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N75 valve

Posted: 05 Jan 2015, 21:56
by scottbott
I want a new one for my passat,have tried GSF and Euro car parts,GSF wanted £98 and Euro £112,looking online they are miles cheaper,any ideas who is best to buy from,the engine is a1.9TDI AFN engine,there seems to so many types and I am not sure which is the right one,thanks

Re: N75 valve

Posted: 05 Jan 2015, 22:15
by lloydy
I'd just buy a genuine one, did on mine.peace of mind then.

Re: N75 valve

Posted: 06 Jan 2015, 08:43
by syncroandy
scottbott wrote:I want a new one for my passat,have tried GSF and Euro car parts,GSF wanted £98 and Euro £112,looking online they are miles cheaper,any ideas who is best to buy from,the engine is a1.9TDI AFN engine,there seems to so many types and I am not sure which is the right one,thanks

Scott, the part number will be marked on your unit. It is almost certainly a 1H0906627A, with the rectangular plug, this is the only one I recollect seeing fitted to AFN Passats. Later cars used a revised version with an oval plug, but which is functionally equivalent. If you want a new unit, genuine Pierburg parts appear to be available in the aftermarket, and may be cheaper than going to VW for the same part.

You might also consider fitting a boost gauge or Scangauge to monitor your inlet air pressure. Probably worth checking all lines/hoses for chafing or cracking. Another distinct possibility for boost problems is the VNT mechanism inside the turbo getting gummed up, the only real solution for this is disassembly and cleaning, or replacement of the turbo.

Re: N75 valve

Posted: 06 Jan 2015, 20:44
by scottbott
i have been looking at an Audi site and people mention about putting Mr muscle in their turbos to clean them out!,anyone here heard of this?

Re: N75 valve

Posted: 06 Jan 2015, 21:00
by lloydy
its meant to work.... First though, remove the clip that holds the actuator arm to the vnt mechanism. Then try to move the vnt mechanism, if it move quite easy, thats not your problem. What makes you think you have a issue with the N75?

Heres a thread i did a while back on how to dismantle and clean the VNT turbo
https://club8090.co.uk/forum/viewtopic.p ... +vnt+turbo" onclick="window.open(this.href);return false;

Re: N75 valve

Posted: 07 Jan 2015, 20:53
by scottbott
in the audi website people had the turbo still fitted to the vehicle and used a thin pipe to feed mr muscle into the turbo and left it for two hours,then started it up Un-Sticking Your TDi VNT Turbo Vanes..... | Audi-Sport.net

Re: N75 valve

Posted: 08 Jan 2015, 07:33
by Aidan
scottbott wrote:in the audi website people had the turbo still fitted to the vehicle and used a thin pipe to feed mr muscle into the turbo and left it for two hours,then started it up Un-Sticking Your TDi VNT Turbo Vanes..... | Audi-Sport.net

and depending on which side of the turbo they put it either sucking the mr muscle through the inlet valves into the combustion chamber and burning it (or not on the first few rotations) or mixing it with the oil or if it damages the seals both - wonder if vaporised mr muscle is good for hot glow plug tips, inlet valve stem seals etc..or is a proven oil additive ?

Re: N75 valve

Posted: 08 Jan 2015, 21:02
by scottbott
they put it into the exhaust side and it just blows out of exhaust on startup

Re: N75 valve

Posted: 08 Jan 2015, 21:15
by lloydy
As I said above, it works. Whether or not it's a good idea is up to the owner of the engine.

Re: N75 valve

Posted: 08 Jan 2015, 21:48
by scottbott
looked at your post about dismantling a turbo,very good,looks a lot easier if the turbo is removed from the vehicle,have bookmarked it for future reference

Re: N75 valve

Posted: 09 Jan 2015, 20:06
by Paul Weeding
The cheap N75 valves you're seeing on line are for the petrol turbo engine...

Nearly fell foul of that myself when looking at sorting a diesel passat :)

Re: N75 valve

Posted: 09 Jan 2015, 20:17
by scottbott
thanks for that,the trouble is car is a 1998,214500 odd miles on it,I just wonder if it is worth spending much on it,it runs fine most of the time,just a pain in the a*** when it goes into limp mode(so to speak)

Re: N75 valve

Posted: 10 Jan 2015, 14:09
by Paul Weeding
If it's only doing it occasionally then likely as not it's the turbo getting sticky... Have you tried running some egr cleaner through it?? :smile:

Re: N75 valve

Posted: 10 Jan 2015, 14:35
by lloydy
ill buy the car for £100! :lol:

Re: N75 valve

Posted: 10 Jan 2015, 15:52
by lloydy
as a simple free test, swap the N75 with the N18. If fault goes away, bingo!