It would go in...:doh. Also come out as smoke too.
Don't go there, part synthetic 10w40 is what I use upto 15w40 semi synthetic or mineral, any thing by Castrol within that range, depending which is on offer at Tesco or Asda.
5w30 is much too thin, also members recon to stick with mineral or semi, but NEVER full synthetic, and certainly not 5w30
If you want to keep topping the oil up, and have a smoke screen that James Bond would be proud of, then try it..:doh:doh
I would use 15/40 mineral oil, that's what i use i mine, i did use 5/30 synthetic and used about a liter every 150 miles! I though I had serious mechanical issues, changing back to mineral fixed it. I have also used 10/40 with good results :thumb2