Check your spark plugs!

Hello everyone.

After I read this...

Okay, I understand. Please provide the German text you want me to translate into English. I will only provide the translation.

I read about people having similar problems, so I thought I should check my spark plugs before I run into those issues myself when I try to replace them.

Even on my relatively young tractor (36,000 km), I had to use a really long lever to tighten it, which, considering the ridiculously low torque of 15 Nm, felt like having a V6 TDI engine in a go-kart.
The threads were so corroded in some places that I thought I was loosening a heavily rusted screw - even though the ZyKo is made of aluminum and the spark plugs themselves weren't rusted.

The design is also extremely prone to failure: The sealing surface is located on the bottom, near the combustion chamber, which means the top of the threaded portion is completely exposed to water and dirt, making it vulnerable.
In the Zündkerzenstecker (ZyKo), at least in the AFN version, the thread is recessed, which means that a small accumulation of debris gradually builds up in the air gap above it, around the spark plug.
Once you unscrew the spark plug and remove it, the dirt that has accumulated in the spark plug well will trickle into the cylinder (which the engine will appreciate on the next run ). However, if you verschandeln it out beforehand, for example, laboriously using a wire hook as far as possible, or if you let a few drops of engine oil or similar seep into the gap, the dirt will stick to the spark plug body or at the top of the hole, so that you can wipe it off afterwards.

I can only recommend that everyone, at the next opportunity, removes their spark plugs, cleans the threads of any aluminum buildup, and then lubricates them, for example with copper paste, before re-installing them. This way, you won't experience the same problem as described in the link above when you have to replace the spark plugs due to a defect.

Before you try to remove your stubborn spark plugs with a stuck socket wrench, it's better to disconnect any interfering fuel lines, etc., so that you can work from above, for example, using fixed sockets.
My pipe wrench with a 10x11 mm socket (where 10 mm is for the candle/spark plug) fits perfectly with its 11 mm end into a long 14 mm open-end wrench, allowing me to apply the necessary loosening torque (estimated at around 40 Nm) in a controlled manner.

@Rainer: This is not to say that I consider the technical article about glow plugs, etc., to be finished/unnecessary with this .
... but perhaps some of you might find an hour during your Christmas mini-vacation to check on your car's engine, before the road salt spray starts up again.

Hey Ulf,

Your tips came at just the right time, as I'm going to be working on my glow plugs next week. I actually got these very cheaply (about half the price of the Bosch service) on eBay. I hope that after one heating cycle, the engine will start running on all cylinders. Currently, it needs to be heated up three times before it starts running on only 2-3 cylinders, which then ends after a few seconds in idle. Wishing you a happy holiday season.
Best regards from Bielefeld.

Peter.

hi Peter,
I doubt that the starting behavior of your engine will change. If I'm not mistaken, the Volvo has the same 5-cylinder engine as the T4.
Last winter, my 75kW motor started 'on the first try' every time, even though 4 glow plugs were defective.
At -10°C, I had to engage the starter motor 2-3 times. I'm more inclined to think it's related to the start of fuel injection or the injection timing.
The 10x11 Bauhaus socket wrench with a 14mm socket attachment is actually the best option for expansion. However, it is not necessary to remove the fuel injection lines.
Unfortunately, this task always has to be carried out in the coldest weather. A problem arises because the electrical... Connection cables are very prone to failure and may break.
Best, Jan.

Hi,

I can only recommend using WEICON Anti-Seize lubricant on the threads! This stuff is really good!!! It's definitely a good idea to remove the spark plugs when the engine is warm. Unfortunately, I had bad luck and had to remove the Zyko and have two Helicoils installed. But it's also possible to do it with a fixed head... but be careful not to drill too deep!

Despite the intact threads, aluminum shavings were also found on the piston... well, I was then able to easily remove them .

Best regards, Christian.

@ JanB

Hey Jan,
I'm not entirely sure about that either, but it's working much better now that it's a bit warmer.
The start of injection/injection timing was still within acceptable limits as of the end of September.
I will see it.

@haehnlein,

Hey Christian,
Where can I find this stuff, and what exactly is it?

Greetings from BI.
Peter.

Hello,
You're just trying to shift the blame.
I changed two candles in the fall.
Mileage: 135,000 km. They were installed and removed easily, like butter, and were the first spark plugs (96 AFN).

Best regards, Albrecht.

Albrecht wrote:

Hello, You're just trying to shift the blame. I changed two candles in the fall. Mileage: 135,000 km. They went in and out

like butter and were the first spark plugs (96 AFN).

