp sensor issue you'll be all set.

 

[Vince Waldon]

I'm betting if you fix the coolant temp sensor issue you'll be all set.

Me too.

 

[Mongler98]

never ceases to amaze me at how uneducated most car owners can be about the very basics of how their possessions operates.
SPARK PLUGS
i died a bit

 

[KiwiCanuck]

never ceases to amaze me at how uneducated most car owners can be about the very basics of how their possessions operates.
SPARK PLUGS
i died a bit

I remember seeing a pickup with a Cummins in it .. the rear window sticker: “REAL TRUCKS DON’T HAVE SPARK PLUGS”
Nor do VW TDIs

 

[IndigoBlueWagon]

Cummins don't have glow plugs!

 

[Mongler98]

That's right. They have a air warmer at the intake between the manifold and the snorkel intake elbow.
My favorite diesel sticker was
"I'd rather be cummin than stroken!

 

[JB05]

I think they, Cummins have a heater coil in the air in-take in place of GP's. Seems I read that somewhere.

 

[Mike_04GolfTDI]

One thing that might be worth doing is removing the glowplugs just to make sure you can remove them. Sometimes they get stuck or gummed up with carbon.

They should screw in and out quite easily, unless they’re stuck.

If you encounter any difficulty removing one, stop and consider if you want to continue. Once it’s already stuck, it can be better to just leave it until you really must remove it for whatever reason.

I would suggest removal and replacement once per year, as a preventative measure against them getting stuck. Make a note of the voltage and part number written on them so you know what to buy when you need to.

Also, what I have done is when one goes bad, replace them all with new ones, and then you have three old spares that you can swap in one at a time as the news ones fail.

 

[Mongler98]

Doing that much work and clearing codes just to put an old one back in service? Just replace the one you need. Spend the money when you need to. Do it when the engine is hot, not cold. Much greater chance to get them off.

 

[tadawson]

I think they, Cummins have a heater coil in the air in-take in place of GP's. Seems I read that somewhere.

A grid heater, correct . . . Located right at the entrance to the intake manifold:

https://i.ebayimg.com/images/g/MqwAAOSw0h9ZtyHl/s-l1600.jpg

 

[CJM_RVA]

I'm going to add a stupid question. I've only had my TDI ('13 JSW) since April of this year. This being my first diesel, I wasn't even aware one was supposed to wait for the glow plug light to go out before engaging the starter. I assume this wouldn't be an issue in spring/summer temperatures in the mid-Atlantic anyway? But probably something I need to pay attention to once actual winter sets in?

(Or, should I say, tell my wife to pay attention to, as now she drives "my" car most days. So much for not liking wagons.)

 

[Mongler98]

I'm going to add a stupid question. I've only had my TDI ('13 JSW) since April of this year. This being my first diesel, I wasn't even aware one was supposed to wait for the glow plug light to go out before engaging the starter. I assume this wouldn't be an issue in spring/summer temperatures in the mid-Atlantic anyway? But probably something I need to pay attention to once actual winter sets in?
(Or, should I say, tell my wife to pay attention to, as now she drives "my" car most days. So much for not liking wagons.)

If your car starts quickly, then no wait was nessasary. It's a good practice to do it anyways though, the light will go off very quickly if it's not needed.

 

[IndigoBlueWagon]

It's a good idea to always wait for the light on a cold start. It lets the glow plug system work properly and reduces strain on the starter and battery.

You (and your wife) might want to take a quick look at the owners manual. You may learn a number of things you didn't know about the car.

 

[scooperhsd]

The common thing is to look for a "pigtail" light and wait until that goes off before engaging the starter, as it was explained above.


Nice thing about the 2015's - they will automatically take care of this for you.

 

[CJM_RVA]

You (and your wife) might want to take a quick look at the owners manual. You may learn a number of things you didn't know about the car.

Not a bad idea at all. I usually do this whenever I buy a car...this one didn't come with a manual and by the time I got around to buying one on eBay, I'd already had it for a couple of months and I guess it didn't seem as essential. (Yes, I know it's available online, but the way one has to access it is kind of a PITA.)

Life is busy, excuses, excuses blah blah blah.