# Oil Sending Unit?



## AZdriver (Sep 8, 2005)

When I turn on the ignition only, without the engine running the oil pressure indicator points all the way up to high pressure. 

4.0 Liter V-6

Looks like the gauge is ok, but I suspect a bad sending unit. Does anyone know where it's located on the block & if it requires a proprietary socket to remove it?


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## jerryp58 (Jan 6, 2005)

AZdriver said:


> When I turn on the ignition only, without the engine running the oil pressure indicator points all the way up to high pressure.
> 
> 4.0 Liter V-6
> 
> Looks like the gauge is ok, but I suspect a bad sending unit. Does anyone know where it's located on the block & if it requires a proprietary socket to remove it?


I imagine your 4L is different than what my service manual shows for the '04 V6, but FWIW, that engine has the oil pressure sending unit down near the oil pump on the back side of the oil filter bracket (bottom front driver's side of the engine). I don't know if a special tool is required or not (hopefully, it's nothing more than a deep socket if you can't get an open end wrench or a crow's foot on it).

Are you still under warranty?


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## AZdriver (Sep 8, 2005)

*oil sending unit*



jerryp58 said:


> I imagine your 4L is different than what my service manual shows for the '04 V6, but FWIW, that engine has the oil pressure sending unit down near the oil pump on the back side of the oil filter bracket (bottom front driver's side of the engine). I don't know if a special tool is required or not (hopefully, it's nothing more than a deep socket if you can't get an open end wrench or a crow's foot on it).
> 
> Are you still under warranty?


Yep - still under warranty, but it's an enormous pain in the backside to have to drop it off for the dealer monkeys to spend ALL day with. For much less the cost of the rental car and possible special socket needed, I'll do it myself & take the defective part back to see if I can get credit on it.


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## avenger (Oct 7, 2005)

AZdriver you're now the 4th person, including myself, who has had this problem. I did it myself. The part is about $60, and I got a credit when I brought my old unit in. The sender is on the passenger side of the block, you'll see it hiding up there when you get under the truck.

No special tool was needed, just some patience as there is not a lot of room to work in there so you'll only be moving the wrench a little bit at a time.


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## aketler (Nov 10, 2005)

I am not quite sure if my problem is along the same lines as these. With the ignition on, engine off, my oil pressure reads right in the middle. When I start the engine in this cold weather, it pegs all the way at High, and any rpms above 2k will put it right back up to high. Seem like the same issue?


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## himilefrontier (Jan 21, 2003)

How cold? Oil pressure is normally high when the oil is cold since it has more viscosity then. One of my cars has a 20-30 PSI variance from cold to hot, so this may be normal.


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## aketler (Nov 10, 2005)

Below 40 - but the sensitivity to rpms remains long after the engine warms up. It usually take 10-15 minutes for it to calm down. That seem normal?



himilefrontier said:


> How cold? Oil pressure is normally high when the oil is cold since it has more viscosity then. One of my cars has a 20-30 PSI variance from cold to hot, so this may be normal.


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## himilefrontier (Jan 21, 2003)

It could be.....what is the actual oil pressure reading you are getting, or is it one of those vague factory gauges with only "L" or "H" to mark the readings? Also, what oil viscosity are you running? You are better off with a thinner oil in winter as it will flow more readily in cold weather. I live in Florida and have little experience with temperatures below 45 degrees and their affect on oil pressure , so most of my answers are based on conjecture rather that real practical experience with your actual situation. The AMC 360 V8 in my 1979 Spirit has 30 PSI at idle when cold and 5 PSI at idle when it runs hot FYI....


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## aketler (Nov 10, 2005)

5w30 mobil-1 full synthetic. As far as actual oil pressure, I couldn't tell you. Any other car I've owned had dummy oil gauges that didn't really move - this is the first one I've had where the guage shows pressure fluctuations. Kind of unnerving when it's pegged at the H. 






himilefrontier said:


> It could be.....what is the actual oil pressure reading you are getting, or is it one of those vague factory gauges with only "L" or "H" to mark the readings? Also, what oil viscosity are you running? You are better off with a thinner oil in winter as it will flow more readily in cold weather. I live in Florida and have little experience with temperatures below 45 degrees and their affect on oil pressure , so most of my answers are based on conjecture rather that real practical experience with your actual situation. The AMC 360 V8 in my 1979 Spirit has 30 PSI at idle when cold and 5 PSI at idle when it runs hot FYI....


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## himilefrontier (Jan 21, 2003)

I dunno then...you could try a cheap aftermarket gauge with a plastic tube that you could check under the hood.( $10 at the parts store if you can find one with the right threads) If the reading really is bad, the bypass spring is likely stuck or an oil passage is somehow obstructed. It could also be a shorted wire on the sender which is grounding and causing a false high reading.The factory gauge works on electrical resistance, and the sender either varies the ground to the gauge or if it is a 2 wire design, varies the positive side of the equation.


