Dear Tom and Ray:

I found a larger oil filter for my car with the same exact specs, except for the length. The larger one is about 1.5 inches longer. With the extra size and more oil capacity, is there any reason not to use the larger one? My car usually takes a Purolator PSL14670. The bigger one is a PSL30001. Thanks.

-- Larry

RAY: I don't really recommend it, Larry.

TOM: We do that for some customers' cars at the garage, at their request. There's never anything wrong with the filter that comes with the car; it's designed to do the job. But with a larger filter, where everything else is equal, you'll filter a little more oil per minute, and some people think that helps the engine over time.

RAY: You'll increase your oil capacity by a very small amount, so you'll have to add more oil when you refill the crankcase. But if you pay attention to the "Full" mark on the dipstick, that's not a problem.

TOM: But there are two potential dangers I can think of. One is that your new, larger oil filter does not filter to the same specifications as the OEM part (Original Equipment Manufacturer ... the part that came with the car). A lot of filters look the same, but just because it looks the same and screws onto your engine block, that doesn't mean it'll do what the manufacturer requires it to do.

RAY: The other danger is that on some cars, the filter is in a place where if you make it longer, it can get hit by road debris. That's a potential disaster. If something on the road were to strike the filter and tear it open, you'd lose all your oil in a matter of seconds, and your engine likely would be toast.

TOM: So if you're uncertain about any of these things, we suggest that you stick with the manufacturer's recommendation for the oil filter. That's 100 percent adequate, and is guaranteed to do the job.

RAY: But if you're a hobbyist or tinkerer or it's Saturday and you already cleaned the barbecue grill twice, and you know what you're doing, you can try this, Larry.

TOM: You might want to wait until the car is out of warranty first, though. Just in case.