Glow plug maintenance

Reposted here hoping to get more views and response.

Car is a 2014 TDI Jetta Sportwagen.


On my previous ride, a 1983 Mercedes-Benz 300CD I pulled the glow plugs every Fall, inspected, tested and reamed the seats. I now have a 2014 TDI and the manuals I have say nothing about preventive maintenance for the glow plugs.
My question is: Do the glow plugs in this engine need the same sort of attention? On the Benz, if you let the plug maintenance go too long the build-up of carbon on the tips made pulling them very difficult.

Leave them alone. They don't require regular maintenance and you may cause issues trying to remove and replace them every year. Some years were ceramic and subject to cracking and breaking easily.

I would not touch them unless you know they are not working. They are extremely sensitive and torque at about 8 foot-pounds. In other words, you probably will need a torque wrench that converts into inch-pounds.

On a side note, my 1984 Mercedes 300D is at about 90K miles on the last glow plugs I put in. I haven't bothered looking at them since putting them in. This is however in Southern California I only use them for the first cold start in the morning.

h.ubk

They are literally almost identical to a lightbulb (filament syle)
You dont change then until they go bad right? Do you maintenance light bulbs when they are still working?
Literally change only the ones that fail, if they fail.
Usually they last a very very long time

Do you really want to spend every year $500 on 4 glow plugs on that car ?
Those GP will set check engine for Pressure sensor before GP go bad, so you will get warning when they go bad.

The engine controller checks them all the time. Leave 'em be.

Thanks all. I am very happy to leave them alone.

It was one of the more PITA things to do on the Benz but if you leave them alone too long on that engine, the build-up of carbon on the tip makes it difficult to impossible to withdraw from the prechamber.

I bought the TDI to minimize my preventive maintenance load and am pleased whenever you tell me NOT to do something.

oilhammer, pleased to see you back in harness. Work is usually the best remedy.

Actually I would remove them once and put anti-seize on them, then leave them alone.

Curious Chris said:

Actually I would remove them once and put anti-seize on them, then leave them alone.

Click to expand...

I would not.
Antiseeze is good for the right application. Problem is, here it is not.
Both the copper and the silver dry up over time and end up gluing them in place. Also it decreases the torque needed to install them. So if you insist on using its use 5% to 8% less torque or your going to strip or deform things. The best thing you can do is put a tiny but of silicone grease on the last bit of the threads closest to the base, not the tip. This will not increase the clamping pressure and will also keep the threads from getting moisture in them

Mongler98 said:

I would not.
Antiseeze is good for the right application. Problem is, here it is not.
Both the copper and the silver dry up over time and end up gluing them in place. Also it decreases the torque needed to install them. So if you insist on using its use 5% to 8% less torque or your going to strip or deform things. The best thing you can do is put a tiny but of silicone grease on the last bit of the threads closest to the base, not the tip. This will not increase the clamping pressure and will also keep the threads from getting moisture in them

Click to expand...

Good advice

I've seen thread sealant used on temp sensors. Sounds good for water oil leakage, right? It can eliminate the ground, something the sensors need. I wouldn't think the anti seize would do that but torque yes.

Ice always put a slight dab of anti seize on the plugs. As of now I’ve not had any problems with them. The one time I did have a problem was the factory plug very early on in my ownership. The thing was squeaking and creaking as I loosened it. I was real nervous it would break as I slowly worked it out or the threads were coming with it. Now I spray the plug with kroil. Start the engine. Then they usually come out. I have one to change in my wife’s car this week. Since writing this message, I’m sure this one will stick in the head and break off.

The CR plugs are VERY different than the VE and PD plugs. They are much more fragile, much more expensive (as they have the integral cylinder pressure sensor). They are also much more "protected" in their placement on the engine, and they are down inside a bit of a tube in the head cuddled up behind and under the intake manifold. They are not exposed on the side of the head like the others.

Some manufacturers even state if any of these new ceramic pressure sensing plugs get removed for ANY reason, they are to be replaced, regardless.

oilhammer said:

The CR plugs are VERY different than the VE and PD plugs. They are much more fragile, much more expensive (as they have the integral cylinder pressure sensor). They are also much more "protected" in their placement on the engine, and they are down inside a bit of a tube in the head cuddled up behind and under the intake manifold. They are not exposed on the side of the head like the others.

Some manufacturers even state if any of these new ceramic pressure sensing plugs get removed for ANY reason, they are to be replaced, regardless.

Click to expand...

I read somewhere the CJAA had 2 glow plug/pressure sensors & 2 non pressure. Any truth in that?

Nope, they are all four the same.

I'm working on a CJAA on the bench right now. Those gp's make me worry. the customers tend to leave them in for me to try. One set took nearly and hour to remove, as I sweated bullets.

These came out just fine, but I agree, don't mess if you don't have to.

I wonder why the Germans do this relief in the top of the hole. It's just a place for things to get in and cause havoc. Same with the older gp's, there is a drop into the gp hole before the threads start. For me, that's just a place for water to stand and corrosion to form.

The 2-stage injectors going back to '96... same thing. The hole does not keep out water or especially, SALT water... road salts.The reaction of the steel of the injector against the aluminum of the head creates aluminum oxide...an ingredient of sand paper... which can make the injector nearly impossible to remove.

I'm testing a small o-ring for the 2-stage injectors that goes between the nozzle nut and the body of the injector. I think it probably will help. It's a snug fit into the injector bore. Maybe it's unnecessary, but the gp's in the common rail seem to have a similar issue, although maybe in a more protected area.

Franko6 said:

I wonder why the Germans do this relief in the top of the hole. It's just a place for things to get in and cause havoc. Same with the older gp's, there is a drop into the gp hole before the threads start. For me, that's just a place for water to stand and corrosion to form.

Click to expand...

This bit caught my eye - is this "drop-in" accessible when the plugs are in? Wondering if it could be filled with a nice marine-grade grease after installing the plugs to create a seal of sorts against the water? Might also eventually wick into the threads too, come to think of it, and make the plugs easier to remove...