I put a different viscosity oil on my car than the one it had can this affect it?

i put a quart of 20w-50 oil on my car and the one in the engine is either 10w-30 or 10w-40. can this make a difference on how the oil rises up to the engine and does it become thicker? what happensI put a different viscosity oil on my car than the one it had can this affect it?
Mixing oil viscosities isn't the greatest thing to do but it can be done if you can't find the correct grade ( it's better to have two different oils in the pan as opposed to being too low on oil ). With the heavier oil added, the oil will thicken up a little bit in the oil pan.