Oil visosity -2003 Taurus 3.0 std. 6 cyl



I live in a warm climate ( S.Carolina). Now that the car has 80k miles on it, is it best to switch from 5w-20 as originally recommended to say 5w-30 Castrol syn. blend ? Would this have any negative effect or would it actually be a good idea?


It will yield no benefit, and may have a negative impact on your wallet. The oil specified when the car was new is what you should use for the life of the vehicle.

Can you find any instructions in the owner’s manual to change oil viscosity at a certain mileage? No, of course you can’t because there is no reason to do it. Those ads for “high mileage” motor oil you’ve been reading are MARKETING, and nothing more.


As usual, I agree with McP.

I’d like to add that your ownersssssssssss manual should have a section that recommends oil options for different driving environments. Usually they’re in a simple bar chart format. Refer to that for the proper oil for your car in your driving environment.


I also agree with the above post.

You will end up with little or no difference. You might gain a little engine life (like 0.02%) and I would expect you will see an equally exciting difference in MPG.


Engine oil recommendations are part technical, part business. Ford seems fixed on the 5W20 oils mainly to squeeze the last little bit of EPA test fuel economy out of its vehicles to meet hte CAFE standards and avoid fines. My son has a Mazda (owned by Ford) 3, which has the same requirements. This car is sold all over the world, even in countries where 5W20 is not even available; there it needs the more common viscosities, such as 10W30 or 15W40 in hot countries. This year I had a Ford explorer lease car, and the oil specified for the V6 was different than the V8, 5W20 and 5W30. Th engine requiring 5W30 probally had slightly looser tolrances, and would consume oil with 5W20 on a hot summer day or high engine loads.

I would never tow a heavy load with 5W20 oil, and my advice to my son was to buy 5W20 synthetic, which, at least has a superior viscosity index, and don’t tow anything during the warrnaty period. My advice to Taurus owners would be to buy the best quality 5W20 (preferably synthetic ) during the warranty period, and go for 5W30 after that. Ford’s priorities are:

  1. Maximize corporate fuel mileage and avoid fines
  2. Get most engines past the warranty limit

Your priorities are:

  1. Get the longest life out of your engine
  2. Be able to drive your car under all condition, incuding high heat and heavy loads.


You can get that 5W20 at Wal-Mart in synthetic by Motorcraft and there is nothing wrong with staying with the 5W20.


And as mentioned before, check the owners’ manual.