Oil Mystery ....

[gaoverlander]

At 260 k miles I changed the oil in my 95 fzj 80. To quieten the start up rattle you hear on high milage engines I decided to go to Rotella T5 10W 40 instead of the Rotella T5 5W 40 I had been using because I live in Georgia and it's quite hot here with milder winters. I used the OEM skinny oil filter. So it ran fine for a couple days then I began to hear a rattle as if I'm low on oil. I checked the oil level while running and after cleaning the dipstick and inserting then pulling out several times NO OIL shows up ? I shut the engine down go in the house trying to figure out wth is going on because there are no oil leaks and no smoke out of tailpipe either. Also no oil in the coolant or coolant in the oil. I came back out and checked the dipstick again and there it is clean oil right up to the full mark where it should be. I crank her up and within 2-3 minutes its rattling again and it sounds like from the bottom. I check oil while running and its bone dry again ? I repeat process . No oil while running but minutes after shutting down it is full again on dipstick. I thought oil filter is not letting the thicker oil circulate or its clogged . So I change to a bigger higher quality filter and it does the same thing ! How is this possible and what on earth could cause the oil to be trapped on the upper engine while running . I am mechanically and electrically inclined. I am a 49 year old technician who has worked on engines to some degree for 30 years. No mechanic by any means and this one has me stumped guys . Thanks !

 

[flintknapper]

How many qts. of oil did you use when doing the oil change? 7.5-8.0 ?

Why are you checking the oil level with the engine running?

Does your dash gauge show oil pressure as this is happening?

 

[COYS]

Why are you checking the oil level with the engine running?

+1 lol

Also curious as to what he chose as a bigger, higher quality oil filter.

Mine at 250k years young makes zero rattling noises at all times. But it def loves it some Dino juice.

 

[voodu3]

What kind of noise is it making? How’s your power steering pump? A worn out p/s pump gear can sound like your engine is rattling.

 

[Kernal]

"I checked the oil level while running and after cleaning the dipstick and inserting then pulling out several times NO OIL shows up ? I check oil while running and its bone dry again ?"

The oil needs to be checked on a fully warmed up engine when it is off (not running) parked on a level surface. While the engine is running the oil pump is circulating the oil up inside the engine. When the engine is shut off some of that oil will trickle back down into the pan. That explains why nothing shows
up while the engine is running, then reappears once it's shut off.

 

[-Spike-]

Is your oil pressure normal?

 

[gaoverlander]

How many qts. of oil did you use when doing the oil change? 7.5-8.0 ?

Why are you checking the oil level with the engine running?

Does your dash gauge show oil pressure as this is happening?

8 quarts . I checked the oil while running just for a quick reference because of the noise I was hearing . I realize it probably might not be full while running but we are talking BONE DRY ! Clean the stick and check , clean the stick and check . As I tried to make clear I am not mechanically ignorant . I know how to check my oil properly when the engine is warm and at least 3-5 minutes after not running .The dipstick should NOT BE bone dry after 2 minutes running or ever as far as that goes ! I check oil running and shut off warm all the time just to compare that's all. The engine noticeably gets clacking after 2 minutes of running. Starts out smooth. Does anyone have an actual answer as to why the dipstick would be bone dry while running and a solid clear coating of fresh oil at the full mark minutes after shutting down ? Thanks for the comment.

 

[gaoverlander]

The oil pressure is higher than usual . My gauge is crap like most oem 80 oil pressure gauges. Usually It tends to be on the low side until the rpm's are up but during this debacle pressure is up .

 

[mudgudgeon]

You may not be mechanically ignorant, but your missing something mechanically simple.

A full oil change takes 8quarts. From Hi to Low on the stick is approx 1 quart.
With the engine running, I would expect you'd have easily 1 quart circulating throughout the upper engine and galleries.

The length of the dipstick is designed to measure the hot oil when it's drained back to the sump and at rest, not circulating.

This doesn't explain a rattle though

 

[amgraham]

My truck is sitting right in front of me in the shop so for S&Gs I did your procedure... At the full mark while off. Fired it up, pulled the dipstick, wiped it off, dipped it, and it came out bone dry. As a professional mechanic I've never heard of someone checking the oil while running and never tried it myself.