Hello Albrecht,

Based on other experiences, it seems to me that you were simply lucky (for whatever reason).

If, even occasionally, the threads on the candle housings get stripped when attempting to remove them, I thought it was worth mentioning as a preventative measure.

JanB wrote:

However, removing the fuel injection lines is not necessary.

Hi Jan,

In my AFN engine, spark plug number 4 is located directly beneath the fuel injector line. I can't get the socket wrench onto the spark plug without removing something.

It seems to vary depending on the specific diagnostic code.

roter_Korsar wrote:

Where can I find this stuff, and what exactly is it?

Hi Peter,

"This is a thread sealant paste that is significantly better than copper grease (->higher temperature resistance, doesn't wash out, etc.). It's especially great for threaded connections that are prone to cold welding (e.g., manifolds, glow plugs, exhaust systems)!!" For example, even when using copper grease, I still find that the screws on exhaust connections eventually become rusted and stuck after a while.

You should be able to find anti-seize at any (good) auto parts store. I bought mine in Wiesbaden at Bremsenteile Boller&Co (0611-422031). If anyone lives in the area, you should definitely go there! He gets all Bosch parts, most of the original parts (timing belt, etc.) at top prices (I already get an extra discount as a regular customer )!!!

Best regards, Christian.

Albrecht wrote:

Hello, You're just trying to shift the blame. I changed two candles in the fall. Mileage: 135,000 km. They were installed and removed easily, like butter, and were the first spark plugs (96 AFN).

Hi Albrecht,

The first two spark plugs came out without any problem for me... then came the third cylinder . It was so stuck in that I could only get it to move with enormous torque. After I managed to get it to turn two or three rotations carefully... the spark plug was still stuck in just as deep . Even after several rotations, it still turned with difficulty. And then, on the 4th cylinder, the spark plug turned easily, but it wouldn't come out! I suspect that the spark plugs were screwed in too tightly. Here's the translation:

"It's also worth noting that they were all completely worn out (my father's car has 260,000 km and is still running with its original parts!) -> narrowed rinse gap due to excessive torque!!"

So, to tighten the screws, take the torque wrench in your hand .
A little less than 15 Nm wouldn't hurt!
Best regards, Christian.

I'm probably one of the lucky ones. After my 1Z absorbed a huge amount of water, I had to remove the glow plugs to drain it. This was quite easy with a hand socket wrench. This happened at around 180,000 km and it was the first time. Candles.

Hello,

It wasn't meant like that. I believe what Haehnlein said, that he had a lot of trouble with his glow plugs, and I follow the forum, so I'm aware of it.
Probably, someone had already messed with it before, jammed the glow plug in, and thought, "I'm not going to replace that anymore," and that person was haehnlein then .
I just think it's a bit excessive to remove the glow plugs when nothing is broken, just to check the threads. That sounded a bit extreme to me.
"Don't change a winning team."
If they need to be replaced anyway, it certainly won't hurt to re-install them with copper paste, but that's a general principle.

Best regards, Albrecht.
Best regards, Albrecht.

Albrecht wrote:

I mean, I think it's a bit excessive to remove the glow plugs just to check the threads when nothing is broken; that's what it sounded like to me!

Hi Albrecht,

That's exactly what it was meant to be, as a preventative tip!

If I extrapolate the already existing difficulty in removing two of the spark plugs that were factory-installed, assuming they will eventually fail at around 1xx,000 km, then I can imagine that when trying to remove them, I might have sheared off the upper part while the threads and lower part remained stuck in the cylinder head.

Warm regards regarding the thought - after all, the candle housings are just hollow bodies through which the +connection is guided.

By the way, the two candles didn't just get stuck for a few degrees when loosening; they were stuck all the way until they came out completely, which is why I initially compared them to a rusty screw.

'I also did a spark plug replacement about 8 weeks ago. For me, they actually came out without any problems. The only one that was a little difficult was the one on the 3rd cylinder, but after that, they all came out easily! By the way, Hehnlein's tip about using anti-seize is invaluable. I've been using that stuff for a while now, and I haven't had any more problems with stuck screws or seized threads!'

aaah, another one with damaged glow plug threads:

/viewtopic.php?p=9799#9799

How do you access the links from posts that you are not directly involved in?

Best regards, Christian.

haehnlein wrote:

How do you actually get the link to posts that you are not directly involved in?

Hi Christian,

For me (w98): right-click on it, select "open in a new window", and then the complete link will appear in the website address field.
I can copy and paste that into the post I'm writing using Ctrl+C and Ctrl+V.