Engine knock

[redbaz]

When starting car up from cold, engine knocks for about 20 seconds any ideas guys?
Car milage is 40,000, when warmed up knock goes.
Car is only used at weekends, and sunny days. Please put my mind at rest!!!
Engine is 3.4cc.

 

[Richard_Hamilton]

If it isn't a heavy knock, and you have good oil pressure, I would suspect a lazy tappet. They sometimes take a while to pump up with oil, especially after a week's inactivity.

I wouldn't worry, but next time you get an oil change, try a 5W-40 oil (if you aren't already using one).

 

[redbaz]

Thanks Richard, oil pressure is spot on, using 5/40 already, sounds more like a piston knock, rather than tappet.

 

[AlexBell]

This is very common on start-up, if your piston was knocking it would be quite serious. []

If the car stands still for more than 4 weeks for example it sounds like the whole thing is coming apart when you start it, my heart stopped beating the first time I heard it...

 

[redbaz]

Thanks Alex thats put my mind at rest

 

[philippe]

It should sound more like a ticking than a knocking sound and in which case it could to be the tappets, I have always experienced this, and had new ones fitted and still the same, lack of use doesn't help.

Cheers Phil