Should I swich to synthetic?

The Facts:
1) 99 Mercury Sabel.
2) 120k miles.
3) Gets an annual oil change after 10k miles with 5-30 cheap stuff.(at the quick oil change shop)
4) Does not burn or lose a drop in that period.
5) Been doing the oil change as described above for 5 years.

The question:
Is there any reason to change to Mobile 1 or Amsoil?

Or should I keep doing what seems to work?

Thanks for any replies.

With your mileage and since you are happy and have no problems. Don't kick the sleeping dog.

Nope. Save your money and just make sure it gets changed. I use synthetic in my bike so I only have to change oil once a year. Besides.... its only a Mercury

if you don't drive alot of miles per year don't change.

With that kind of mileage, you would be wasting your money. The synthetic is a lot slippery and will start to leak out of your older seals because of that. I have over a hundred thousand on the last four cars/trucks and ran it from the start and never had problems, but putting it in now you may start having major leaks and switching back to reg. oil may stop them again.

As far as the synthetic oil goes, it is great, your mileage will go up and your engine wear down. Starts better at sub zero temps and handles overheating much better than normal oil as well.

But I would just do what you are doing now with that many miles on it. It is about six bucks or more a quart for mobile one now if I recall correctly.

I have a 90 Mustang GT that has had a lot of work done on it. Now the car as per Ford Specs used Mobil 1 synthetic oil since it was built. About 5 years ago on a whim I tried some stuff called Royal Purple with no other change to the car. Well the car has been on a few dyno's since I built it so we put it on one to see. We actually did pick up about 5 hp on a 400 hp vehicle. I also went from about 12 mpg on the highway to 16mpg still as the car had ran for a year with Mobil 1. Now I know oil shouldn't give more HP or MPG but it did and the only thing I can attribute it too is less friction in the engine.

I also built a 1980 Toyota Celica brand new off the lot into a road race car. Well we built 3 engines, 3 transmissions and 3 rear ends for the car. One of my sponsors was Amsoil so off course we used it. Well we campaigned the car in SCCA for the 3 years and never changed the first engine out, though we changed rear ends and transmission to get the proper gearing for a given course. Well after 3 years SCCA wouldn't rules wouldn't all the car to run in the class anymore so I gave the car to my son as a graduation gift. We set it up for the street and he decided to keep the engine we had raced for 3 years and sold the extra stuff. Well he still has the car with over 300K miles on it. He tore the original engine down and is showed 50,000 miles of ware. He put it back together again and his son is now driving it.

go with what works. i do mine on the Taurus (same thing as you have) every 5 though with Valvoline high mileage and it seems to work for me. though i use 5-20 ill be moving to 5-30 soon enough as i am losing oil somehow (aint it just like a ford?)

So you drive 10k between changes on Dino? If it works I can't knock it but I suspect that last couple thousand could be doing a lot of wear and tear on your engine. Just a guess. Dino will break down sooner than synthetic.

I've switched all my vehicles to synthetic. Old and new. I have an old Chevy Silverado with 197k on it's 350 engine. Still running smooth. I switched to synthetic at 155k. No leaks or issues. Same with my 89 Baja 25ft (boat). It has the original 454 engine still in it. I switched it to synthetic (Mobil One) 5 years ago with no issues. The running temp on the boat is 5 to 10 degrees cooler. Less friction. 454's are known to burn oil, and mine was burning some before I switched. It still burns some but much less than when it was running dino. Synthetic has a higher burn temp, and with the engine running cooler I suspect both of those factors help keep the oil from burning as much as it did with dino.

I had heard the rumors that switching to synthetic in an older engine can cause oil leaks ...but that has not held true with any of the old engines I switched over. I mainly switched to synthetic for my convenience. I can run further between changes. So I pay more but change oil less often. I was changing every 4k now I change every 8k. In the long run I save money and time.