tappits on my 2.5

[drifter]

hello.got a e36 2.5 and got a loudish tapping noise which randomly starts and stops whilst driving.think its the tappits but not sure wat they are,what they do,how much they are and where i can get them from.iv been told there serious so can someone help???

[C Sean Watts]

Do some checking under the hood and in the owner's manual and tell us if it has a "VANOS" camshaft on the intake side.

Also, can it be described as a 'diesel engine sound' or like marbles being shaken in a tin can?

Tappets are also called 'lifters.' They sit between the cam lobes and tops of the valve stems. If the noise is one or more bad tappets, they will need to be replaced. More likely candidate is the VANOS if you have one.

[dayc]

m50 has hydrolic tappets.
use an engine flush and refill with new oil.

[96_323]

Id just check the oil level first, noisy tappets can be a sign of low oil. If it doesnt sort it out then make sure your using the right viscousity oil when you do an oil change.

[ellnic]

My M51 makes a slight tapping noise - AFAIK it's the injectors cracking off. Usual IDI Diesel noise.

As C Sean Watts said - unless it sounds like Marbles in a tin can, it may be usual for an old IDI Derv.

[96_323]

ellinic
A diesel will normally be noisier than a petrol.
A diesel uses the heat of compression to initiate ignition to burn the fuel as opposed to a petrol engine which uses air/fuel followed by a spark by the spark plug.
Basically its compression ignition instead of spark ignition.
Thats only old diesels though, newer diesels are better designed and only sound like diesels when idling, When motoring along at even low revs they are fairly hard to tell.