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## wcfields (Jan 17, 2007)

*Oil Sending Unit*

HI,
I am a new member. I also having oil gauge issues with my 06 frontier. One day while I was out and about the oil gauge stop reading the engine oil flow correctly. I was at a stop sign and the oil gauge show low engine oil flow. Then all of a sudden , the oil gauge needle swept to the high engie oil flow as if you were driven down the road.. Took it to a dealer and they have work on it several times. They could not fix the problem. I am trying to gather as much information as I can about oil gauge problems on the 06 frontier and 05 and 06 xterra. I am trying to build a case about the oil gauge malfunction to Nissan. It seems they are having alot of issues with their VQ4.0 and VQ3.5 engies. Would you please send any info any one has about their opil gauge not working right at: 


[email protected] and please title e mail oil gauge issue. 

Thank You wcfields


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## brewerro (Feb 5, 2015)

My 2006 Nissan Frontier 4.0 also had this oil gauge spike after a recent oil change, I was really concerned until I found on line this is most likely a sending unit sensor problem. I was told at the Auto Parts store that is was also most likely the sending unit as they had NEVER even sold a oil pump for this engine. I bought a new aftermarket 3 prong sending unit and once hooked up the oil level went directly to LOW and the RED oil light came on, I removed and put the old sensor back on so now I have no clue which is correct. The original sensor has beige color plastic and the aftermarket black - Any one have this type issue or answer to it?


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## smj999smj (Jan 1, 2006)

There have been a couple of people that have installed aftermarket oil pressure sensors on these engines and had the same thing happen. Either there's a bad run of sensors and/or the quality of them is really bad. Get a new, genuine Nissan sensor and it'll probably be fine.


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## BRubble (Jun 22, 2014)

brewerro said:


> My 2006 Nissan Frontier 4.0 also had this oil gauge spike after a recent oil change, I was really concerned until I found on line this is most likely a sending unit sensor problem. I was told at the Auto Parts store that is was also most likely the sending unit as they had NEVER even sold a oil pump for this engine. I bought a new aftermarket 3 prong sending unit and once hooked up the oil level went directly to LOW and the RED oil light came on, I removed and put the old sensor back on so now I have no clue which is correct. The original sensor has beige color plastic and the aftermarket black - Any one have this type issue or answer to it?


Since this occured after an oil change,, did you use a Nissan Oil Filter? If not,, then that's the first thing that I would do,, just to rule the filter out.

good luck


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## brewerro (Feb 5, 2015)

smj999smj said:


> There have been a couple of people that have installed aftermarket oil pressure sensors on these engines and had the same thing happen. Either there's a bad run of sensors and/or the quality of them is really bad. Get a new, genuine Nissan sensor and it'll probably be fine.



Well I purchased another new "aftermarket" sensor and thankfully this time the gauge worked correctly. I have become an expert at changing these out over the last few days. Anyone with this issue should do it vs. taking to a mechanic. Thanks again for the information..


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## BoulderTucker (Mar 3, 2015)

*Same issue?!*

I think I have the same issue as everyone here, but just want to be sure.

I recently bought a 2005 Frontier with the V6 and 95K miles. I live in Colorado and it has been cold recently. When I purchased it, I noticed that the oil pressure gauge moved within the normal range when driving. From what I read (I know very little about engines), this is normal. However, in the past couple of days, the gauge has been reading very high, sometimes pegged all the way on H. After driving for a bit, it goes down, but still stays in the higher range of normal. When the ignition is on without the engine running, the gauge is in the middle of the normal range.

I took it to my mechanic before I bought it (about a month ago) and they said that everything looked normal.

Thoughts? Am I experiencing the same issue as others in this thread? A bad sensor?

Thanks for any help!


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## smj999smj (Jan 1, 2006)

It sounds like a bad oil pressure switch. The 05 and 06 (and possibly the 07) models had a "real" oil pressure gauge system that used a 3-wire switch (actually a "sender") and when it failed, it would send the oil pressure gauge needle sky-high; normally, you won't see much movement of the needle at all. Later models had essentially a "dummy gauge." They used a regular oil pressure switch and the gauge is read in the middle or, if oil pressure dropped too much, showed no oil pressure. There have been a number of problems documented with those who have purchased aftermarket oil pressure switches, so I highly recommend you get the genuine Nissan part.


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## BoulderTucker (Mar 3, 2015)

smj999smj said:


> It sounds like a bad oil pressure switch. The 05 and 06 (and possibly the 07) models had a "real" oil pressure gauge system that used a 3-wire switch (actually a "sender") and when it failed, it would send the oil pressure gauge needle sky-high; normally, you won't see much movement of the needle at all. Later models had essentially a "dummy gauge." They used a regular oil pressure switch and the gauge is read in the middle or, if oil pressure dropped too much, showed no oil pressure. There have been a number of problems documented with those who have purchased aftermarket oil pressure switches, so I highly recommend you get the genuine Nissan part.


Thanks so much! So I assume that this is not a big problem and can continue to drive it until I replace the switch. As far as you know?


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## smj999smj (Jan 1, 2006)

A bad switch isn't going to hurt anything.


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## BRubble (Jun 22, 2014)

Also, make sure that your Oil Level is not overfull,, and you're useing the correct viscosity oil.

Good Luck


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