I use Renault recommended oil ELF 5W40.....it might be better to use 10W40.
From the last oil change "eat" the engine next 6L.....I think is it too much.
1 and 4 cylinder has less compression than 2 and 3 cylinder.
These two spark plugs were dirty and worked not 100%.
Additionally valve lifters are noisy.
I think is it really the right time to rebuild the engine
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