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dieselmartin Profi-Schrauber


Joined: 03/13/2003 Posts: 10121 Karma: +29 / -0 Location: in der Werkstatt 2007 Volkswagen Passat Premium Support
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04-01-2004, 22:50 Subject: 1Z Solenoid Valve: No More Clicking Noise |
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Hi.
Yesterday afternoon, when I turned on the ignition (a few degrees below freezing) so I could check the oil level with the headlights on in the garage, it was suspiciously quiet.
The magnetic valve for turbocharger pressure regulation is no longer rattling (otherwise, there's quite a bit of activity going on inside). (My aftermarket control unit always makes it click.)
Only if you got extremely close could you hear a faint clicking sound.
At first, I thought it had finally given up the ghost, but after a (somewhat) difficult engine start, it sputtered back to life.
Could the clicking sound require so much power (high voltage) that the obviously stressed battery could still turn the motor, but not provide enough power for a continuous clicking sound? (I find that hard to believe).
Or is it actually starting to go wrong, and should I invest those 30 euros now just in case, before I have to drive home with a pressure of only 0.6 bar?
m;
Translated on 01-10-2026, 4:59.
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dieselschrauber Administrator


Joined: 04/12/2002 Posts: 18121 Karma: +800 / -0 Location: St.Gallen 2018 Volkswagen T6 
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05-01-2004, 11:29 Subject: 1Z Solenoid Valve: No More Clicking Noise |
Translating... |
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[Translating...] Never touch a running system. |
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dieselmartin Profi-Schrauber


Joined: 03/13/2003 Posts: 10121 Karma: +29 / -0 Location: in der Werkstatt 2007 Volkswagen Passat Premium Support
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05-01-2004, 11:36 Subject: 1Z Solenoid Valve: No More Clicking Noise |
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You mean I shouldn't have even measured the oil  in the first place.
I could buy a valve and always have one "on hand," just in case.
Okay, then I'll just leave the tractor as it is.
m;
Translated on 01-10-2026, 5:00.
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Bertil Profi-Schrauber

Joined: 04/15/2002 Posts: 5628 Karma: +108 / -0
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05-01-2004, 12:48 Subject: 1Z Solenoid Valve: No More Clicking Noise |
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dieselmartin wrote: | Rainer K. wrote: | | Never touch a running system. |
You mean I shouldn't have even measured the oil | in the first place.
.... exactly, just keep going for as long as possible until nothing is left...
Seriously now:
I wouldn't attribute too much significance to the missing sound. With my old 1Z, the valve sometimes didn't click either (it also had the AF control unit). Gruß Bertil
Skoda 5E5 CZDA + Mini R50 W10 + VW ID.3 + Fiat Ducato 250 + 161 DX
*** Technische Anfragen per PN werden von mir nicht beantwortet! ***
Translated on 01-10-2026, 5:03.
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dieselmartin Profi-Schrauber


Joined: 03/13/2003 Posts: 10121 Karma: +29 / -0 Location: in der Werkstatt 2007 Volkswagen Passat Premium Support
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05-01-2004, 13:11 Subject: 1Z Solenoid Valve: No More Clicking Noise |
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Well, it's not really the noise that bothers me.
But the thing was so quiet that I'm sure it not only didn't rattle, but it didn't even turn on!
I suspected it might be frozen moisture or something like that, but then it shouldn't have made a rattling noise after the engine started.
"I need to listen to a 1.4 TDI engine sometime; it also has a wastegate turbocharger and therefore that valve. Is that valve also mounted in the fender well on that one?"
I just don't want it to get stuck in the off position (0.6 bar of boost pressure) or even worse, in the other extreme (boost pressure until it bursts).
Then it's better to replace it proactively and perhaps even get a quieter clicking sound  .
m;
Translated on 01-10-2026, 5:05.
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WarLord Guest
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05-01-2004, 13:18 Subject: 1Z Solenoid Valve: No More Clicking Noise |
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There's no risk of overpressure leading to a failure. Instead, it goes into emergency mode. I'm familiar with this from my 1Z (which frequently goes into emergency mode). By the way, it's normal for the valve to sometimes click and sometimes not (especially when it's very cold). My 1Z and a friend's 1Z both exhibit this behavior. However, thinking about it, recently, especially when it was outside, it frequently went into emergency mode. Although, it also went into emergency mode in the summer. But this morning, it didn't.
Best regards, WarLord.
Translated on 01-10-2026, 5:06.
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dieselmartin Profi-Schrauber


