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Greetings all.. My Troll has only 10 PSI of oil pressure at idle when is up to running temperature.
When the engine is cold it can be as high as 80-90 PSI under light acceleration. 40 PSI seems to be the average reading I get under normal driving. Should I be concerned with any of these readings? PS. Oil change 100km ago.
 

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cold pressures seems ok hot pressures seem a bit low to me. have these readings shown only since last oil change? what oil was used? the more info the better chance of a meaningful response.
 

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Discussion Starter #4
cold pressures seems ok hot pressures seem a bit low to me. have these readings shown only since last oil change? what oil was used? the more info the better chance of a meaningful response.
Hey old ed, appreciate your reply. Workshop installed new drop on head with PENRITE 10W40. Have owned my Troll for the last 9 months. I brought her with promises from the previous owner of being fit for purpose towing a off road camper. Now have new head, new viscous hub and water pump, radiator, thermostat and rear main crankshaft seal. I suspect he sold the Patrol because he knew the head was cracked etc. The only pod gauge he had was a pillar mounted water temp gauge... Looks like he knew the engine had issues. I now have boost, egt and oil pressure gauges. It has always had low oil pressure at idle. (10PSI) when at operating temperature. 40PSI when driving in the city or on hwy. I installed these gauges about 8 months ago. Hope you have enough info, thanx again for your reply.
 

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Hot pressures are a little low but not enough to cause alarm. I would try 15w40 or even 20w50 as the weather heats up. See what the results of those changes are and monitor as you go. The fact that you see full pressure at startup seems to indicate there is no major problem, I think a viscosity change at the next service could help. Good luck.
 

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Discussion Starter #6
Hot pressures are a little low but not enough to cause alarm. I would try 15w40 or even 20w50 as the weather heats up. See what the results of those changes are and monitor as you go. The fact that you see full pressure at startup seems to indicate there is no major problem, I think a viscosity change at the next service could help. Good luck.
Thanks for your advice. Think the major problems I had are now resolved (touch wood) Will definitely try 15w40 as the weather gets warmer.
Cheers.
 

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Thanks for your advice. Think the major problems I had are now resolved (touch wood) Will definitely try 15w40 as the weather gets warmer.
Cheers.
My 2005 zd30 has been doing the same thing for ages.
It has done 230 000km and still seems ok,I did find an issue recently which has improved the oil pressure but still not what others seem to see.
roughly 15 psi at idle. I have a few posts about it. Does your oil light ever come on? Check your pressure relief valves, they could be sticking, mine didnt seem very free and the oil bypass valve was missing its internals,apparently the earlier DI's has a pressed cap on these that would come off and the ball and cap would end up in the sump.
I run 10w40 but will be changing to 20w50 , possible even 20w 60 as a trial.
Once I get a chance to test it under load properly I will have a better idea.
 

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Discussion Starter #8
My 2005 zd30 has been doing the same thing for ages.
It has done 230 000km and still seems ok,I did find an issue recently which has improved the oil pressure but still not what others seem to see.
roughly 15 psi at idle. I have a few posts about it. Does your oil light ever come on? Check your pressure relief valves, they could be sticking, mine didnt seem very free and the oil bypass valve was missing its internals,apparently the earlier DI's has a pressed cap on these that would come off and the ball and cap would end up in the sump.
I run 10w40 but will be changing to 20w50 , possible even 20w 60 as a trial.
Once I get a chance to test it under load properly I will have a better idea.
Hi, my 2004 has done 220 000km. Have owned this for 9 months, didn't know of this low oil pressure condition until I installed boost, EGT and oil pressure gauge. The low oil light has never come on either. This is my first diesel, its been a steep learning curve. I'll do some research on "pressure relief valves" Good starting point would be to know what they look like! :ROFLMAO:
 

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You can see the pressure relief valve on the oil filter housing. There is also a oil bypass valve.
The oil bypass valve is the one on top with the ball bearing-mine was missing.
My pressure relief valve did not move freely either.
But like I said previously this improved things but I am still not where others say their oil pressure is.
Today I changed to 20w50 oil to see if it had any effect.
At Idle when warm it sits at around 20psi and at 3000 rpm I am seeing 60psi.

I still need to get it out on the road for a long drive to see what happens as the oil gets hotter.
 

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Discussion Starter #11
You can see the pressure relief valve on the oil filter housing. There is also a oil bypass valve.
The oil bypass valve is the one on top with the ball bearing-mine was missing.
My pressure relief valve did not move freely either.
But like I said previously this improved things but I am still not where others say their oil pressure is.
Today I changed to 20w50 oil to see if it had any effect.
At Idle when warm it sits at around 20psi and at 3000 rpm I am seeing 60psi.

