[Pfeiffer]

I have just swapped my T4 2.5L Petrol engine with a used one that has done 100.000 km less. http://www.vwt4forum.co.uk/showthread.php?t=145102

It has ACU engine and Automatic trasmission.

The 'new' engine has been running fine, but has just developed a tapping sound like the one described many places here, as being problem with vacuum pump - sounds like a dodgy tappet.

The sound is not present when the car is not moving. I can rev the engine and will not hear it.
It is not present if the engine is cold. It gets worse as the engine gets hotter - typically after 20 min drive.
The sound is very present under acceleration and quiet when cruising, as if it has some connection to high torque.
It is not present when braking - either engine braking or with brakes.

Any ideas? The vacuum pump threads seem to apply to diesel engines only, or...?

Thanks

 

[NiSk]

CV joint?

//NiSk

 

[Zmok]

Blowing/Cracked exhaust manifold?

No vac pump on a petrol

 

[Pfeiffer]

I would be surprised if it is CV joint - only happens when car warms up and doesn't change when driving straight/turning etc. And never had any signs of it before the engine swap.

Anyways, I will get the car on a lift this weekend and check.. might have left something loose..

 

[Pfeiffer]

If it helps any others; it was the warm air deflector plate around the exhaust manifold - rusted around the nuts and was therefore rattling.
It is at a very hard to reach place, so I was not able to catch it a first when doing visual/touch inspection.