Last post on Dec 17, 2011 at 11:53 AM
You are in the Jeep Liberty and Jeep Liberty Diesel
What is this discussion about?
Jeep Liberty, Engine, SUV
#2 of 11 Re: Oil pressure sending unit? [rickc38]
May 07, 2009 (3:18 am)
I can see two things:
- either the ECU does not change the status of the "at pressure" bit (low probability) and sends an engine malfunction alarm,
- or you may have a leaking check valve (oil filter bypass) that lets the pressurized oil return into the sump via the pump after a few minutes when the engine is not running.
The absence of oil film normally explains the ticking sound of your engine but if you use mineral oil that is at the end of it's life, the engine will produce the same sound. This is a typical 4 stroke lawn mower engine issue: my wife doesn't know there is oil in there, she just pushes the thing
#3 of 11 Re: Oil pressure sending unit? [caribou1]
May 07, 2009 (5:53 am)
No I don't use mineral oil. I always use new oil every 3000. But the check valve idea is a possibility though. But doesn't the check valve bypass the filter when it is clogged when the engine is running? I always use a new filter when I change the oil. Because if it was the sending unit sending an incorrect code wouldn't it signal the MIL light? I'm thinking about getting myself a scan tool and see if any fault codes come up even though the check engine light (MIL) isn't on. Might have something in memory.
#4 of 11 Re: Oil pressure sending unit? [rickc38]
May 07, 2009 (8:40 am)
If you put in series:
sump * pump * check valve-&-filter * engine
when the check valve cancels the filter you may get:
sump * pump * engine
I think the time and pressure needed for the oil to circulate backwards through the filter is long enough to give you a noise free start even after a few hours.
#5 of 11 Re: Oil pressure sending unit? [caribou1]
May 07, 2009 (9:10 am)
Ok that is true but if there is oil available in the filter it should start pumping right away. I mean there are no problems with oil pressure as far as I can tell after the oil is changed just that initial start after I have changed the oil and the pump pumps oil back into the system. That's the reason I tried filling the filter so that crucial time when the filter is filling up is eliminated. I don't know if the bypass will allow oil into the main gallery while the filter is filling up I don't think so.
#6 of 11 Re: Oil pressure sending unit? [rickc38]
May 07, 2009 (10:53 am)
You would be surprised to see the time and initial effort it takes for oil to go through a dry membrane. Once the oil made it's way, it's purely friction. Before penetrating the filter it's a surface tension problem, and oil is repelled.
#7 of 11 Re: Oil pressure sending unit? [caribou1]
Nov 06, 2011 (1:21 pm)
We have a same problem with my Liberty 2005 Renegade ... Can you have resolve your problem ?
#8 of 11 Re: Oil pressure sending unit? [ticaille]
Nov 07, 2011 (3:27 am)
Wow this is an old thread I had to go back and read the other posts from before to remember what was said. We still have the Jeep and it still does the same thing. Its usually when it gets colder it turns the oil light on and I have run 5W30 and 10W30 and it makes no difference light or heavier oil. What I am going to try now is running an engine flush on the next oil change. I am thinking there is sludge in there slowing down the oil coming from the filter into the main gallery. Other than that we are about ready to trade it in and it has over 140,000 miles and we never had any problems with the motor.
#9 of 11 Re: Oil pressure sending unit? [rickc38]
Nov 07, 2011 (6:28 am)
Ok thanks . I want you to keep me if ever you find the problem because we seem to have exactly the same. I am looking for the solution also with my mechanic so I know you care.
#10 of 11 oil light, 2002 liberty limited v6
Dec 02, 2011 (1:48 pm)
I was having problems with the oil light coming on when I was sitting idling, I always kept the oil at the full mark and it was using oil not leaking. I reduced the oil level to 1/2 full on the stick and the light does not come on and is not using any oil now.
#11 of 11 Re: oil light, 2002 liberty limited v6 [gary1938]
Dec 17, 2011 (11:53 am)
I have a 2004 Liberty Renegade. Exactly the same problem - on cold days, cold start, oil light comes on. Shut engine off and restart and light goes off and stays off. Had this problem for years now - but only when cold weather approaches.
Just had mechanic replace oil pressure sensing unit and still have the problem.
Some of you have mentioned a "switch" - is there a switch that bypasses the oil filter on startup to get oil to the engine immediately?
Since the light goes off on an engine restart (every time) I don't worry that much about it - but it is a nuisance.