5W-20 to 10w-30?

sittingduck · 10-11-2007, 11:10 AM

i have taurus 2003 and it takes 5w-20 oil, but my machanic told me that when my car has high mileage i should start using heavier oil. is this true?

jfjohn · 10-11-2007, 12:47 PM

I never went higher on the oil, even at 132k. if it's not burning oil, I'd probably stay right where it said from the beginning. you will get worse gas mileage if you go to the heavier oil.

jonmark1985 · 10-11-2007, 02:28 PM

Its somewhat true, usually you have other problems is you start to need it. Also high viscosity oil can cause oil pump cavitation, can break the oil pump shaft, ruins gas mileage, and can make the car's starter work harder in the winter. If you have 200,000 plus miles, or the motor makes noise i wouldn't switch to the heavier weight.

jfjohn · 10-11-2007, 03:09 PM

I would say that maybe some areas of the engine that have experienced a lot of wear could benefit from the higher weight oil but the problem is that other parts of the engine could have little wear and be harmed by the heavier weight just like the guy above me is saying.

sittingduck · 10-11-2007, 04:05 PM

thanks everyone for the advice. I think I'll stay with the original 5-20

jfjohn · 10-11-2007, 10:05 PM

good choice. I would use synthetic. the stuff more than pays for itself in gas mileage savings alone.

JBTaurus03 · 10-18-2007, 08:07 AM

Hi sittingduck, Anything with oil catches my eye. I'm old school being around engines for over 35 years and I still believe viscosity is king. In my 2003 Taurus being in New England I us oil appropriate for the climate. For summer I use HD30 straight wt., fall and spring 10W-30 and winter 5W-30. My advise is to stay away from 5W-20. It just doesn't have enough viscosity, especially after it has a couple of thousand miles on it. I've seen quite a few early engine failures due to spun bearing from people using it. The only reason manufactures have gone to it is to ever so slightly increase the milage of their CAFE fleet. I don't think you would even notice a difference between 5W-20 and 5W-30 for milage. I don't believe that 10W-30 or HD30 would cause any "pump cavitation" or "break oil pump shafts" if used for the proper climate. Heavier oils like 10W-30 and HD30 have a heavier base stock petrolium oil and protect better and hold up longer. As for synthetics - I use to be a big fan of them, but with all the improvement in petroleum oils in the last 20-30 years I feel they are less justifable. If you have a new engine I do believe in after break-in switching to pure synthetic (5W-30). If the engine has more than about 10K miles on it just stick to semi-synthetic or regular oil. I know many will tell you of safely switching at much much higher milage, but then there are many others who did and encountered problems! One of my best friend runs a huge fleet of Town Cars in Florida. He us to use Mobil 1 synthetic and complained that all his engines were very noisy. Two years ago I recommended that he switch to HD30 for nine moths and 10W-30 for Dec, Jan, Feb. He says that was the best thing he ever did! All his cars run so much better, oil last longer (HD30) and the engines are totally quiet. He logs veh milage and says his fleet mileage actually as improved. Well enough said. My two cents, stick with 10W-30 for most driving and 5W-30 for winter. Good luck, JBTaurus03
PS- Car manufactures have derated the life expetency of their motors using 5W-20 by about 30%. Check out the web site Bob Is The Oil Guy to research everything on oils.