Joined: 03/13/2003 Posts: 10121 Karma: +29 / -0 Location: in der Werkstatt 2007 Volkswagen Passat Premium Support
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05-01-2004, 14:28 Subject: 1Z Solenoid Valve: No More Clicking Noise |
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As I said, not only did it not engage, it also didn't shift (as stated in the VW repair manual, you can tell if it's shifting properly by feeling it with your hand).
The thing was dead until the engine started.
I'm familiar with the differences in click-through rates between summer and winter.
Translated on 01-10-2026, 5:07.
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WarLord Guest
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05-01-2004, 21:43 Subject: 1Z Solenoid Valve: No More Clicking Noise |
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I have no idea if it was the same for me. I didn't try any 'laying on of hands.'
Best regards, WarLord.
Translated on 01-10-2026, 5:08.
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m3_bremse Guest
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06-01-2004, 16:21 Subject: 1Z Solenoid Valve: No More Clicking Noise |
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I consider it normal. I know of 3 cars with the 1z engine. The rattling is present in all of them. It's almost or completely inaudible when it's cold. At higher temperatures, it's quite annoying and loud. Replacing the solenoid valve only provided temporary success. Replacing the control unit with a newer generation, also for the 1z (i.e., the one without an EEPROM, but with flash memory), eliminated the noise. It seems like there might have been a software error. 
Translated on 01-10-2026, 5:08.
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dieselmartin Profi-Schrauber


Joined: 03/13/2003 Posts: 10121 Karma: +29 / -0 Location: in der Werkstatt 2007 Volkswagen Passat Premium Support
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06-01-2004, 16:31 Subject: 1Z Solenoid Valve: No More Clicking Noise |
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@ m3
I have the 028 906 021 AF STG, and it starts making a rattling noise as soon as the ignition is turned on.
My valve is louder when it's cold, which is the opposite of what you're describing.
The 028 906 021 GG (located in the AHU engine by a colleague) only rattles when the engine is actually running.
Therefore, in another thread, I also searched for a reliable MOTOR_LAEUFT_SIGNAL to simply switch off the valve using a relay  .
"With my valve, the rattling and the functioning are IDENTICAL. If it doesn't rattle, it doesn't do anything, which is why the fact that it wasn't rattling shocked me so much."
m;
Translated on 01-10-2026, 5:10.
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m3_bremse Guest
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06-01-2004, 16:47 Subject: 1Z Solenoid Valve: No More Clicking Noise |
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The original part that was installed in the Passat was part number 028 906 021 B. The more modern part has the number 028 906 021 FB. I believe it came from a Vento or Golf. It eliminated the ticking noise when the engine was not running.
Why does the ticking bother you? Sure, it's annoying, but as long as there's no reason to, I wouldn't change anything! As we IT people like to say: 'Never touch a running system.' 
Translated on 01-10-2026, 5:11.
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WarLord Guest
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06-01-2004, 17:29 Subject: 1Z Solenoid Valve: No More Clicking Noise |
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As we IT professionals like to say: Never touch a running system.
Unfortunately, we saw this with Blaster and SQLSlammer.
Best regards, WarLord.
Translated on 01-10-2026, 5:12.
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dieselmartin Profi-Schrauber


Joined: 03/13/2003 Posts: 10121 Karma: +29 / -0 Location: in der Werkstatt 2007 Volkswagen Passat Premium Support
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06-01-2004, 17:42 Subject: 1Z Solenoid Valve: No More Clicking Noise |
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So:
I started this thread because I was disturbed/concerned by the sudden failure of the valve.
The idea of eliminating the ticking sound using a relay patch stems from my "there's gotta be a better way" philosophy.
The tractor has also become quieter with the AFN cover - even though it's actually pointless to put so much effort into it  .
m;
Translated on 01-10-2026, 5:13.
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m3_bremse Guest
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06-01-2004, 17:45 Subject: 1Z Solenoid Valve: No More Clicking Noise |
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As we IT professionals like to say: Never touch a running system.
Unfortunately, we saw this with Blaster and SQLSlammer.
Greetings, WarLord.
'Correct! But a responsible administrator wouldn't have such problems. They would patch their systems promptly and regularly. Ideally, the threat would be addressed before it even reaches that point, and is instead blocked by rules, etc., on the firewall or elsewhere. But enough off-topic discussion, okay?'
Translated on 01-10-2026, 5:14.
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m3_bremse Guest
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06-01-2004, 18:04 Subject: 1Z Solenoid Valve: No More Clicking Noise |
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So:
I started this thread because I was disturbed/concerned by the sudden failure of the valve.
The idea of eliminating the ticking sound using a relay patch stems from my 'there's gotta be a better way' philosophy.
The tractor has also become quieter with the AFN cover - even though it's actually pointless to put so much effort into it  .
m;
I understand. It used to annoy me too sometimes. But as long as the boost pressure values etc. are correct, I don't care about the ticking sound. If you're unlucky, you might just end up making things worse with your 'there's always a better way' philosophy.
'As I always say: measure first, then adjust – otherwise, you might end up having to pay someone else to fix your mistakes.'
Translated on 01-10-2026, 5:15.
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dieselmartin Profi-Schrauber


Joined: 03/13/2003 Posts: 10121 Karma: +29 / -0 Location: in der Werkstatt 2007 Volkswagen Passat Premium Support
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06-01-2004, 18:34 Subject: 1Z Solenoid Valve: No More Clicking Noise |
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I've already measured pretty much everything that can be measured.
I haven't analyzed the data from the last 150 km yet. (There are limitations on the amount of electricity used because the vehicle receives less air when it's running at over 3000 RPM).
LDD looks okay, even though I would have liked to have it earlier - but that's just how it is with a Wastegate Lada  .
m;
Translated on 01-10-2026, 5:17.
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