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How To: Oil Pressure Sensor (Sending Unit) for 2.7L (2G)

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 PostPosted: Thu Feb 01, 2007 2:37 am   
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Well, I finally decided to replace the Oil Pressure Sending Unit as I was getting tired of the light being on during my commute and it had started to get much worse this week (was staying on up to 1500+ RPM once the engine warmed up).

There are several threads on the subject of the somewhat infamous Oil Pressure Sensor or Sending Unit. Most of them focus on the 1st Gen versions, but not too much has been detailed on the 2nd Gen. So here it is...(Please forgive my somewhat oily working area...I still have an oil leak to deal with on the oil pan)

Necessary Tools:

3/8" Ratchet
15mm socket
Short 3/8" socket extension
Channel lock pliers (or adjustable wrench bigger than 19mm)
Some flexibility to reach the location - sheesh


Remove passenger side front tire (Not necessary, but might add some working room)
Jack up the passenger side of the car and put the car on jack stands
Remove the forward inner liner behind the passenger side front tire for access.

Steps (Refer to this gallery for photos):

1. Locate the Oil Pressure Sending Unit Cover which is above and to the left of the Oil Filter when looking at the engine from below and behind.
See photo -
[ img ]

2. Remove the Oil Pressure Sending Unit Cover by removing three bolts using the ratchet and 15mm socket. (Use the extension as required)
See photo -
[ img ]

3. Disconnect the electrical connector from the Oil Pressure Sending Unit by sliding the yellow tab to the side and then press the connector locking tab to release it.

4. Remove the Oil Pressure Sending Unit using the Channel locks (have a rag available as this will allow some oil to drip once the unit is removed)
You should now have these parts removed -
[ img ]

5. Carefully install the new sensor making sure to not overtighten (ensure the sensor threads have thread sealant or lock-tight on them)
It should look like this photo when done -
[ img ]

6. Re-attach the electrical connector after cleaning off any oil on the contacts. (Very important to clean the mating contacts)
Should look like this when done -
[ img ]

7. Re-attach Oil Pressure Sending Unit Cover using the three bolts previously removed in step 2.

8. Re-install the forward inner liner which was removed in the prep steps and re-install the tire if removed

9. Lower the car from the jack

10. Test drive long enough to get engine warm to verify problem is repaired. :wink:

This is what the old sensor looked like -
[ img ]

I hope this helps some of the other owners of early 2nd Gens that are starting to experience this problem. By the way, we have the exact same sensor as the 1st Gens, so it isn't a matter of if, but when it will happen to us. :roll:

Note: Restored links to photos 06-06-2008.

Last edited by singindh on Fri Jun 06, 2008 12:18 pm, edited 2 times in total.

 PostPosted: Thu Feb 01, 2007 10:23 pm   

Joined: Wed Dec 01, 2004 2:15 am
Posts: 11623
Location: Calera, Alabama

Great writeup. Pictures helped a lot. Two thoughts though if you don't mind. I'd suggest using thread compound or plumbing teflon tape rather than the loc-tite. The 3/8" NPT pipe thread that is on this sensor needs something "substantial" to complete the seal of the threads against each other. Loc-tite, at least the kind I've used, is too thin and fluid to really do the job right, IMHO.

Second thought, I believe you are correct in the "when" area too. Especially since it's the same sensor and similar mounting places. On the 1g it sits atop the filter adapter, very close to the front exhaust manifold, so it's getting baked all the time. And plastic doesn't like baking ;)

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 PostPosted: Fri Feb 02, 2007 10:41 am   
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To be honest with you, now that I have driven it a couple of days, mine seems to still have a problem too. The light went away right off and didn't come back until the first time I ran it for more than an hour. Now it is coming on anytime the car idle drops to around 600RPM after warming up for about 20-30 minutes. I suspect the residual oil in the mating connector may be the problem, but it may also be the connecting wire is starting to break down from heat. Of course, the only other thing to cause this is that the Oil Pump is actually failing and well...$$$$$$$$

So let's all keep our fingers crossed that it turns out to be one of the less expensive solutions. I will keep everyone posted as I work through the issue.

BTW, the sensor comes with a thread sealant on it if you get it from the dealer. They run about $20...

 PostPosted: Fri Feb 02, 2007 10:12 pm   

Joined: Wed Dec 01, 2004 2:15 am
Posts: 11623
Location: Calera, Alabama

When I replaced mine I used a spray-on electronic contact cleaner to rinse the oil off the electrical connector on the wiring harness. Mine worked fine for about 2 or 3 days and then began lighting up again although not as often. But after about 3 weeks, I haven't seen the oil light on unless the engine is off. ;)

You may still have some oil on the plug from the repair, you could have a drip that just happens to hit it or you may have had a bad sensor. Keep after it. I doubt it's anything more critical than the sensor. Especially if you haven't heard ugly noises out of the engine by now. :twisted:

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 PostPosted: Sun Feb 11, 2007 12:00 am   
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I replaced mine and it worked for about two months before comong back on. I switched to 10w-40 and its not flickering anymore.

There ought to be a better solution.