I still need to get it out on the road for a long drive to see what happens as the oil gets hotter.
Hi jono... Your a absolute legend! Thanks for the Nissan "Learning Academy Info" I have 10w40. I'm seeing 70-80psi at cold idle. Not sure of the actual rpm I'm quoting when I say 40psi at normal operating temperature. Will be interesting to check what PSI I'm seeing @ 3000rpm.
Interesting to see your change to 20w50 at idle is two times of what I'm seeing, I'm adamant I wouldn't see 60psi at 3000rpm. Workshop has changed oil and coolant upon fitting new complete head. I'll post findings of 3000rpm at operating temp. As the weather gets warmer I'll change filters and follow your lead and go with 20w50.
Appreciate your reply.
 

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Hi jono... Your a absolute legend! Thanks for the Nissan "Learning Academy Info" I have 10w40. I'm seeing 70-80psi at cold idle. Not sure of the actual rpm I'm quoting when I say 40psi at normal operating temperature. Will be interesting to check what PSI I'm seeing @ 3000rpm.
Interesting to see your change to 20w50 at idle is two times of what I'm seeing, I'm adamant I wouldn't see 60psi at 3000rpm. Workshop has changed oil and coolant upon fitting new complete head. I'll post findings of 3000rpm at operating temp. As the weather gets warmer I'll change filters and follow your lead and go with 20w50.
Appreciate your reply.
Hi , No problem, I am still figuring mine out too. Once I have tested it properly, I will have a better idea if the thicker oil is working. I am even willing to try 20w60.
In my opinion though, the oil pump needs to come out to be checked, but I am not that keen on doing it if I can help it at this stage.

I never used to see 60psi when warm, replacing the missing piece from the oil cooler housing has helped a lot.Try driving your car at more than 3600 rpm for more than 10 seconds, if you have a problem the oil light will come on. Mine was doing that whenever i went up a steep climb or went to overtake. This is what alerted me to the issue.
 

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Discussion Starter #13
Hi jono, My oil light is always on since changing the sender unit that came with the digital/analogue gauge however I am seeing 40psi @ 100km p/hr in overdrive. At 3300rpm 65psi. Sorry as this is not what you asked for. I'm happy for the temp light to be "on" now that I can see the exact oil pressure in real time. I think its a joke that the factory fitted temp gauge sits on 1/4 until the radiator boils, then it moves over to HOT. Bloody useless!
I'd be interested to hear of your findings in the future.
 

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So you removed the original sender? Did you not use a T-piece to mount the aftermarket sender?

I am happy to keep you updated. Once I get some time to test it properly, I will have a clearer picture. But I think ultimately I will be replacing the oil pump at some stage.
 

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Hi Jono,

I am Christian from Germany and I have a similar problem on my rebuild ZD30 DI engine, I start with the rebuild because of the low oil pressure and I change any bearing, piston and measure the oil pump, the pump was okay and was compare with the given data in the workshop manual. I found a leaked between the engine block and the steel plate behinde the timing gears.
But in the End the oil pressure isn´t at the given limits of the workshop manual.
So you wrote that you would change the pumpe, do you have any positive result after changing? because in Germany you can get the oil pump only togehter with the hole timing cover, because normaly the steel pumps destroy the cast aluminium alloy of the timing housing.
It will great if you or some one else have any solution in this topic, many thanks.
 

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To keep it very simple. If your oil pressure was low enough to be doing harm you would have a much louder engine. (Especially the top end) Any dramatic drop when driving and you would know All about it!! Drive on, she's fine😄
 

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Hi Jono,

I am Christian from Germany and I have a similar problem on my rebuild ZD30 DI engine, I start with the rebuild because of the low oil pressure and I change any bearing, piston and measure the oil pump, the pump was okay and was compare with the given data in the workshop manual. I found a leaked between the engine block and the steel plate behinde the timing gears.
But in the End the oil pressure isn´t at the given limits of the workshop manual.
So you wrote that you would change the pumpe, do you have any positive result after changing? because in Germany you can get the oil pump only togehter with the hole timing cover, because normaly the steel pumps destroy the cast aluminium alloy of the timing housing.
It will great if you or some one else have any solution in this topic, many thanks.

Hello Christian,
No I did not change the pump.
As long as your oil light is not coming on, I would not worry about it.
I am using thicker oil 15w 50 . This has helped raise the oilpressure slightly.
I have been running mine for over 100 000km since discovering the issue and no problems.
These engines have tough bottom ends.
 
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