2002 harley fat boy
When I check my oil I warm it up to operating temp then I idle it for 1 to 2 minutes and shut it off. Some times the ol only shows a little above the fill mark and other times it shows the oil at the full mark. When I look in the fill mark the oil is always pumping so I know its not sumping. How come its doing this? Its a 2002 harley fat boy.with the hydraulic tensoners installed.
When I check my oil I warm it up to operating temp then I idle it for 1 to 2 minutes and shut it off. Some times the ol only shows a little above the fill mark and other times it shows the oil at the full mark. When I look in the fill mark the oil is always pumping so I know its not sumping. How come its doing this? Its a 2002 harley fat boy.with the hydraulic tensoners installed.
When you say, "I warm it up to operating temp", what does that mean? Do you let it idle for a bit, take it for a ride around the block, or drive it for 20 min or more? Do you do basically the same warm up between the two different measurements?
How much of a difference are we talking between the two different measurements?
What recent work have you done? Was it done just prior to you noticing this issue?
How much of a difference are we talking between the two different measurements?
What recent work have you done? Was it done just prior to you noticing this issue?
Softails will drain oil from the tank to the sump between rides; some faster than others. Never check softail oil cold; always at operating temps. Depending on when the oil was checked could explain the different readings. Plenty of softail owners have checked oil cold before a ride, read a quart low, added a quart and had oil puking everywhere a couple of miles down the road because they over filled.
I always ride it until I reach about 210 degrees? Thats as hot as it gets after about 20 to 30 miles. I have an oil cooler on it. Sometimes it goes just above the add mark and other times it goes to 1/2 full. Thats weher I keep it at so it doesnt have blow by.
Last edited by gerald martin; Apr 7, 2025 at 09:45 PM.
I bet you may have answered your own question. Regarding the "Oil cooler," I would bet that is the variable. Sometimes, it drains back, and sometimes, it doesn't.
Since it appears you do the oil level checks properly and consistently the same, that is probably the one item in your system that could give inconsistency.
Since it appears you do the oil level checks properly and consistently the same, that is probably the one item in your system that could give inconsistency.
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If you overfill the tank, the oil will blow out the breather until it gets to the correct level.
On many disticks the full level on the dipstick is too high.
So when the level is at "full" the tank is actually overfilled.
If filled up to that level, the oil will go out the breather until it gets to the correct level.
This is not a theory; thousands of riders have experienced this.
Just keep the level about 1 to 1-1/2 inches below the filler neck (bike vertical).
Last edited by Dan89FLSTC; Apr 8, 2025 at 08:08 AM.
The difference between measurements is 1/2 qt.....
I've never had (noticed) a difference like that, so I have no first hand knowledge of that issue.
I own '01, '03, & '09 Softails. I bought the '03 new, and the others used. None of them have ever done that, at least that I am aware of. I always check my oil at the end of a ride.
None of mine have oil coolers. I have to assume your oil cooler was an add-on. But even with an oil cooler, it won't drain into the Softail oil tank. It would need to go though the scavenge side of the pump while the engine is running, to get back to the oil tank..

Even if you were not using a Twin Cam spec oil filter with an anti drain back valve, the filter would drain after shutdown, back into the oil pump and probably the sump, not the oil tank.

It would seem that in your two minutes of idling before shutting off your engine, there is a difference of 1/2 qt of oil that is being scavenged back into the oil tank. At the moment, I can't think of why that may be happeneing...
Just curious... Why do you let it idle for a couple minutes before shutdown? Do you ride it hard right up to when you are going to shut off the bike?
I have about a 1/2 mile of slow speed driving through my neighborhood to my garage where I shut off the bike. I never leave it idling for no specific reason. Just before I restart it to pull into my garage, I do my oil checks. They are always consistent. If it checks good, and when it's time for the next ride there is no puddle of oil under the bike, I know the same amount of oil is in the engine as when I last checked... I don't recall ever needing to add oil between oil changes.
Hopefully someone will have an answer for you. At the moment I got nothing...
Last edited by hattitude; Apr 8, 2025 at 09:12 AM.
Here is my theory as to why I am suggesting the Oil Cooler. First, I have the exact same bike, but mine is 100% OEM stock, no cooler. My oil level never changes, regardless of how I check it. I am not methodical to the level check like so many of you are. I just check it, and it's where it should be, and that is that. It has never drained down, even after sitting for a couple of months.
OP'r seems to have a method he uses every time he checks the oil level, so I eliminate that as a variable. Next, he has an accessory oil cooler in the system. So I conclude the oil is circulating for that 2 minutes before the shutdown that OP'r uses. Oil has air, it is circulating and actually pulsating while going through the system. The engine shuts down.
Some oil may be hydraulically held in the cooler and could be showing the oil level low. Other times, temperature, time even atmospheric pressures may let that oil in the cooler be at a minimum amount during the flow, and hence, more oil is back in the tank.
There are my 2 cents on it. I could be completely full of hewy,,,, It happened once, I think, not really sure...
But in turbine engines, we always do a 2-minute G/I before shutdown to stabilize oils and temps.
Yes, I know this is not a turbine engine, but the same procedure is not a bad one to use.
Throw it out the window, or give it some thought - it's just an opinion, and we know what that means.
OP'r seems to have a method he uses every time he checks the oil level, so I eliminate that as a variable. Next, he has an accessory oil cooler in the system. So I conclude the oil is circulating for that 2 minutes before the shutdown that OP'r uses. Oil has air, it is circulating and actually pulsating while going through the system. The engine shuts down.
Some oil may be hydraulically held in the cooler and could be showing the oil level low. Other times, temperature, time even atmospheric pressures may let that oil in the cooler be at a minimum amount during the flow, and hence, more oil is back in the tank.
There are my 2 cents on it. I could be completely full of hewy,,,, It happened once, I think, not really sure...
But in turbine engines, we always do a 2-minute G/I before shutdown to stabilize oils and temps.
Yes, I know this is not a turbine engine, but the same procedure is not a bad one to use.
Throw it out the window, or give it some thought - it's just an opinion, and we know what that means.
Last edited by MarlinSpike; Apr 8, 2025 at 10:43 AM.

















