Not LS1 - But my daily now is showing 0 PSI Oil Pressure when warm
11-19-2013, 11:07 AM
#1
Not LS1 - But my daily now is showing 0 PSI Oil Pressure when warm Hey guys, I actually have a Nissan as my daily with the VQ35DE (same as the 350Z) and couple of days ago the oil pressure starting showing 0 PSI when warm on the gauge. Usually it shows about 14-15PSI hot and 45psi at 2k RPM when warm (which is what Nissan says it should run at). It shows about 30 now @ 2K.
I changed the oil and no difference in pressure. It's not making any weird noises. And I haven't beat on it.
Is a bearing shot? I plan to throw a mechanical gauge on it to see if the sensor is bad, but it seems to show an increase in oil pressure when cold or when RPMs are increased. And it shows a consistent 15psi drop across the RPM range. So, I doubt it's the gauge and more than likely a main bearing.
I went to German Castrol in it and the pressures went way up when cold but when warm looked normal. I had been running Mobil 1 in there and just went back. It's lowered down and have hit the bottom of pan multiple times, but nothing lately that would indicate an issue. And it's not leaking oil. I've thought about going to some Rotella 15W-40 to see if I can get the pressure back up.
Any thoughts?
I changed the oil and no difference in pressure. It's not making any weird noises. And I haven't beat on it.
Is a bearing shot? I plan to throw a mechanical gauge on it to see if the sensor is bad, but it seems to show an increase in oil pressure when cold or when RPMs are increased. And it shows a consistent 15psi drop across the RPM range. So, I doubt it's the gauge and more than likely a main bearing.
I went to German Castrol in it and the pressures went way up when cold but when warm looked normal. I had been running Mobil 1 in there and just went back. It's lowered down and have hit the bottom of pan multiple times, but nothing lately that would indicate an issue. And it's not leaking oil. I've thought about going to some Rotella 15W-40 to see if I can get the pressure back up.
Any thoughts?
11-19-2013, 12:37 PM
#2
I'd put a mech gauge on it and monitor it first. Similar issue happened with a Dodge truck of mine, but since I'm not sure if I'm understanding correctly what you're describing is happening, I'll refrain from saying it's just a bad sensor. Let us know what you find with the mech gauge.
-J
-J
11-19-2013, 12:47 PM
#3
I can't offer any help either, but subscribing for input. Worried that I might be chasing the wrong gremlin halfway into changing my oil pump due to lack of oil pressure at startup and ~15psi reduction in pressure at hot idle, but normal-ish pressure under load and at cold idle.
Does it sound different at all when the gauge reads 0? With mine, for the two times I actually started it to diagnose the problem, if I listened closely, the valvetrain was much louder until pressure kicked in, and then it quieted down. For that reason I skipped right over a sensor issue.
Does it sound different at all when the gauge reads 0? With mine, for the two times I actually started it to diagnose the problem, if I listened closely, the valvetrain was much louder until pressure kicked in, and then it quieted down. For that reason I skipped right over a sensor issue.
11-19-2013, 02:16 PM
#4
No, it still sounds good. It seems to run a little rougher, but I think the engine mount is worn. That's been an issue for a while. The oil that came out looked pretty good too.
And lastcall, what was unclear? I got it in the other day and the oil pressure was much lower. Nothing different had happened. I changed the oil and no change in pressure.
I have hit the oil pan a few times (as well as the frame) upfront because the car is very low, but nothing in the last few months. So if it was something there, it would have happened much sooner, I would think.
I just ordered a mechanical gauge. Should be here Wed or Thurs. I'll throw that on there and see what's happening. Hopefully, the sending unit for the stock gauge is going and is an easy fix. Car has 86k miles on it, so that wouldn't be unheard of for the sending unit to go out with that mileage.
Btw, the oil light hasn't come on and no other codes are being thrown. I think the nannies in that ECM are a little more robust than the stuff in the F-Body...
And lastcall, what was unclear? I got it in the other day and the oil pressure was much lower. Nothing different had happened. I changed the oil and no change in pressure.
I have hit the oil pan a few times (as well as the frame) upfront because the car is very low, but nothing in the last few months. So if it was something there, it would have happened much sooner, I would think.
I just ordered a mechanical gauge. Should be here Wed or Thurs. I'll throw that on there and see what's happening. Hopefully, the sending unit for the stock gauge is going and is an easy fix. Car has 86k miles on it, so that wouldn't be unheard of for the sending unit to go out with that mileage.
