How long between synthetic oil changes?
Driver School Candidate
Joined: Jul 2011
Posts: 16
Likes: 1
IMO, changing synthetic oil @ 3k is a waste of resources, money and oil. 3k change intervals were set up back when gas had lead deposits and engines didn't burn as clean. Conventional oils nowadays can handle 5k. Of course the dealer, oil companies, auto parts will tell you less to sell more product ans service. But ask a real(unbiased) mechanic and they will. I've been using 0w30 Amsoil signature and changing at 15k since day 1. Wix filter change at 7500 miles. Have had no issues on 06' Rx400 (that just got paid off by the way!) at all with the engine, and oil still comes out clean. 82K miles on it now and the only problem i've had has come from the VSC computer totally unrelated to mechanical/engine. I'd suggest if anything, increase to 6k just to save on wasting oil, of if you insist in changing every 3k, buy conventional oil. Save resources. Donate the extra 3 bucks/quart to starving kids/church/schools/whatever.
Lead Lap
Joined: Jun 2009
Posts: 668
Likes: 11
From: Ontario
CL Community Team
Joined: Apr 2007
Posts: 12,397
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From: GA
Driver
Joined: Sep 2010
Posts: 123
Likes: 1
From: Ca
Advanced
Joined: Aug 2002
Posts: 619
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From: Colorado, USA
I say judgment is to be made within those OCI's aforementioned. What I don't get is why would people waste time on a tedious and troubled lab test on a TBN number when it can be guesstimated? The due date is guaranteed by the manufacturers to protect your car engine in the range of 6k/12k for synthetic/synthetic extended life oil in a normal everyday driving condition... Give or take a few hundred miles on the lower and middle end if you want to be safe.
I don't think a TBN is required; however, a basic UOA to determine how the oil is doing isn't a bad idea. Early on our RX330, I used Mobil 1 5W30 and after 7,500 miles, it was spent. I did another UOA using Pennzoil Platinum and at 5,000, it was still doing fine. So, I determined my oil change based upon the UOA's.
As for changing based on the color of the oil, I personally think Quaker State makes a lot of sense:
Myth: Oil Color
You can tell the condition of oil by the look, smell or color of it. And if it turns dark or black quickly, it’s no good.
Fact:
Nothing could be further from the truth. If the oil is doing its job of cleaning the engine, then it should be dirty when it is drained. Quaker State® motor oil will start looking dirty a short time after it is put to use. In the case of diesel engines, the oil may look dirty within a few hours of operation. These are signs that the motor oil is doing its job of keeping soot, dirt and other combustion contaminants in suspension to be carried to the filter or removed from the crankcase when the oil is changed. Quaker State motor oils have been formulated to hold these contaminants in suspension until they can be removed with an oil and filter change.
Last edited by cdnewton; Aug 3, 2011 at 06:33 PM.
Lead Lap
Joined: Jun 2009
Posts: 668
Likes: 11
From: Ontario
I say judgment is to be made within those OCI's aforementioned. What I don't get is why would people waste time on a tedious and troubled lab test on a TBN number when it can be guesstimated? The due date is guaranteed by the manufacturers to protect your car engine in the range of 6k/12k for synthetic/synthetic extended life oil in a normal everyday driving condition... Give or take a few hundred miles on the lower and middle end if you want to be safe.
"OCI's is 6000-8000 miles for synthetic oil, even for the ones that label extended life. period!"
Now, are you "guesstimating" 6 to 12 k, or eyeballing the colour
, and someone else here is smelling their oil 
Really, I don't see how a UOA is tedious or troubled (unless you work in the lab and are the one doing the test), since all you do is sample and mail/drop off at the lab. Then if you've run your oil for 10000 miles and the TBN is good and the wear metals are good, and you're comfortable with that mileage, stick with it. No smelling or tasting or feeling or deciding if turd brown is too brown to keep the oil in the car.
CL Community Team
Joined: Apr 2007
Posts: 12,397
Likes: 453
From: GA
CL Community Team
Joined: Apr 2007
Posts: 12,397
Likes: 453
From: GA
And yet, a couple posts before this one you said this..
"OCI's is 6000-8000 miles for synthetic oil, even for the ones that label extended life. period!"
Now, are you "guesstimating" 6 to 12 k, or eyeballing the colour, and someone else here is smelling their oil
Really, I don't see how a UOA is tedious or troubled (unless you work in the lab and are the one doing the test), since all you do is sample and mail/drop off at the lab. Then if you've run your oil for 10000 miles and the TBN is good and the wear metals are good, and you're comfortable with that mileage, stick with it. No smelling or tasting or feeling or deciding if turd brown is too brown to keep the oil in the car.
"OCI's is 6000-8000 miles for synthetic oil, even for the ones that label extended life. period!"
Now, are you "guesstimating" 6 to 12 k, or eyeballing the colour
, and someone else here is smelling their oil Really, I don't see how a UOA is tedious or troubled (unless you work in the lab and are the one doing the test), since all you do is sample and mail/drop off at the lab. Then if you've run your oil for 10000 miles and the TBN is good and the wear metals are good, and you're comfortable with that mileage, stick with it. No smelling or tasting or feeling or deciding if turd brown is too brown to keep the oil in the car.
Driver
Joined: Sep 2010
Posts: 123
Likes: 1
From: Ca
Not everyone is going to send their little oil sample to some lab for a TBN oil analysis. I certainly not. lol The aim is to generally change it every 5.5k,6k, 6.5, 7.5k, 8k, blah to be within the standard of every engine run. You cannot tell me that your last engine run of 10K mile with a good TBN will be the same for the next. After all, it is your money and way of doing things so be it. 