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Dear Car Talk: I have a Ford Explorer Sport with an Eco-Boost engine that is approaching the 90,000-mile service. I have changed the oil every 7,500 miles, and most of the time, they sucked up the old oil through the dip stick tube.
My question is, at 90,000 miles, is it a good idea to have the mechanic drop the oil pan for a good cleaning? — Mike
No. Not a good idea, Mike.
This isn’t like a spring cleaning in your house, where you’ve been using a broom for six months, and it finally occurs to you it’s time to actually scrub the used chewing gum off the floor.
There are several reasons not to do this. First of all, it’s a big job to drop the oil pan. So, it’s expensive. It also might create a problem that you don’t currently have. Someone might strip the bolts when reinstalling the pan or pinch the seal and create a leak.
The second reason not to drop the pan is that it’s not necessary. Lots of people think, “Well, there’s sludge sitting at the bottom of the pan, and I should remove it.”
But generally speaking, if you’ve changed your oil regularly, there shouldn’t be any sludge at the bottom of the pan. In the old days, engines were much dirtier and would build up carbon deposits and crud. But we rarely see that anymore, especially in engines that use synthetic oil and have been regularly maintained.
And more importantly, if there is sludge at the bottom of the pan, it’s going to stay there. So, just leave it. The oil pick-up tube won’t suck up crud from the bottom of the pan. It’ll suck up the liquid oil above it.
If you really feel the need to do something more than change the oil, find a mechanic who will remove the drain plug in the pan and drain out your old oil. He can even pour a quart of clean oil in there after it’s drained, to push out anything that might still be on the bottom of the pan — probably nothing.
Just hope he doesn’t strip the oil plug when putting it back in or under-tighten it, so it falls out when you’re driving. That’s why most oil changes are done via tube these days, Mike.
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