 PostPosted: Tue Mar 20, 2007 10:51 am   
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Well, a month and a half (+one oil change) later. The light seems to have finally stopped coming on. It slowly started to come on less frequently and then only intermittently when the engine was completely up to temp. Then I had the oil changed last week and now it hasn't come on since. :D
(After watching this occur, I think I could have expedited this process by using a contact cleaning solvent when I replaced the sensor...FYI)

By the way...still using Mobil 1 5W-30.

An interesting note...the shop noticed the mileage on my car (121K + miles) and must have a note about the 2.7L because they mentioned that they thought the engine was sludging and that it needed a flush. :nono:
I promptly went over and inspected the old oil filter and the oil filler opening...not even a hint of sludge. :shock: :)
So I politely declined the offer for the flush by informing them that the engine has run the last 110K + miles on full synthetic with regular oil changes. 8)

This was one of the few times I had taken my car in for a service when it was fairly dirty...think that made them think she wasn't well taken care of? Hmmmmmmm.....

 PostPosted: Tue Mar 20, 2007 11:58 am   
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Joined: Sat Dec 15, 2001 9:00 pm
Posts: 7650
Location: Plano, TX
singindh wrote:
This was one of the few times I had taken my car in for a service when it was fairly dirty...think that made them think she wasn't well taken care of? Hmmmmmmm.....

Yes, dirt in and on the car means dirt in the engine, didn't you know that? :rofl:

Why look at the engine when we can just sell you a service you don't need?

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 PostPosted: Thu May 03, 2007 12:33 am   
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Update...still no light and the oil leak is not as bad as it was. Need to see about an oil pan gasket replacement to finish off the oil leak problem. Have to do the brakes first, though... :roll:

Never stops once you get past 120K miles...

 PostPosted: Sun May 18, 2008 9:05 pm   
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Joined: Fri Nov 03, 2006 9:26 pm
Posts: 666
Location: Quantico, Virginia
Only differance on these instructions for a 2.5 is that there is no cover on the unit, and you need a deep 1 1/16 socket as the switch is a bit hard to get to using channel locks. The one from Harbor Freight is to shallow. I got my socket at Advance auto. The sender unit I got there came with teflon tape on it. I would not use thread lock. It is a bit to "permanent".
Also, I blew out the old plug with air as it had alot of oil in it. This could easily cause the new unit to
fail prematurely.

 PostPosted: Sat Oct 11, 2008 5:40 pm   
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Did this job today on my car after viewing this post and had a few clarifications that might help someone else
. The hardest part was getting the wire connector plug loose. I hate those electrical connectors I never seem to know which way to pinch or push or twist or pull, they all seem different. After sliding the yellow tab I used a small screw driver to pry up in the area of the plastic lock and it slid right off, after 20 minutes of pinching and pulling!!
Total cost of repairs $27.00, $12.00 oil pressure sending unit ( they call it a switch ? ) $8.00 1 1/16 “ deep socket, $7.00 CRC Electrical Connector Cleaner.
There was no exterior oil leaking but when I got it out I could see oil on the connector and in the sending unit. I guess I got to it fairly soon after it started leaking.
The new unit had sealer on the threads and I also used some Teflon tape.
It made it easer to turn the ratchet and get it on the plug with a short universal extension (U joint). The electrical connector cleaner also worked well. Sprayed it liberally into the connector several times to flush out the oil then let dry. Seems to be working great after the fix.

 PostPosted: Sat Mar 14, 2009 12:47 pm   
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Joined: Sun Mar 02, 2008 12:54 pm
Posts: 80
Location: "Live Free or Die"
Did this this today on my '02 LXI. Pretty easy job following the above instructions. (thanks!)

I suggest following Rmitch's advice to use a small screwdriver to remove the connector. I only spent a few minutes pinching and pulling before heading to the toolbox for a small flat blade. A few seconds later, and it was off.

My oil light was coming on solid at idle after warming up. Seems to be OK for now with the new switch. My old switch was not leaking, but I cleaned the electrical connector anyway.

 PostPosted: Sat Mar 14, 2009 1:35 pm   
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This kit will fix the flicker if your oil pressure is ok. You should check it with a mechanical guage before doing this. It is for the Intrepid but will work on the Sebring. I know there are some pictures out there on how to remove the sealing dart. Hope this helps....

NO: 08-36-99
SUBJECT: Engine Oil Pressure Light Flicker
DATE: Oct. 15, 1999
This bulletin involves adding a terminal/wire/vent to the oil pressure switch connector.


With a hot engine the oil pressure light may be on or flicker on at idle.

Verify engine oil pressure as described on page 9-21 of the 1999 Concorde/Intrepid/LHS/300M service manual (Publication No. 81-270-9140). If engine oil pressure is within specification perform the Repair Procedure.

Qty Part No. Description
1 05017800AA Wire Terminal/Vent

Raise vehicle on a suitable hoist.
Remove engine oil pressure switch connector from switch.
Remove sealing dart from the empty cavity at the rear of the connector.
Pull terminal locking ring outward from front (switch) side of connector to gain access to terminal locking tabs.
Install wire terminal/vent, p/n 05017800AA, in place of the removed sealing dart. Slide locking ring back into place.
Attach the connector back on the oil pressure switch.
Spot tape the wire/vent to follow the harness towards the top of the engine compartment

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