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View Full Version : 3.0TDI injector nozzle taper



bluezie
05-02-2024, 08:30 PM
Bit of an odd one, I've just changed the copper seals on my injectors (3.0TDI CDUD) as one was leaking badly, and stinking the car out. That seal had eroded away and was a C profile, the others were still O's but badly eroded, and one other injector had started to blow by.
The odd bit is, all 6 injector nozzles are reverse tapered, ie fatter at the tip. The taper looks almost too perfect for it to be overheating and swelling, as the tapers have straight sides, and are identical on all 6 injectors. The internet says they have had something really bad happen to them, and are knackered, but they work perfectly! The car starts, idles, and drives like a dream, no smoking, no mis-fires or no frequent DPF regenerations.
Having watched on Youtube others changing their injectors, they all seem to be tapered, so are these really odd injectors with tapered nozzles, or is there something inherently wrong with this engine which causes them all to swell at the tip, but still work perfectly?

Crasher
06-02-2024, 04:33 PM
Pictures please.

bluezie
07-02-2024, 01:08 AM
Stupidly I didn't take any, but I'll find some off tinternet

bluezie
07-02-2024, 01:34 AM
I screen shotted a video and tried to post a .png or .jpg picture, but this site won't upload them, so -

Audi VW 3.0 TDI Hissing Ticking Noise Injector Seals Leaking (youtube.com) (https://www.youtube.com/watch?v=0vM3jNzUPoM&t=374s) Go to 9.55, and watch until 12.10 These injectors are exactly the same tapers as mine.

bluezie
07-02-2024, 09:54 AM
I managed to get the jpg to load, but well worth watching the video anyway. As a side note, very odd how one injector is badly eroded right up in the threaded area? I can't see how heat capable of doing that could travel that far up there without the rest of the injector and cylinder head being destroyed, could it be a high pressure fuel leak has cut the metal away?

39359

Crasher
07-02-2024, 02:29 PM
The is gas erosion due to blowby of the seal.

bluezie
07-02-2024, 08:04 PM
The is gas erosion due to blowby of the seal.
Can you elaborate please? What is eroded - is this the cause of tapered nozzles, or just the eroded injector body?
If not the nozzles, any idea what's caused them to be tapered? have you seen tapered nozzles before?

Crasher
08-02-2024, 03:02 PM
They are quite soft metal, the hot combustion gases being forced past the seals dissolve the metal.

Bishop187
21-02-2024, 11:30 AM
Did u fit them injectors back in?


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Crasher
21-02-2024, 04:27 PM
I am just servicing a 2014 4L V6 and the customer reported "smoke on the horizon", opened the bonnet, oil blown all over the left strut and onto the exhaust manifold.

bluezie
21-02-2024, 09:50 PM
Did u fit them injectors back in?


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Yes because- the car starts and runs absolutely perfectly, I don't have around £2,000 lying around for new injectors, and the car is in constant use!
It's only done 90K, so surely they're not totally knackered just yet, the car just had its 10th birthday, so I'm not spending that sort of money on it, if I don't have to, hence the reason for this thread.