Fan raising emissions? **Please help NCT time nearly up**

[newFTOkid]

Hi All

On a previous post where I said I failed the NCT on emissions. So basically as suggested I changed the coolant sensor , Lambda and cat.

Now my mechanic has come back and said the emissions are fine until the fan cuts in and they go haywire again.

Has anyone ever come across this or advise what the heck I should do next?

I think the alternator may be dodgy (could this be connected)

Thanks in advance

[Myfeckin FTO]

Hi All

On a previous post where I said I failed the NCT on emissions. So basically as suggested I changed the coolant sensor , Lambda and cat.

Now my mechanic has come back and said the emissions are fine until the fan cuts in and they go haywire again.

Has anyone ever come across this or advise what the heck I should do next?

I think the alternator may be dodgy (could this be connected)

Thanks in advance

I've never heard of a fan having a significant effect on emissions. There will be slightly more workload on the engine when it kicks in but unlikely to be enough to alter emissions - I would suggest your mechanic may have got it wrong and there is another issue. Perhaps it's happening when your alternator - rather than your fan, is kicking in?

Your alternator may be affecting current to the ignition system which will then be spilling unburnt fuel into your Cats - hence the emissions rising.