Glow Plugs for 1Z Models

Hello fellow DIY enthusiasts,

Yesterday, I noticed that 2 out of the 4 glow plugs are malfunctioning. This explains why the engine has been harder to start in colder temperatures. Now, my question is: should I just replace the 2 defective ones, or should I replace all 4?

Does anyone have any idea how much these parts cost?

Whether to replace 2 or 4 tires depends on the mileage of your car. If your car has less than 100,000 km, I would consider the two defective tires to be outliers. If your car has more than 100,000 km, I would say it's normal wear and tear, and you should replace all four.

Hi Joerg,

I believe: all four should be replaced! Otherwise, you'll be stuck in the cold winter and have to start all over again. However, it's relatively easy to access the glow plugs on a 1Z engine, so it shouldn't be a problem.

Thank you for the information.

I just replaced all four. The total cost was 71 euros, and it made some extra noise. The replacement went smoothly without any problems!

Okay, I've run into a problem now: the spark plug from the third cylinder (one of the two defective ones) was quite wet. Is this a coincidence, or does it indicate a problem like leaking injectors or something similar? The second defective spark plug was dry, but of course, it was a bit sooty.

ideas? suggestions?

Hi!

71 Euros is a bit much -> for example, dieselsend.de has them for 40 Euros for four!! You're lucky: You got them all. For me, a thread on the infamous 3rd cylinder was broken (now I've been waiting for days for my cylinder head with a Helicoil insert ). If the car has more than 150,000 km, I would proactively replace the 3rd injector (needle lift injector)... it's well known that these things aren't a masterpiece of engineering. I replaced the part for a friend last week -> no more jerking, the engine runs quieter...

Best regards, Christian.

Okay, I'll replace the needle valve. But why is the spark plug wet? On the other hand, the needle valve is probably around 50,000 km old and is actually working. In other words, there's no misfiring or anything like that.

Okay, in that case, I wouldn't change the engine oil! It could be a blown head gasket (although I can't imagine how coolant would get to the spark plug), valve stem seals (but then a lot of oil would have to leak in), or air in the fuel system (which would lead to unburned diesel in the cylinder -> see also the search function: white smoke). Could you describe it in more detail: mileage, short trips before the oil change, etc.?

Best regards, Christian.

Okay, it smells like diesel. No short trips beforehand (distance approximately 50 km), no water loss, no oil loss, no air bubbles in the fuel system, mileage 186000 .

Okay, let's wait and see what the others have to say, but it sounds like it might be an injector nozzle.
In my Passat 1Z with 174,000 km, the ESP drive shaft has more than 1mm of play (the wear limit is 0.3mm!!). During longer periods of inactivity, the suction effect of the fuel lines draws air into the pump (I'm having the ESP rebuilt right now -> new bearings and seal). However, this problem probably only occurs during the cold start phase. If the ESP is also drawing air in while driving... well, that's just a guess -> but if that's the case, it should affect all cylinders?

Best regards, Christian.

It's definitely only the third pot. If I understand your statement correctly, that probably means the nozzle is dripping, right?

I'm not an expert either (I've only been a TDI driver for a short time), but the dripping issue was a problem with older generations with high mileage (I heard that from someone at VW). However, I also read a thread online (I no longer remember the address), which stated that if the injector needle is stuck in the high-pressure pump, the EDC reduces the injection amount in the 3rd cylinder and increases it in the others... I don't know if this results in incomplete combustion .

Best regards, Christian.

joergs wrote:

... Okay, I've run into a problem now: the spark plug from the third cylinder (one of the two defective ones) was quite wet. Is this a coincidence, or does it indicate a problem like leaking injectors or something similar? The second defective spark plug was dry, but of course, it was a bit sooty. ...

... I also discovered the leaking nozzle because of a wet glow plug. Unscrew the nozzle and you'll be sure. If necessary, I can send you a picture of my defective "leaking" nozzle.

haehnlein wrote:

I'm not an expert either (I've only been a TDI driver for a short time), but the dripping issue was a problem with older generations with high mileage (I heard that from someone at VW). However, I also read a thread online (I don't remember the address anymore), which stated that if the injector needle is stuck in the high-pressure pump, the EDC reduces the injection amount in the 3rd cylinder and increases it in the others... I don't know if that results in incomplete combustion. Best regards, Christian

Hi Christian,

Don't believe that the VE TDI is drastically different from the VK diesel. Hanging or dripping injectors can also occur in the VE TDI.
The most important difference is certainly the higher injection pressures of the other cylinder head and the poorer compatibility with alternative fuels (biodiesel or rapeseed oil). The VE pumps are pushed to their maximum here and are therefore somewhat mechanically sensitive (in my opinion).

I took a look at the issue and found nothing in the NHG (presumably a diagnostic system). I then decided to replace the entire set of injectors. It turned out that 2 of the injectors were leaking! Well, the car runs better now, the engine doesn't idle as roughly, and it smells like violets coming from the exhaust again... }

It was quite an expensive undertaking, but it seems to have been worth it! Oh yes, with the new parts, I now need 5.2 liters of oil, whereas before I needed 5.6 liters immediately!

Hi Joerg,

I always say: NOZZLES ARE WEAR PARTS!!!

By the way, in my case, it wasn't the NHG that was leaking.

@bertil:

Sure, nozzles are wear-and-tear parts! I agree!

I already understood that it wasn't the NHG for you! It's just puzzling to me why the candle in the 3rd pot was wet. That's because of the cylinder from the NHG. However, the nozzles on the 2nd and 4th cylinders were actually defective. How strange!

It was a lot of fun getting those injectors out. You have to warm up the cylinder head and use a punch and a chisel. } But they are out now, and the new ones are in, and the car is running like it used to in its best days!!!!! }