Yes, it can leak at the sending unit.
You can use an oil stop-leak product to stop an oil leak on your 2002 Peugeot 206 1.4.
use leak stop or something. Where is your oil leak?
you fix the leak
I wouldn't recommend it. Replace the gasket.
It is at the bottom of the oil pan.
It can leak oil out from the rear of the intake manifold gasket. The oil sending unit is right behind the distributor and it can leak oil too. There is also a gasket that fits on the bottom of the distributor where it goes into the intake that can leak. And the worse thing it could be is the rear main gasket leaking oil and you would have to remove the transmission to repair that.
Yes, it can be harmful. Use no oil treatment or stop leak at all.
Most stop leak additives do nothing but empty your wallet. Replace the gasket that is leaking.
If you have an engine oil leak on your 2002 Peugeot 206 1.4, you can use an oil stop-leak product to fix it.
try castrol oil stabilizer - it will stabilize the oil and reduce the leak.
I drive an F250 with 120,000 mi, heavy loads in bed of truck, and trailer occasionally, and used White Shepherd exactly per instructions on bottle. Leak was moderate to bad with 6" circle of oil after normal operation. The leak has almost completely stopped down to a drop or two a day. I am reapplying with this oil change to completely eliminate leak. Satisfied so far, but first application didn't completely stop it after 4000 miles oil change. Better than it was and I think it will stop after this oil change. Pricey product but looks like it works. G in Texas.