Add between 0.5 - 1.0L of synthetic ATF to the engine oil to help free, quieten hydraulic tappets, revive seals and generally clean the engine.
It's a lot cheaper than the Forte products, can be left in as long as you like and will do as good if not better a job of it.
I've used it in countless vehicles to sort noisy hydraulic tappets, revive oil seals and clean the engine internals. I could sit here typing for hours about the different vehicles i've used it on and i can tell you now, there is about a litre of it in my B280E engine now (even though it doesn't have hydraulic tappets) and about 0.5L in the C27 engine in my Rover 827 (that does have hydraulic tappets and a reputation for being "tappety" - mine isn't!) and i've used it on many previous cars too.
Favourite synthetic ATF for this is Carlube ATF-U which can be used for many Volvo in the gearboxes and is currently in the boxes of both my cars.
