Question: Using "used" oil for top up oil?

Status
Not open for further replies.
Joined
Aug 27, 2004
Messages
7,628
Location
Katy, Republic of Texas
OK, was reading a thread earlier (THIS ONE) about taking used oil from one engine and using it in another engine to get "full use" out of the oil (although the poster did not care about the life of the engine). I read it and initially did not think much about it, but then it got me thinking (we all know what happens when we do that)
wink.gif


Short version:
Is there anything really wrong with taking gently used xw-20 synthetic oil (that I have clean collected, filtered through something like a coffee filter or such) and using that as a top up oil in another vehicle that uses oil and also requires 5w-20?

Long version:
My truck ('02 F150 5.4L, 130,000 miles on motor) uses 1 qt of oil every 1500 miles (no leaks, new OEM PCV valve, no smoke noticed) and I do a 3k oil change on it because it is mostly a short tripper. I use 5w-20 conventional (Nextgen oil lately, another 1-2 changes left, some blends and HM oils from the stash in the future).

My wifes car ('12 Scion xB, 30,000 miles on the 2.4L 2AZ-FE, uses no oil) gets a change every 5000 miles or 6 months (warranty) and uses xw-20 syn (Pennzoil Platinum, QSUD, Valvoline Syn, all with Wix filters). That oil probably still has life in it, but no longer OCI till warranty over, then probably 7500 miles/annual changes.

Either way, I doubt the oil coming out of her car is in horrible shape, so I was thinking I could use the "old" synthetic oil from the Scion for top up oil for the truck (my last oil change, the Scion's oil came out a clear, dark tan color). Figure I could catch it in a clean jug (let some drain at first, then catch the middle part, let last bit drain into the pan). This would give me at least 2 qts of oil that I could "filter" with something like some coffee filters or such to use as top up oil on the truck. This used oil would only be used another 1500 miles, I think well within it's usefulness. Yes I am being cheap, or environmentally conscious depending on who you ask. Sure I could do a UOA on the Scion oil first, but that is just cost prohibitive and partially defeats the purpose of this (I am cheap).

Anyone ever done this on a regular basis, or am I just crazy to think about it?



(This next part is not a serious question)
To take it to the next step, my truck takes 6 qts, so how about using 1 qt of this "used" synthetic oil with 5 qts of new conventional or syn/blend oil in the truck at the oil change?
 
Truck won't care at the rate it is burning oil anyways.....will be fine. It's going to burn it anyways, and much better than buying that cheap useless oil that the pqia warns us about...
 
come one man, you registered in 2004, I'm sure you read the Mobile2 (mobil1 re-used) threads....
of course you can use it
 
Throw anything into an oil sieve. Skip the coffee filter part.

When lunkheads are down 1-2 quarts of oil I always just throw in old oil, tell 'em it's time for an oil change and pocket any $ they throw me for informing/topping them.

My old oil is vastly better than no oil.

If they're over 2 qts. down I take the time to communicate or even illustrate.
 
I don't know that the coffee filter would even be needed, the oil filter in the Scion should be filtering out the particles unless it has been saturated and gone into bypass. I don't notice any solids in my drained oil other than the dirt and dust that get in my drain pan.

But, I'd agree with the sentiment to buy a cheap conventional for the topoff...although I do think your scheme would be OK, especially given your consumption and short OCIs.
 
How about you just extend you OCI and top-off with fresh, new oil. If you want to be cheap about it, then that is better than doing short OCI and used oil.

Here is the breakdown.

So with 7.5K intervals you will have 6qts of oil for the change and 5qts for the make up. So 11qts every 7.5K

At 3K intervals, you will need 15 quarts (2.5 changes x 6qt per 7.5K miles). So right there you are 4 quarts ahead before makeup. If using 3 new quarts for top-off over 7.5 not including oil changes you are at 18 quarts. So saving 3 quarts in used oil still makes it the wasteful option.

Did I mention less work from crawling under the car?

Those 5.4 can go way longer than 3K miles. I do 5K intervals (based more on hours but 5K is fairly accurate) for my 5.4 used for severe transit work. You can definitely go 7.5K without a bat of the eye. Maybe 10K+ with the make-up.
 
Last edited:
Fear of partially used up oil is vastly overblown. Use it!

Again, I have used Mobil 2 (and even PYB-2, etc.) on a regular basis. Never an issue. Why not? If its good enough to remain in my nice ride for the second half of the OLM interval, its perfectly fine to go in a beater. No need for fancy filtration efforts. Just use care to keep drain pan and funnel clean during transfer.
 
I've been known to dump used (dino) oil in the fuel tank in the F-450 & 6.2 in my sig, only in warm weather, never a higher viscosity than 5W30. Watch out for the blue smoke cloud!!
57.gif
 
Last edited:
Assuming you bought the NextGen on clearance and that you hit AZ for their end of year clearances, I dont understand how filtering and reusing oil is better than paying $1 a quart for fresh?

FYI, with little to no effort, house brand oils can be had for less than $2 at normal pricing.
 
Originally Posted By: dlundblad
Assuming you bought the NextGen on clearance and that you hit AZ for their end of year clearances, I dont understand how filtering and reusing oil is better than paying $1 a quart for fresh?

FYI, with little to no effort, house brand oils can be had for less than $2 at normal pricing.
That's where the clearance NextGen conventional oils went, esp. the bad NOACK 5W20-straight into the IDI diesel's fuel tanks!
 
You may do okay re-using oil. That said, there are some downstides. First, the oil is used. Maybe you know how used it is, maybe not. Second, you don't know if there was any problem with the vehicle in which the car was previously used. Your 130k engine should have a lot of miles left in it, and your oil consumption is neither atypical nor is it unusually high. The price of oil can be pretty inexpensive. Who came up with the idea of putting used oil through a coffee filter. I mean, what is that? BTW, I would consider this question the intellectual equivalent of the "I add so much oil that I don't have to change it." Change the oil and cough up the dough to top up with fresh.
\
 
Status
Not open for further replies.
Back
Top