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Old 27th May 2013, 01:19   #31
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Default Re: 6 months old VW Polo: 2 breakdowns, 2 parts replaced. Edit: Pics of fuel leak.

Quote:
Originally Posted by leylander View Post
though this reply is very late this could be the root cause for your diesel leak.

there is a PRV(pr. relief valve) present in your rail. the PRV can open because of many logics (issues in the engine), it is done inorder to protect the engine. since the PRV operates mechanically, the ECU of the vehicle ensures there will be a sudden spike in pr. in the rail(approx 1800 bar) so that the PRV can open. when it opens pr. will come down to 750 bar approx. this sudden spike would have resulted in diesel getting leaked out of the connecting pipes to the injectors from the rail if they were misaligned during assembly.

this is one possible issue for diesel getting leaked not during the engine testing or your vehicle running properly so long properly because this would be the 1st time that your PRV would have opened.
Thank you very much for your response.

I have a few questions, please don't think I'm challenging you but merely out of curiosity.

1) If there was a misalignment since assembly (manf defect ?) how come its alright for a few months and starts acting up later on ?

2) Do you think the "able" technicians at VW workshops are competent enough to fix this ?

3) Could this also be the reason for diesel leak near the fuel pump ?
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Old 27th May 2013, 10:24   #32
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Default Re: 6 months old VW Polo: 2 breakdowns, 2 parts replaced. Edit: Pics of fuel leak.

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Originally Posted by shashank.nk View Post
Thank you very much for your response.

I have a few questions, please don't think I'm challenging you but merely out of curiosity.

1) If there was a misalignment since assembly (manf defect ?) how come its alright for a few months and starts acting up later on ?

Generally when there is a minor misalignment, since you are tightening with the bolt there is every possibility that there is no fuel leak in the system under normal running since the pressure that develops in the rail is limited and the misalighnment would have been able to withstand that pressure (generally approx 1400 bar limiting). but when this PRV wants to open (this could again be because of several other reasons), the pr. that is required to open this PRV goes upto 1900 bar, then the misaligned pipes would not have been able to withstand such a load thereby resulting in leak.


2) Do you think the "able" technicians at VW workshops are competent enough to fix this ?

Definetly the guys at the workshop would be able to fix this. all they would have done is loosen the bolt completely, place the connecting pipe properly aligned in its seat and then tighten the bolt.

3) Could this also be the reason for diesel leak near the fuel pump ?
the high pr. line starts right at the end of pump, till the injectors. so if there had been a misalignment leak could have occured at any of this region
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Old 17th December 2014, 12:50   #33
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Default Re: 6 months old VW Polo: 2 breakdowns, 2 parts replaced. Edit: Pics of fuel leak.

Hey Shashank, how is the Polo doing? Have you got rid of it? I too am looking to get a Polo 1.2 MPi but I am quite worried about the durability and reliability as we don't intend to change it for 8 years or so.
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