I had this happen when I changed the oil a while back. I put the full 8 quarts in and got almost nothing registering on the dipstick. I let it sit for a while and still nothing... so I added an other quart and it showed up fine. I was perplexed. I ran it like that for a few months and checked it and I was almost two quarts over. So I drained and replaced the oil and the problem did not present again. Weird. I have no sludge. Everything had just been opened and cleaned up with new gaskets. I even accounted for the oil in the filter. I don’t know where it went but that one oil change threw me for a loop and still does.
So weird…I've got a similar problem right now on my FJ62. On Saturday I was driving for a few hours. I filled up gas at the end and I was alarmed to see no oil on the dip stick. I ended up adding 2.5 qts to get it to show full again.
It was about time for an oil change anyway, so I drained the oil and filled with 8qts yesterday with a new (small) filter. After doing that, the oil is way over full, like 1.5 inches above the full line. So now I am siphoning off the oil through the dip stick hole (quite slow but working great). I am about 1.5qts over full. It doesn't make any sense to me.
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This exact scenario happened with me and my friend’s old S type Jaguar on a long road trip.
Our conclusion was:
- Pulled in to gas station and oil level was way low.
- Added 1-1/2 quarts to get oil level to Full line on dipstick then drove the remaining few hundred miles home
- Next morning he checked the oil level and it was way too high.
Checking the oil level immediately after driving a lot will show a lower oil level on the dipstick because a lot of oil is still up in the engine, coating everything and it hasn’t had enough time to drain back into the pan.
Wait several minutes after driving before checking oil level. (I guess).
But missing almost 2 quarts is definitely a head scratcher. Maybe the dipstick wasn’t fully inserted the time it read low?
I’ve thought about drain down time as well. What @OSS said could be true. It’s also possible there is an Obstruction in one of the oil path ways in the engine block. This would explain why so much gets trapped higher up. With extended down time the oil would, maybe, have time to migrate back down to the pan.It's a head scratcher indeed. I was talking to my friend about this "drain down" time. But I don't think it's an issue. When the oil was way low, I checked multiple times as I added the 2.5qts. The oil was hot at that point and should flow down easily.
Just now I did a test:
- Engine was sitting off for 30+ minutes, shows exactly full when measured.
- Ran the engine for a couple minutes to get the oil flowing. Probably around bath water warm oil.
- Turned it off
- Went around to measure as fast as I could.
- Even 30 seconds after the engine was off, the oil was pretty much exactly where it was before turning on the engine. So I don't think drain down time could come even close to 2qts of difference.
When I refreshed all my gaskets I was pleasantly surprised to see how clean the engine was inside. It made me wonder if it had been rebuilt in the past. I have not seen an engine this old with this many miles so clean before. I would be surprised if I have any sludge anywhere, but I certainly wouldn’t rule it out completely. I’m wrong often. I run regular Dino with zinc additive. I tried the synthetic after I replaced all my gaskets and it leaked. I switched back to Dino and it stopped leaking. Don’t understand why to be honest. I just keep a close eye on oil levels and pressure and trust Mr Toyota’s engineering.Hmmm
I think the main drainage from the top of the head is down the upper pushrod holes- then down to the upper lifter ledge behind the push rod side cover - then down -somehow- in there to the pan. (Along the lifter bore? - don’t know)
I never examined closely where the drainage is behind the side cover …
When I removed my push rod side cover - it had a lot of sludge coating it. I had been using synthetic oil for 190,000 miles and changed it regularly, so to see sludge was a surprise since the rest of the engine was sparkly clean.
So if my engine could develop sludge behind the side cover - god only knows what tar slicks exist behind other 2F side covers whose engine has been running on regular Dino oil for decades.
I’ve seen 2F engines’ rocker assemblies completely coated in black sludge, (on this website) so sludge can happen.
And who knows? Maybe some of that gunk can slough off and partially block the drainage behind the side cover.
I don’t know. Maybe it isn’t possible… but maybe it is.
If my 2F engine was reading wonky oil levels that didn’t make sense, I’d remove the side cover and examine what’s going on behind it very carefully.
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