oil pump
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2nd Gear
Joined: Aug 2009
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oil pump
Hello, Im having a bit of a problem with my oil pump. After running for maybe 35 to 40 miles I start losing oil pressure. When I stop and check my oil its almost empty. When I let the bike cool down for about an hour, all the oil comes back into to pan and it runs with good pressure for another 35 to 40 miles. any suggestions? BTW its a 2008 Road Glide with a 103
Last edited by texasefain; Aug 23, 2012 at 07:56 PM. Reason: Bike year and model
Stellar HDF Member
Joined: Apr 2009
Posts: 2,191
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Hello, Im having a bit of a problem with my oil pump. After running for maybe 35 to 40 miles I start losing oil pressure. When I stop and check my oil its almost empty. When I let the bike cool down for about an hour, all the oil comes back into to pan and it runs with good pressure for another 35 to 40 miles. any suggestions? BTW its a 2008 Road Glide with a 103
Road Warrior
Joined: Nov 2008
Posts: 1,296
Likes: 3
From: Cheltenham, UK
Difficult to say without knowing the exact volumes - ie what is "almost empty"
For fear of being accused of being a Moco rep, my initial response would be that this is "normal" but I would keep an ear (listening is going to tell you everything you need to know).
To support what I am saying:
Firstly from a pressure perspective. Oil viscosity is highly dependant on temperature. Is it heats up in "thins out" so the resistance to flow through all the galleries goes down with a subsequent drop in pressure. Very well known and documented
From a volume perspective, do not be surprised how much oil is spread around the engine whilst running and how long that oil takes to drain back to the cranckcase.
So, after a period of time the oil level will return to "normal" with the bike not running.
For fear of being accused of being a Moco rep, my initial response would be that this is "normal" but I would keep an ear (listening is going to tell you everything you need to know).
To support what I am saying:
Firstly from a pressure perspective. Oil viscosity is highly dependant on temperature. Is it heats up in "thins out" so the resistance to flow through all the galleries goes down with a subsequent drop in pressure. Very well known and documented
From a volume perspective, do not be surprised how much oil is spread around the engine whilst running and how long that oil takes to drain back to the cranckcase.
So, after a period of time the oil level will return to "normal" with the bike not running.
Road Master
Joined: Jun 2010
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From: Annemasse (border of Geneva-Switzerland) facing Mt-Blanc.
In the 70's the Porsche 911 had both oil level and oil pressure gages; it was scary to see the oil level drop to ZERO during acceleration...
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Road Captain
Joined: Jun 2006
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From: Colorado
Hello, Im having a bit of a problem with my oil pump. After running for maybe 35 to 40 miles I start losing oil pressure. When I stop and check my oil its almost empty. When I let the bike cool down for about an hour, all the oil comes back into to pan and it runs with good pressure for another 35 to 40 miles. any suggestions? BTW its a 2008 Road Glide with a 103
Road Captain
Joined: Oct 2007
Posts: 634
Likes: 8
From: Plum & Nearly
That is not normal....
The oil pump not only pumps, it also evacuates oil from the bottom of the engine cases and returns it to the oil tank.
If you check your oil and there is nothing in the tank, then those 4 quarts are in the engine and that is NOT normal.
Based on your description, it is probably a heat related failure of the Oring seal of the of the pump or a failure of the evacuation side of the pump or a blockage of the return passages back to the tank.
It needs to be looked at!
The oil pump not only pumps, it also evacuates oil from the bottom of the engine cases and returns it to the oil tank.
If you check your oil and there is nothing in the tank, then those 4 quarts are in the engine and that is NOT normal.
Based on your description, it is probably a heat related failure of the Oring seal of the of the pump or a failure of the evacuation side of the pump or a blockage of the return passages back to the tank.
It needs to be looked at!
Last edited by twincam47; Aug 24, 2012 at 07:48 AM.