The hydraulic lifters do not require adjustment nearly as often as solid lifters.
no unless you change the size of the rods
yes
Doesn't the transit use a tdci with hydraulic tappets?
From the service manual pg 7-1:The engine uses hydraulic tappets that eliminate manual valve adjustments. The hydraulic tappets have de-foaming chambers. Before assembling, fill the chambers with clean engine oil.
To adjust hydraulic tappets, first ensure the engine is cold and remove the valve cover to access the tappets. Rotate the engine to position the piston of the cylinder you're adjusting at top dead center (TDC) on the compression stroke. Using a feeler gauge, check the clearance between the tappet and the rocker arm; if necessary, adjust the tappet by turning the adjustment screw or nut until the correct clearance is achieved. Finally, recheck the clearance and replace the valve cover.
replace the hydraulic tappets in the rocker arms, valves are non adjustable.
Normally loose tappets will cause a ticking sound in the engine. Depending on if you have mechanical or hydraulic tappets you may need to have them replaced or simply adjusted.
To change the hydraulic tappets on a Peugeot 206 1.4 diesel, first, disconnect the battery and remove any components obstructing access to the engine head, such as the intake manifold or camshaft cover. Remove the camshaft by loosening the retaining bolts in the correct sequence to avoid warping. Replace the hydraulic tappets, ensuring they are properly seated, then reassemble the camshaft and other components in reverse order, and reconnect the battery. Finally, check the oil level and bleed the system if necessary.
GET SOME NEW LIFTERS
The Opel Corsa Utility 1.4 2008 Model does not have Tappets but Hydraulic Lifters.
All 1995 engine variants have hydraulic tappets, removing any need for (or even possibility of) valve clearance adjustment.
try an engine flush at the next oil change, but it will most probably require replacement hydraulic lifters (tappets)