My sister just bought a 1998 Ford Escort ZX-2 with the DOHC 2.0L engine. I read that this car was back-specified to use 5W-20 so I went ahead and bought 5 quarts of Pennzoil 5W-20 along with a Purolator Premium Plus oil filter and I'll be using 5W-20 for the first time. I already had a bunch of 5W-30 but I figured I'd give it a shot, especially since it was on sale. Anyone have any thoughts on using 5W-20 in an older Ford like this? I know it works great in newer vehicles that are specified for it, just debating whether or not I should try it in this older vehicle, even though it was specified for it. Edit: The vehicle has 91,000 miles on it. Doesn't appear to use any oil.