Probably dumb question

H

healeyneil

Member
 Glasgow, Scotland
How do you know if your Vanos is working ? Seriously. I used to have a Honda S2000 and it was very obvious when the cam timing changed, but I’m never aware of anything like that with mine - an 06 plate 2.5. A much smoother straight 6 obvs. Neil
 
The VANOS adjusts the timing of the intake and exhaust camshafts continuously, based on engine speed and throttle opening, so there is no noticeable “on” or “off”.
 
It’s more a case you’d know if it wasn’t working. It would be very lumpy. You’d get an engine light thrown up too.
 
I overhauled the Vanos on the wife's M54 2,5i. Up to that point I had no idea it wasn't operating properly as the ECU adjusts to compensate to a certain degree.
Once put back together though, after an initial couple of minutes of rough running as the ECU tried to correct itself, it then ran much more smoothly. Over the next 150 miles or so it just got better and better.
My point being that the deterioration is subtle and you may not realise it needed doing until you've done it. Only option being to drive another with the same engine and a fresh vanos as comparison.
 
If your engine is a 2.5i M54 then almost certainly the VANOS will not be working correctly, if at all. The seals in the Vanos will be rock hard/worn out and the bearings may be pretty shot at too. Mine were last year before I rebuilt it, '03 2.5i M54.
If your engine is 2.5i N52 then it's probably fine.
:thumbsup:
 
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