Btw, the oil light hasn't come on and no other codes are being thrown. I think the nannies in that ECM are a little more robust than the stuff in the F-Body...
11-19-2013, 02:19 PM
#5
I can't offer any help either, but subscribing for input. Worried that I might be chasing the wrong gremlin halfway into changing my oil pump due to lack of oil pressure at startup and ~15psi reduction in pressure at hot idle, but normal-ish pressure under load and at cold idle.
Does it sound different at all when the gauge reads 0? With mine, for the two times I actually started it to diagnose the problem, if I listened closely, the valvetrain was much louder until pressure kicked in, and then it quieted down. For that reason I skipped right over a sensor issue.
Does it sound different at all when the gauge reads 0? With mine, for the two times I actually started it to diagnose the problem, if I listened closely, the valvetrain was much louder until pressure kicked in, and then it quieted down. For that reason I skipped right over a sensor issue.
11-19-2013, 02:23 PM
#6
It wasn't unclear, I was just overthinking it, and that is not what I encountered on my truck. I would just put the mech gauge on when you get it and see what happens. This is doomsday scenario stuff I'm about to ask, but how hard did you hit the pan, and do you think it might have been hard enough to muck up a pickup or screen?
If you are impatient, I used a $.99 tire pressure gauge from autozone and a cheap oil pressure nylon tubing kit. Hooked right up in about 5 seconds and cost about $4. If you were bored and wanted to get it done before your gauge arrives...
-J
If you are impatient, I used a $.99 tire pressure gauge from autozone and a cheap oil pressure nylon tubing kit. Hooked right up in about 5 seconds and cost about $4. If you were bored and wanted to get it done before your gauge arrives...
-J
11-19-2013, 02:25 PM
#7
My last 12V dodge would do the same thing on the stock gauge, 0psi at hot idle but perfect in all other situations. So I put a mechanical gauge on to confirm it still had pressure, and luckily it did. The pickup is in the front of those insnt it? Maybe at idle it just can not create enough suction if its been caved in to much?
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11-19-2013, 03:59 PM
#8
I believe it's in front. I just don't have anywhere to get it up and check it out. The Trans Am has all of that at the moment...
I might just use my crane and pick it up and pull the pan. I had the oil changed at the tire place around the corner from me and it looked okay when I was under it. But I'll see if I can't pull it.
My wife will be really happy. Two disassembled cars blocking the garage and driveway!
I've been thinking of getting rid of the Nissan and getting an old beater truck. It must not be happy with me...
I might just use my crane and pick it up and pull the pan. I had the oil changed at the tire place around the corner from me and it looked okay when I was under it. But I'll see if I can't pull it.
My wife will be really happy. Two disassembled cars blocking the garage and driveway!
I've been thinking of getting rid of the Nissan and getting an old beater truck. It must not be happy with me...
11-19-2013, 11:43 PM
#12
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The one time I had this happen (non-LS), I replaced the oil pump and pressure pegged like 75 on cold start up. That's all it was, a super weak pressure relief spring fatigued from age.
01-31-2014, 06:04 PM
#13
Just thought I'd bring this back in case anyone has a VQ35 equipped vehicle in their garage (that spans everything Nissan makes except the 350Z and Titan).
There is a cover... Nissan calls it rear cover even though it's on the front of the engine... but it's behind the timing chain... has two paper gaskets in it. They are known for blowing out between 75k-90k miles in most motors. It's a $110 part to replace the entire cover, but it requires basically disassembling the whole car to get to it. 14 hours quote from the dealership.
As long as I have thicker oil in or am above idle, I have oil pressure. At idle, it leaks out slowly and burns up, starving the topend. I developed a tick in the cold from this.
So, as soon as my T/A is back up and running, pulling the Nissan apart (maybe throw some cams in there too) to fix up a stupid design flaw.
Fun.
There is a cover... Nissan calls it rear cover even though it's on the front of the engine... but it's behind the timing chain... has two paper gaskets in it. They are known for blowing out between 75k-90k miles in most motors. It's a $110 part to replace the entire cover, but it requires basically disassembling the whole car to get to it. 14 hours quote from the dealership.
As long as I have thicker oil in or am above idle, I have oil pressure. At idle, it leaks out slowly and burns up, starving the topend. I developed a tick in the cold from this.
So, as soon as my T/A is back up and running, pulling the Nissan apart (maybe throw some cams in there too) to fix up a stupid design flaw.
Fun.
