ZR-1 Net Registry Forums - View Single Post - ZR-1 Oil Change

Great White · 01-24-2025

I've always thought that starting a cold engine before an oil change to "stirr the gunk around" was a silly idea...

If you must do an oil change on an engine that must run before changing the oil (for example to move the vehicle onto a lift,) get the oil up to operating temp first. When I say that, I don't mean idle it up to temp. Starting a cold engine, running it for a few minutes till the coolant has some heat in it, and shutting it back off is pointless. It won't burn off any of the contaminants in the oil! If you are worried about junk in the bottom of the pan, pour a new "chaser" quart of oil in after draining but before you put the plug back in.

Secondly, it takes forever for an LT-5 to 'drain back' after it has ran (I'm not talking about the filter.) This means more used oil will be circulating after the oil change if you don't give it enough time to drain. The engineers clearly didn't want anything starved for oil.

Filling up a filter right before you tip it upside down is counter intuitive. 99% of Mazda wankels have vertically challenged oil filters just like our LT-5. Among the issues they are known for, bearing failure actually isn't one of them. Neither is oil pump failure. Nowhere in any oil change instructions for those engines is there any inclination that the filter must be filled before installing. It doesn't matter in this case. If you want to pre-fill your filter, knock yourself out... Have fun cleaning up the mess afterwards! If you still can't stand it, relocate the filter.

Last... If you really want to do yourself a favor and go the extra mile on your LT-5 oil change, don't forget to drain the cooler. A filter magnet might be a good idea too.

Sorry for writing a book.

01-24-2025	#17
Great White Join Date: Mar 2018 Location: Misery Posts: 82	RE: Run engine before oil change, pre-fill filter? I've always thought that starting a cold engine before an oil change to "stirr the gunk around" was a silly idea... If you must do an oil change on an engine that must run before changing the oil (for example to move the vehicle onto a lift,) get the *oil* up to operating temp first. When I say that, I don't mean idle it up to temp. Starting a cold engine, running it for a few minutes till the coolant has some heat in it, and shutting it back off is pointless. It won't burn off any of the contaminants in the oil! If you are worried about junk in the bottom of the pan, pour a new "chaser" quart of oil in after draining but before you put the plug back in. Secondly, it takes forever for an LT-5 to 'drain back' after it has ran (I'm not talking about the filter.) This means more used oil will be circulating after the oil change if you don't give it enough time to drain. The engineers clearly didn't want anything starved for oil. Filling up a filter right before you tip it upside down is counter intuitive. 99% of Mazda wankels have vertically challenged oil filters just like our LT-5. Among the issues they are known for, bearing failure actually isn't one of them. Neither is oil pump failure. Nowhere in any oil change instructions for those engines is there any inclination that the filter must be filled before installing. It doesn't matter in this case. If you want to pre-fill your filter, knock yourself out... Have fun cleaning up the mess afterwards! If you still can't stand it, relocate the filter. Last... If you really want to do yourself a favor and go the extra mile on your LT-5 oil change, don't forget to drain the cooler. A filter magnet might be a good idea too. Sorry for writing a book.