busterbrown1

This past Monday, I was driving back home during the torrential storms that rolled through the Detroit area. More than a dozen times I had drive through standing water about 12 inches high. When I arrived home and ad I parked my 98 Max in the driveway, I noticed the oil pressure indicator light illuminate on the cluster.

I'm only guessing that the oil pressure sending unit has failed during my puddle jumping adventure. Engine oil is full. Engine temp is normal. Car doesn't act any differently than normal. Is the sending unit on the oil pan? How easy is a swap out with a new one? Should i check actual oil pressures with a engine oil gauge test kit? Harbor freight sells one for $25 with multiple brass fittings? Do I remove the sending unit from the block and attach the gauge there?

Or should I just take the risk and replace the sending unit? O'Reilly's has it for about $13. Any help is appriaciated. Thanks

JvG

The first thing I would do is to check the oil dipstick. Does it seem at a nomal level? Does it look like oil, or like chocolate milkshake? If you have an A/T check that too. If the engine oil situation looks good, your probelm is elecrical. Your oil pressure sensor is most likely fine, your wiring not so much. Others may have had experience drowning their cars and resuing them. You might hear from them soon. Good luck.

busterbrown1

Thanks. Oil looks fine. It's at the same level from my previous interval oil change. About 5000 miles on Mobil1 full synthetic and looks appriopriate. car doesn't burn a drop of oil between changes. ATF looks red as I changed it about 10000 miles ago. This morning, I started the car and drove it about 6 miles before the light came on.

Wiring vs the sensor itself?? Maybe I'll just cough up the 13 bucks and replace the sensor. Just need to find it first. Unless anyone has other suggestions...

I did read someone where that the socket required to remove it from the block is an odd ball size. Something like 1 and 1/16 inch? Anyone know if this is true. I'll have the car up on ramps in the morning.

CS_AR

Hey Buster - Here's a picture of the oil pressure sender switch on the left side of the picture below. You can check to see that the plug socket is securely attached to the switch.



Here's another picture of the plug hanging loose (next to the CV boot) from another maintenance operation in the picture below.



If you decide to replace the switch, I have had good luck with the BWD Intermotor brand on multiple Nissan engines. I see Advance sells them for $11.59. If not OEM, then the only brand I will use is BWD Intermotor.

I use one of the following tools to remove the switch. I think you can use a long barrel socket also.

I'm usually short on long barrel sockets, so I usually pickup the tool.



As a side note, I also have the HF pressure testing kit. I've used it twice in the 4 years that I've owned it. I would first check for a loose plug before buying parts or tools. Note: our cars use British Standard Pipe Thread (BSPT) type sensors. If you decide to use a pressure testing kit, be sure the kit supports BSPT or the female threads could be damaged by using the incorrect thread type.

busterbrown1

Thanks for the advice, CS... In the morning, I'll attempt to remove the sensor. Is draining the engine oil required? (have a new filter and oil on hand if so) Also, what are the expected oil pressures at idle vs at specific RPM's? I purchased the HF gauge kit and will use it tomorrow when the OEM sensor is removed. Will look to see if the kit is BSPT compliant. I purchased a sensor removal socket from Oreilly's too. Hope it goes smooth tomorrow.

CS_AR

Not necessary to change the oil.. Though it never hurts.. Before I forget, I used a small amount of white Teflon tape on the threads roughly 1/4 inch in.. Let me see if I can find a picture. I found it in the slide show below. I got into the habit of using Teflon tape when I found it on the original Infiniti sensor. Check the FSM for oil pressures.

Here's a slide show from when I changed the sensor on my Infiniti's VH45DE in the link below.
It uses the same type of Nissan sensor as the Maxima though the V8 leaves lot less working room for changing the sensor as compared to the VQ30DE.

You can see how I used the coupling to test the BSPT sensor threads with the gauge threads. As I recall the gauge hose threads were the right size. I guess buying an Asian gauge worked out for the best as the kit had what I needed to run the test without. I don't remember much about running the test so I doubt that I had any problems.

http://s286.photobucket.com/user/Rid...1/Oil_Pressure


:

busterbrown1

Found the FSM oil pressure specs:

-@idle: more than 10 PSI (0.7 kg/cm2)
-@3000 RPM's: 63.1 - 79.9 PSI (4.44 - 5.62 kg/cm2)

busterbrown1

My numbers at full operating temp:

@ idle, 17 psi
@ 3000 RPM's, approx 76.

Right on target for the most part. HF gauge worked perfectly. Had to use the extension brass fitting and 90* elbow in the kit to be able to properly tighten the setup.

Nonetheless, I'll be out testing the new oil pressure sensor today. Did an oil change too as I already had the car on jack stands and the wheel off. Thanks for the help CS and JvG.

CS_AR

Thanks for letting us know the results.

Now doesn't it feel good to know you have plenty of oil pressure?

Happy Maximizing!

dwapenyi

iTrader: (3)

CS_AR

Give me a break DW.. I'm working inside a Ford truck door panel today.
It makes me crazy..

Fakie J Farkerton

iTrader: (51)

busterbrown1

Damn cool! I did have have a followup thought though. What's the failure rate on these 4th gen oil pumps? Better or worse than the timing chains? Approaching 115k miles (and 17 years) and would like to keep this vehicle road worthy for the nexr three to 4 years. Its my daily driver.

dwapenyi

iTrader: (3)

[QUOTE=busterbrown1;8977239].... What's the failure rate on these 4th gen oil pumps? [QUOTE]
Umm, like never. VQ engines just don't die, especially when you take care of them

my car is at 200k now. It'll make 400k easily. There are several examples of 300-400k plus Vq 30s in this forum

asand1

iTrader: (1)

At 300K I haven't had a problem. Never read about one either.

JvG

Your oil pump will be fine. I would be more concerned about electrical issues from the water you drove through and the corrosion it could cause.