engine oil question

[GTi Guy]

i know you guys already spoke about this in 2 other threads... but i have another question... my SRM recommends 5W 30.... but i have a gallon castrol full synthetic 5W-50 just sitting there (i won it in a promotion n&m had back in my peugeot days) just wondering if it would be safe to use and not hinder any performance... model is a 2.0R (dohc 2.0 non turbo srm and owners manual say that uses the same oil as turbo models)

[Big Z]

If its just one oil change, it wont be much of an issue.
You may find the engine a little bit lazier and fuel consumption will be a small bit higher, and early morning cold starts may be a small bit harder.

I say mix it 50/50 with some 10W30