Unexplained slight rise in oil level

Messages
37
Location
TX
After I change the oil in my 17 Tundra, my dipstick usually shows around 7/8 towards the full mark, and shortly after my 45,000 mile change, it also showed somewhere around the 7/8 mark after a new Toyota filter and 8 quarts of Mobil 1 (I even tried to get every drop out of the Mobil 1 containers to see if I could get it closer to the full level), now at around 46,200 miles my oil level is right at the full level. The manual states to wait at least 5 minutes after shutting the vehicle off before checking the level. I've found my best readings are 15 min after shut down or after sitting overnight. Each time I check it, I'm in my garage on level ground. My coolant level appears unchanged since oil change, there is no noticeable smell of fuel on the dipstick, and overall the oil appears perfectly normal. Is it possible for several ounces of oil to get suspended somewhere or hung up and then released at the next drive? I've never sent in a sample to Blackstone, but I've ordered one this time. Anyone else ever experienced any unexplained oil level fluctuation like this?
 
Messages
509
Location
VA
Probably is some fuel dilution going on. I have not experienced this on my 2011 5.7L Tundra but it is one of the reasons I switched over to a 5w-30 oil.
 

Idlewild294

Thread starter
Messages
37
Location
TX
That's my concern, I drive mostly highway miles, but I did idle for an hour or so recently while working on a radio and short tripped it more than usual. Will extended highway driving at 75 mph burn down any excess fuel in the oil? I've read conflicting reports on if fuel can be burned off like condensation can. Also, should I change it sooner than the 5,000 mile interval for this change?
 
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Messages
8,994
Location
Houston, TX
Originally Posted by Idlewild294
That's my concern, I drive mostly highway miles, but I did idle for an hour or so recently while working on a radio and short tripped it more than usual. Will extended highway driving at 75 mph burn down any excess fuel in the oil? I've read conflicting reports on if fuel can be burned off like condensation can. Also, should I change it sooner than the 5,000 mile interval for this change?
A UOA that uses gas chromatography to check for fuel dilution would tell you for sure.
 
Messages
954
Location
Alberta
Fuel dilution is generally from direct injection. Is Toyota's 5.7 direct injection? If not, I would think just normal variance and parking slope or something. 7/8ths or full...to close to all.
 
Messages
34,057
Location
Southern NJ
Originally Posted by tcp71
Fuel dilution is generally from direct injection. Is Toyota's 5.7 direct injection? If not, I would think just normal variance and parking slope or something. 7/8ths or full...to close to all.
That's what I'm thinking. I know in my car it specifically states to wait at least 5 minutes until engine has been shutdown. However, waiting as much as 30-60 minutes will give you a different result than waiting just 5 minutes. Some engines are more finicky.
 
Messages
602
Location
The ATL
I doubt you have a problem. Sounds like too much idling and short tripping. If you can't smell gas in the oil on the dipstick I wouldn't worry about it. These engines aren't direct injected.
 
Messages
100
Location
Raleigh, NC
Originally Posted by Idlewild294
That's my concern, I drive mostly highway miles, but I did idle for an hour or so recently while working on a radio and short tripped it more than usual. Will extended highway driving at 75 mph burn down any excess fuel in the oil? I've read conflicting reports on if fuel can be burned off like condensation can. Also, should I change it sooner than the 5,000 mile interval for this change?
Gasoline boils at 250° ish, so likely not.
 
Messages
602
Location
The ATL
Originally Posted by jqgz
Originally Posted by Idlewild294
That's my concern, I drive mostly highway miles, but I did idle for an hour or so recently while working on a radio and short tripped it more than usual. Will extended highway driving at 75 mph burn down any excess fuel in the oil? I've read conflicting reports on if fuel can be burned off like condensation can. Also, should I change it sooner than the 5,000 mile interval for this change?
Gasoline boils at 250° ish, so likely not.
It doesn't need to boil.
 
Messages
1,084
Location
Pacific Northwest
I suspect that maybe the anti-drain back valve on your oil filter is not sealing well? This would seem to be a higher odds than a sudden increase in fuel dilution.
 
Messages
1,272
Location
Muncie, Indiana
Originally Posted by ripcord
I suspect that maybe the anti-drain back valve on your oil filter is not sealing well? This would seem to be a higher odds than a sudden increase in fuel dilution.
It's a cartridge I'd assume the ADBV would be a permenant part of the filter housing.
 
Messages
2,131
Location
WA
You don't need to go 75mph and get a ticket. shocked2 leave it in S4 or S5 to get the higher RPM. In D, you will quickly end up in 6th. I typically check my oil level a day later and in the same spot and haven't noticed much of increase and/or decrease even with the factory 0W20. However, I rarely short trip my truck as I have two other (commute and a spare) cars. I can see why you are concerned ... but I have noticed some oil level fluctuation with our other cars especially with our only DI car. Tundra is MPFI. The oil doesn't get too hot in this engine and most of them also have oil cooler. The rpm stays very low in D. I wish this car was a 5 spd. I would NEVER buy an 8 spd. or 10 spd. truck! Put in in S4 and go for nice 45 min drive. keep the RPM between 3-4000 and see if it helps. You may come back and say it now went a little below 7/8 and thinking you have a different problem. grin2
 
Messages
35,479
Location
NY
It could be fuel dilution, I'd have a UOA done. I would also park in the garage and do two readings. The first reading, 15 minutes after shut down as you're doing, then another reading after the vehicle sits overnight and compare the levels. There should be no difference, if there is I'd go with the sitting overnight reading.
 
Messages
3,695
Location
Chattanooga, TN
It is fuel, I have it in both my cars. Also, checking oil 15 min after stopping is okay but oil is still hot and not all of it have drained back down. Overnight is the most consistent for me although most people don's care as long as it is between the hash marks and thus, checking at any point is good enough.
 
Messages
1,967
Location
USA
OP, Lets go through some basics to make sure theres a real problem in the first place. When checked- it is parked at the same level and vehicle load? (that affects fill line) Temp- oil expands and increases area just like everything else- are the ambient temps of the oil the same? ( same reason in oil & gas we check tanks under specified conditions- gives false volume readings) Thermal stability is a good thing. Time- make sure settling time is adequate. Takes time for oil to flow and recombine. Sometimes more than others. Dilution- this will almost always happen to a degree but if its chronic it will "keep happening" and the oil level would always be rising because the ratio would always be theoretically increasing because its always adding fuel. Then lets see if there is a problem
 
Messages
425
Location
Daytona Beach
I had an engineer tell me that oil pumps in most engines pump 8 - 12 gallons per minute. If the engine wouldn't drain down at least that fast, there would constantly be oil overflowing the top end. So I doubt that the small amount of "clinging" oil makes that much of a difference on the stick, it might, but it would be small. These days, most dipsticks are sealed air tight by O rings or rubber seals, for emissions purposes of course. I have sometimes noticed a low dipstick reading on the first pull after a drive, but a normal reading on the second check. I'm assuming that the dipstick tube extends below to oil level in the pan to facilitate top side oil changes (Mercedes in particular, 'cause they don't want to fool with the lower cover) thereby trapping air in the dipstick and giving a low reading until the second check. Just my theory. It definitely worked that way on my V6 E350 engine.
 
Messages
1,010
Location
Wash, DC
The oil level in my GDI Hyundai Tucson rises about 1/4" after about 500 miles, then stays put. I rarely drive on the highway more than 25 miles, so I'll have to wait for a road trip to see if the level falls. I always check oil after it sits overnight. When I do an oil change I add enough oil to get it between the add/full lines, then top it off the next day.
 
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