Reuse engine oil in the engine?

[mechman600]

There is no harm in reusing low mileage oil. We do it all the time in my shop, although we are dealing with 15L diesels that have 12 gallons of oil, which can get pricey!

[user removed]

Originally Posted by sarguy01

It was still clear. It only had 11,000 miles on it. I think the manual says to change it every 100,000-120,000 miles, but can't remember exactly.

I know what the parts cost and I can rebuild it myself. The 7th Gen Civic's are known to have their inputs bearings fail. The input bearing race is plastic. Mine is on it's way out. When I changed the transmission fluid out at around 95,000 miles, there were some plastic pieces that came out. When I drained that fluid at 106,000 miles, more plastic came out. I put the old fluid back in and topped it off with some fresh fluid. I can hear the "can of marbles" sound in first gear, which means the input bearing is already at some level of failure. The trans still works so I am in no rush to fix it. By the way, a bearing kit is $150 and a synchro set is $200. If the input bearing goes, I may just go for an HX transmission and refresh it before it goes in the car.

If Honda thinks that fluid can stay in the transmission for over 100,000 miles, it should not be a problem to reuse newer fluid, as long as it was kept clean.

Having had a Nissan transmission disintegrate on me on a 200 yard test drive and the customer imply that after 130k miles, it was my fault that the transmission failed, I can speak from experience.

If you continue to drive with obvious impending bearing failure, you will end up with a transmission that can not be rebuilt without replacing a lot more than just bearings. As the bearing fails the shaft becomes misaligned and all sorts of consequential damage is happening which will either make the rebuild a failure or you will end up with noisy gear interface from altered wear patterns, or it couldfail completely.

Just advice from experience, worth exactly what you paid for it.

regards
Mech

[sarguy01]

Originally Posted by Old Mechanic

Having had a Nissan transmission disintegrate on me on a 200 yard test drive and the customer imply that after 130k miles, it was my fault that the transmission failed, I can speak from experience.

If you continue to drive with obvious impending bearing failure, you will end up with a transmission that can not be rebuilt without replacing a lot more than just bearings. As the bearing fails the shaft becomes misaligned and all sorts of consequential damage is happening which will either make the rebuild a failure or you will end up with noisy gear interface from altered wear patterns, or it couldfail completely.

Just advice from experience, worth exactly what you paid for it.

regards
Mech

I know. I should replace it. But, at least I know if it fails, it's my fault!

Honestly, the can of marbles sound isn't that loud. I don't think the transmission is to the point that it is rounding out the transmission case or causing the shafts to misalign. There are plenty of people on various Civic forums that have this issue that didn't end up with failed transmissions. But, that's not to say mine won't fail.

I really don't want to drop the transmission on the car. I was going to replace the bearing when the clutch goes, but that might take a while.

[Frank Lee]

Looks like Mobil 1 synth is $6-10/qt and you'd be dropping 4-5 quarts for a cost of $24-$50. I'd clean the area around the drain and use a clean pan to collect it, then after the repairs filter it back into the engine through a t-shirt or maybe a coffee filter in a large funnel. I suppose you could use the TP or paper towels but I think I'd want to use a funnel with a screen in it in case the paper would rupture.

Or I'd wait until it's oil change time to do the repairs.

[Cobb]

If you are going to reuse it Id use a coffee filter to filter it.

If we were talking antifreeze you can measure its ph and decide if you want to reuse it. I had used walmart brand antifreeze and year later I had rust. Flushed went to peak brand. Year later its clean.

[tvbd56]

My tacoma takes 5.5L of oil and I'll re-use 0.5L of the old oil to save myself from buying a fresh qt and keeping it until the next oil change. But I'll inspect the oil to see if there is anything bad in the oil that I can notice with my own eye before I do so. No complaints here, she's still running strong

[markweatherill]

If you left the oil in the engine, it would still be good for however long your oil change interval is.
So draining it out and putting it back should have no effect, if you can keep it clean. It just isn't a thing that is usually done, hence the 'natural' reaction is to think of drained oil as the same stuff that comes out at regular oil changes.

[oil pan 4]

Hey if the oil only has 1,400 miles on it and you can put it in a nice clean container and keep it clean why not?
Keeping it clean is the only problem I see.

[gone-ot]

I'd invest in a GOOD quality OIL filter and *strain* all the oil thru it before using the oil again...just to be cautious.