As others said, the dipstick only has access to a quart or so and it definitely has at least that circulating while running. I think your oil levels are totally normal.

If you're really worried about oil pressure check it with a mechanical gauge. Otherwise track down the rattle with a stethoscope or something.

FWIW I am running T6 5W40 with a Toyota small filter and it's been crazy hot here all summer. No rattles, good oil pressure. In fact just did close to 700 miles down to NC and back last weekend running 85 with the AC blasting and it did great.

 

[flintknapper]

As a professional mechanic I've never heard of someone checking the oil while running and never tried it myself.

I just hope he doesn't need to check his fan belts.....

 

[leonard_nemoy]

I once checked the oil on an old Yamaha 4wheeler while it was running and the dipstick got jammed into moving parts of the motor. I don't think its smart to check the oil with an engine running

 

[BILT4ME]

The oil pressure is higher than usual . My gauge is crap like most oem 80 oil pressure gauges. Usually It tends to be on the low side until the rpm's are up but during this debacle pressure is up .

The only possibility is that the oil is being trapped in the valve cover on top of the head and not draining down from the head to the oil pan.

Any recent work done to the top end?

Also, there is typically still oil in the engine, the dipstick doesn't reach that far.

SOMEONE here has probably done it, but I am guessing the even with the engine OFF, the dipstick won't read any oil if there is anything less than 6 qts in the pan.


Looks like @amgraham beat me to it......

 

[jonheld]

This checking the oil thread comes up every few months.

Checking the oil level with a running engine is a waste of time. It tells you nothing.

The sump holds 2 gallons and is internally baffled to keep the pump pickup submerged on steep inclines. You could be 4 quarts low, and it won't care.

Personally, I check oil with a cold engine, before the first start of the day. If I'm anywhere on the dipstick, it's good.

If you have some oil in the engine, and oil pressure with the engine running, you're most likely OK.

 

[Red Merle]

+1 lol

Also curious as to what he chose as a bigger, higher quality oil filter.

Mine at 250k years young makes zero rattling noises at all times. But it def loves it some Dino juice.

What's really better than the Toyota filter unless you can find the original sized one? Bigger doesn't mean better.

 

[Red Merle]

I just hope he doesn't need to check his fan belts.....

Tighten them until they snap and then back off a quarter turn is what I always heard...

 

[shocktower]

I once checked the oil on an old Yamaha 4wheeler while it was running and the dipstick got jammed into moving parts of the motor. I don't think its smart to check the oil with an engine running

Well most motorcycles the dipstick is by the clutch basket, and that is what did yours in a 1FZ there are no moving parts close enough to attack the dipstick

 

[80t0ylc]

..................Personally, I check oil with a cold engine, before the first start of the day. If I'm anywhere on the dipstick, it's good.

If you have some oil in the engine, and oil pressure with the engine running, you're most likely OK.

I have always changed my oil on all my rigs and I used to check the oil this way. Then I read the owner's manuals closely. All of them that I've read say to check it with the engine OFF, on level ground, with the engine warm and to let it set a while (no specifics how long, but I imagine 10 - 30 minutes would be fine). If you check it as @jonheld is suggesting, it should read ABOVE the full mark. How far above varies from rig to rig. If you know the difference in this, it doesn't matter checking cold or warm, but there is a difference and the engine must be off. It does not surprise me in the slightest that the dipstick shows no oil while running. Whatever is left in the oil pan is below the end of the dip stick.

The automatic transmission is checked with engine running and after you've driven it at least 20 minutes. Also you want to cycle the shifter through every position, then back to "Park". Pull dipstick clean it off and return fully, then pull and check. ALL these checks should be done on level ground or the readings will not be accurate. I guess it's possible that the OP is confusing or mentally combining these 2 different procedures.

Edit: Right from my '94 Owner's Manual

 

[COYS]

What's really better than the Toyota filter unless you can find the original sized one? Bigger doesn't mean better.

No idea brotha. I bought a half dozen of those bigger jpn made Campbell’s soup cans, but couldn’t prove to anyone it does a “better job” than the smaller Thai cans available at every toy dealership.

 

[Red Merle]

I have no clue. Thai cans for me. I figure as long as it's filtering something, even if it's only my own diatribe as I swear under my breath in the event of a cheap filter failure, the world is probably better off because of it. So far, so good!