knocking when cold

[kev 1366]

Hi all,

Basically this noise has just started in the last week and this morning was really quite loud so much so that even the wife commented on it.

The engine had a top and bottom end rebuild at 28000k and now has covered 40000mls,when the oil temp gets to about 30'c then it vanishes and seems normal,it doesnt seem to get noisy under load when hot.oil pressure is also ok.

Does it sound like a bottom end issue?

Thanks in advance,

Kev.

[Buffoon]

Did it go back for Tappet adjust and health check after intial running in?

[kev 1366]

yep it went to my main dealer but they didnt do the rebuild,that was done at austec,they just changed a few shims and serviced it as there were no issues at that time,it had its major service last november and i have booked in today for another in a couple of weeks.
When i spoke to the bloke he coulnt shed much light but i think he is just the office guy

kev.

[Far Eastender]

Might be best to go back to Austec.

[JayB]

Sounds to me like piston slap, sort of a dull knocking noise, caused by the piston rocking in the bore when they start to wear. Noisy at start because the forged piston needs to heat up and expand to fit the bore better, hence noise goes as the car warms up.
I think it is a known issue on higher mile sp6 engines due to large short skirted forged pistons, and known bore wear.
If it is that, isn’t burning lots of oil and is holding compression ok, then I wouldn’t have thought it needs an immediate rebuild.
Mine started doing it about 2 years ago, has got very slightly worse, however when hot is ok

J

[kev 1366]

Austec is a bit far to go as i live in york so im sticking with my main dealer this time,as for the piston slack i guess its something to mension when i take it to them,it also is running rough at the mo as has a bit of a misfire which also vanishes when it warms up so not sure if the two things could be related.

thanks for the info guys,

kev.