I'm unsure of why there would be any more leakage with synthetic oil
Oil leakage is a product of defective seals ....not the flow properties of the oil that's leaking.
(a little flustered expression struggling to articulate)...let me try it from the other end ... are you saying that dino oil leaks less because of its poorer flow characteristics during start up?
Let's try point/counter point (lets have an exploring debate - totally healthy with smiles on our faces). Let's explore these statements and critique each one with a point or counter point.
I leak oil ..will synthetic leak more?
Fix the leak ..or live with it. What are your other needs in a lubricant? If you like synthetic so much ..live with the added expense. That is, if your engine/wallet would end up in the plus column ..why not? You are already wasting money by leaking dino ..if it's not doing the job you want what are you gonna do?
But will it leak more?
Why would it? Just because a synthetic oil has superior flow properties at given temperatures ..doesn't mean that it "necessarily" has any superior cleaning abilities. I would rather say that because of their superior temp/flow stability that most synthetics don't form deposits that are typical of other type oils.
But ..won't it want to leak faster?
Why? The volume of oil available to "leak" would be the same. Since most of the time the vehicle will be at operating temperature ..the flow characteristics of either dino or synth will be about the same (practically speaking). Lets take a valve cover leak ..or timing cover leak. Neither are pressurized lubrication environments. Why would a synthetic "want" to leak more? It will pass through the same opening at operating temp no easier than dino (minor distinctions apply).
But I've heard that if you go to synthetics ..your valve seals may start leaking.
This can happen with dino oil too. Again, I don't think that synthetics have any monopoly on cleaning action per se. Their main feature (IMHO) is that they have superior stability over broad ranges of temperature. My 92 Caravan has shot oil seals. When I use Shell el-cheapo ($0.85/qt.) ..they tend to stop leaking unless I'm really hammering it. One oil change with Pennzoil and the thing smokes at every stop light after warm up.
I think that the gap between dino and synth is getting pretty close for those who choose to "match them up" feature for feature. That is (I imagine), that you can find dinos that are just as good as synthetics EXCEPT in the extreme range of operation. I'm sure that someone could make a case that some dinos are SUPERIOR to SOME synthetics depending on the criteria of the comparison.
My view:
Go ahead and switch! You can probably have just as much effect with a variety of dino oils. That is, any negitive effect of synth ..can be stumbled upon with the right (or wrong, as it may be) dino.
Okay ..let's brain storm here. Assault my opinionated conclusions with zeal
Maybe you can
...or maybe
I'm more than willing to
if need be to the superior authority