Six weeks ago, the turbo suddenly blew on my 2005 Volkswagen Touran 1.9 TDI 105bhp. I was shocked by this as Ive always been very regular and frequent about oil changes. I still don't know why it went, but I have fitted a replacement, together with a new cat, and reset up the timing with a new belt and water pump.

Afterwards the car didn't run too well, lacking power, especially at in low gear pulling away and had developed a strange brief 'sucking or blowing' noise when the accelerator was released in excess of 2000rpm. After trying everything I could think of, it when into my local VW agent for diagnostics and work. They had it for three days and told me they couldn't find what was wrong. A clean bill of health from the diagnostics. That waste of time cost me £500.

Since then I changed the boost valve which made no difference, and have removed the cat, which has completely improved the running, but the air noise will not go away. I have pressure tested the air pipes and they seem fine. Also fitted new fuel filter and cleaned out all the pipes etc.

I am now completely out of ideas and would welcome any suggestions on what to try or what might be wrong. I am worried the noise may be related to something which will damage the turbo, or indeed led to its original demise.