Oil consumption early vs. late in OCI

Status
Not open for further replies.
Joined
Feb 10, 2015
Messages
234
Location
Maryland, USA
I have a 2007 Camry LE 4 cylinder with the 2AZ-FE engine at about 80,000 miles. As is common with these engines, mine consumes a slight bit of oil. From my estimates, it is about 0.3 or 0.4 quarts per 1,000 miles average. I purchased the car when it had 60,000 miles on it and since that time I have run Pennzoil Platinum 0W-20 in it at about 5,000 mile OCIs. I ran the shorter 5k OCIs with the intent of cleaning out the engine a little, knowing that PP has a pretty good detergent package.

Anyhoo, life got in the way of my last OCI and I let it go to about 6,100 miles. I noticed that the engine seemed to consume noticeably less oil in the later portion of the OCI (between 4,000 and 6,000 miles) than in the earlier. At the beginning of the OCI I filled the oil to the high mark on the dipstick, then I kept a few notes about when I needed to top it off, and they are as follows (according to the manual, the low and high marks on the dipstick represent a difference of 1.2 quarts):

o 2,963.3 miles since last OCI - Topped off oil to just above high mark on dipstick. Dipstick reading at lowest marker. Added 1.2 quarts. (0.4 quarts/1,000 miles consumption average)

o 3,918.0 miles since last OCI - Topped off oil to approximately 0.25 quarts above high mark on dipstick. Burned around 0.5 quarts since last top off. (0.5 quarts/1,000 miles consumption average)

o 6,114.8 miles since last OCI - Burned around 0.3 to 0.5 quarts since last top off. (0.15 to 0.2.5 quarts/1,000 miles consumption average)

I changed the oil at 6,114.8 miles. I realize this didn't exactly follow the scientific method of research, but it did it seem to indicate that the engine consumed less towards the end of the OCI. Now I am trying to determine what could be the reason. The car is a daily driver, mainly about 40 miles each day on the highway with some stop and go depending on backups/accidents/etc. The only difference in that schedule is that in the beginning of the first 3,000 miles she went on two 350 mile all-highway trips (700 open highway miles). The same also happened after the 4,000 mile top off (700 open highway miles). I'm pretty sure that had something to do with it, but why would she consume less oil running non-stop at 70+ MPH on the highway? Wouldn't the constant heat and friction result in increased consumption? One other variable that I am interested in is that I overfilled a bit at 4,000 miles. Could that have resulted in decreased consumption for some reason?

I'm rather curious for anyone else's insight/personal experience/etc. into these observations or changes in oil consumption in general.
 
My experience was the opposite. Consumption would increase toward the end of the OCI with the few oil burners I had experience with. Maybe your oil is thickening up a bit toward the end of the OCI. A UOA would be helpful in determining if that's the case.
 
There is a recall TSB for some of the engines in those years due to oil consumption at the pistons. Perhaps as the oil fouls with contaminants its thickening, not sure. But i do know changing brands seems to cause that.

IMO thats too thin. Don't go below 5w30 in that engine.
 
The AZ is an interesting case - as I understand things it's an aluminum block with cast iron sleeves.
Several of the big time oil consumers are engines without the sleeve (not Toyota) so counting on a "smart process" to protect the bore.
When built correctly - the all aluminum blocks run for 300k or more - but have always wondered where quantity vs quality kicks in when process dependence is in play.
 
The sleeveless blocks are treated with a silicon based process to harden the bore. It it wasn't done correctly, or there was an overheat condition condition the coating can be damaged. With iron sleeves heat transfer is reduced but the liners last the way an iron block would. One suggestion is that low tension piston rings, to reduce friction, contribute to oil consumption for which there is no cure but to change the rings. But, the obvious causes such as PCV valve malfunction or (harder to fix) worn valve guides or seals should be checked before tearing the engine down to get to the rings. Sometimes a slow leak from a part of the system under pressure will be the cause, the leak only shows up when the engine is running so it may not show up in your driveway. You should look under the car for traces.
As I recall the 07 I 4 is rated in the states for 0 W 20 (although the V6 from that year is rated for 5W 30) but it would be interesting to see what oil is specified for the engine in other markets, such as Australia. I don't think 5W 30 would hurt your engine but you probably won't see any difference in consumption. THe acceptable rate from many car makers seems to be a quart per thousand.
 
Status
Not open for further replies.
Back
Top