Oil can't clean and protect well at the same time and it's not spectacular at removing pre-existing deposits. For that something like Auto-RX would be much better suited. If you want to go the quick route for cleaning you'd have to use something like a kerosene soak followed by repeated short interval changes to get the residual gunk out. No doubt modern API SM ILSAC GF-4 oils have come a long way, and dinos in particular. But synth still holds an edge in deposits control and stability in most applications. Not as severe an edge as it once did, but if you want the best, dropping $20 for a 5 qt bottle of Mobil1 at Wal-Mart is an economical way to have just that.
Use Synthetic. Mobil 1 is NOT the best and Lucas SUCKS. Use Royal Purple, Amsoil, or Schaeffer's. You car will get 4% to 5% better economy when you change the whole powertrain and will wear much slower. It costs a little extra up front but believe me you'll be glad you switched everything over.
I was running the Walmart supertech/tech2000 0W30 in my Escort, very impressed with how clean it ran, picked up a couple of mpg with it. It runs about 2/3 the price of "brand name" synthetics here and 2x the price of dino oils. Seems capable of being run on 10-15K changes, so you'd save on it.
I remember The RoadWarrior..To understand who he was, you have to go back to another time..the world was powered by the black fuel & the desert sprouted great cities..Gone now, swept away..two mighty warrior tribes went to war & touched off a blaze which engulfed them all. Without fuel, they were nothing..thundering machines sputtered & stopped..Only those mobile enough to scavenge, brutal enough to pillage would survive. The gangs took over the highways, ready to wage war for a tank of juice
The huge difference between conventional and synthetic has faded. Not so much because synthetics have lesser quality as much as conventionals have gotten better. Engines have gotten better, as well.
To get it out of the way quickly, most "synthetics" you get at Wal-Mart are highly processed conventional oils. Yes, they are better...but the price is too high for me. I change oil in five cars and conventional oils make $en$e to me.
It's hard to find a name brand conventional oil that won't go 5k miles today. Where true synthetics shine is when used by consumers that put a lot of miles on their cars/trucks quickly. A good true synthetic can go 8-10k miles without much trouble. Add the famous Amsoil or equivalent remote filters and that can extend out tremendously. That keeps the user out from under the car every other week doing oil changes.
Where true synthetics shine is their pumpability at very low temps and their ability to live at high temps that break down conventional oils quickly. Most of us don't see either of those extremes, and the low temp pumpability of conventionals is getting better.
The verdict is still out on an gas savings acquired from using a synthetic oil. In my F250SD V10 I did 10k miles each on Quaker State conventional 5w-30 and M1 5w-30 (when it really was a true synthetic). There wasn't a .2mpg difference between the two. Nowhere nearly enough to justify the increased costs. Others have voiced the same results, so it isn't just me. Some costly synthetics have shown themselves to increase horsepower and economy, but I won't pay those prices. True mpgs can be had by using high quality synthetic gear lubes, AT fluid, and MT lubes.
You might see mileage gains from using a thinner weight of a high quality synthetic oil. Some cars can handle it, others might not want to do so. Void where prohibited. I've used the thinnest 5w-30 in my '98 LS1 (Havoline Deposit Shield) and the thickest I could stomach (M1 Truck & SUV 5w-40) and both came back with very similar oil analysis results. I'm sure I got better mpgs from the DS, though I can't quantify it. Using the Tr&SUV 5w-40 made the LS1 feel like it was churning molasses until it got good and warmed up. The same thing with the F250SD V10. Ford said to go to 5w-20 in it. Did it, got reasonable oil analysis results. Mileage increased a bit, but with that thing it doesn't make much difference.
All that said, I'm going to settle on one brand of oil (unless others are on sale) and Pennzoil is the one. Good enough for daily use in all the cars I service, cheap enough where it won't break the bank, and I won't have to worry about all the stuff people agonize over endlessly. My '89 CRX will love it, I'm sure.
I ran Schaeffer's 10-30 18,000 miles on a 1996 tacoma 4 cylinder, with oil analysis, and it performed beautifully. Synthetics are great because they keep viscosity longer and handle heat better but also look for a friction modifier that won't build up in the engine. Schaeffer's is by far the best I've found.