New clutch slipping

[gabico]

Hi
I changed the clutch on the car about 9 months ago together with the pressure plate and release bearing. The clutch was from a Mitsubishi dealer in uk. Just after the mechanic changed I noticed that it was slipping a bit at high rpms but after a couple of weeks it stopped and it worked fine.
Now I had a guy coming to test drive the car on Thursday and it started to slip again at around 3-4k rpms but not all the time. The guy pressed the acceleration more than I usually do but I had other people testing the car hard before and the clutch was fine.
I took the car to the same mechanic on Friday and he said it can only be a faulty clutch but he needs to test it more. I left the car in the garage and took it back in the evening. I didnt have a chance to talk with the mechanic so I didnt know what he did but the car seemed fine Saturday. But today I noticed again that it is slipping. It seems to only happens in 3rd/4th and not all the time.
Any ideas what could be wrong..Could it really be a faulty clutch? Or maybe it wasnt installed properly?
Thanks

[d_dan]

.

[gabico]

I don't know the condition of the flywheel.I just gave the mechanic the clutch, I hope he would have noticed if there was anything wrong in there...

[gabico]

Went to the mechanic again this morning but the car its driving fine so there was nothing he can do...Said to come back when its slipping again. Asked him about the flywheel and he said it looked ok.
Ill take it for another test at lunch time.

[d_dan]

.

[gabico]

I didnt see any fluids under the car..Anyway the car is with at another mechanic now, and hopefully hell get it sorted soon.

[kevinod]

Qualified mechanic should know better than I would, but when was your clutch fluid changed last?

Maybe check for any signs of leaks around the clutch master cylinder (see 1st workshop doc section 21).

Also, you mentioned he had left the pedal very high while the clutch was bedding in, did he adjust that back again now it's been running a few weeks?

[gabico]

Mystery solved: The gearbox oil seal (the one towards the clutch) was leaking oil on the clutch causing it to slip.
So a new seal and a new clutch and the car drives perfect again.. Thanks