vauxhall meriva

[tamiya]

hi everyone and happy easter to all..... my friend has a vauxhall meriva and it is making a tapping noise from the rocker cover area.also it has a small amount of white mayo sort of thing in the oil filler cap...but no loss of water from the expansion tank etc.it also loses power every now and then and to top it all the speedo goes bonkers when the abs light comes on .....help any ideas ..thanks lee

[AlBags]

That is caused by either poor oil circulation through the hydraulic tappets .. or a worn hydraulic tappet. They hydraulic up when the engine is running, with oil pressure, and take up free play between cam lobe and valve stem tip. This used to be known as valve clearance adjustment.
Try changing the oil and filter, and use a low viscosity grade, as recommended in handbook.
If it does not gradually disappear after engine hot, it would need a strip and replacement of one or more tappets. They are not cheap tho.

[AlBags]

Find out where the speedo gets it's signal from. I doubt it is from same source as the ABS sensor too.
Performance and idle hunting issues: They are known for Mass Air Flow sensor failures (like the Agila/Corsa engines)

[gsr600]

as for the mayo - its a common problem with Vauxhalls, cool running temp -whether its short or long runs.