Low oil pressure in D6 engine

[atlantis43]

Hello
I am new to this and need a bit of help may be somebody already had an issue like this and can help me look in a right direction.
I have a Azimut Atlantis that is equipped with d6 400 diesels w 626hrs had it since 195Hrs.
About a week ago going through intracoastal by haul over inlet I ran the boat @3100 rpm max is 3500rpm and I pulled back the throttle leveler faster then usual and immediately got a low pressure alarm on starboard engine dropped below 10psi( normal at idle @600rpm both engines are @25PSI)
I turned of the engine looked in the engine bay to see if there are any visual leaks or signs of abnormality, I then tried to restart the engine and oil pressure was still low.
After I returned to the harbor I checked the oil level which was at the middle.
Since then I replaced the oil, filters all OEM not aftermarket along with the oil pressure sensor, also installed a manual gauge to verify that the oil pressure is low as per Volvo interface.
At the start up the oil pressure is the same on both engines and as soon as the temp of coolant goes up the pressure drops to 15psi and the other engine stays @25psi if I rev it up the oil pressure goes up.
I also tried switching an oil filter housing from one engine to another.
No weird sounds coming from the engine either please help or suggest what is the next step that I can take my self, talked to Jas Marine and they are saying they are 3-4 weeks out w their service appointments.
Thank you
Nick

 

[madabouttheboat]

Have you had the software updated? There is/was, if I recall correctly, a software mod to set the low oil pressure alarm to a lower level as it was going off when it didn't need to, particularly after a long hard run when the oil thinned out. As long as you have 1 bar, you are fine. Get it plugged in, or do a manual oil pressure check if concerned or the gauge is reading below 1 bar.

 

[atlantis43]

Have you had the software updated? There is/was, if I recall correctly, a software mod to set the low oil pressure alarm to a lower level as it was going off when it didn't need to, particularly after a long hard run when the oil thinned out. As long as you have 1 bar, you are fine. Get it plugged in, or do a manual oil pressure check if concerned or the gauge is reading below 1 bar.

As I said before there is too big of a difference between 2 engines one engine has 25psi another one is 15 psi at idle@600rpm @ working temp, and when I rev it up to 1,500 rpm it sometimes falls to 11-13 and then bounces back to 15, it is too big of a gap between the readings especially if it was @25 psi for about 430 hours? any other thoughts?

 

[Stemar]

Is there a pressure relief valve on that engine? If so, and nothing's rattling - big ends, etc, I'd suspect that. 600-odd hours shouldn't be enough to wear an oil pump, though that would have to be the next suspect.

 

[vyv_cox]

Failed pressure relief spring was my first thought although I am not sure this would satisfy all the symptoms. Perhaps the oil pickup fitting has loosened itself?

 

[madabouttheboat]

As I said before there is too big of a difference between 2 engines one engine has 25psi another one is 15 psi at idle@600rpm @ working temp, and when I rev it up to 1,500 rpm it sometimes falls to 11-13 and then bounces back to 15, it is too big of a gap between the readings especially if it was @25 psi for about 430 hours? any other thoughts?

Defo check the oil pressure with a manual gauge connected to the outlet in the oil filter housing. This will confirm if the low oil pressure is genuine, or if the problem is in the sender/wiring/gauge.

 

[ss2016]

I once had a similar problem on an aircraft so this might not be relevant. After a long hot flight pulled the throttle back and the oil pressure collapsed. It turned out to be a tiny bit of loose gasket material (must have been in there for years) was swept into the pressure relief valve so it did not fully close. I am not sure about a D6 but could there be a problem with such a valve?

 

[volvopaul]

Hello
I am new to this and need a bit of help may be somebody already had an issue like this and can help me look in a right direction.
I have a Azimut Atlantis that is equipped with d6 400 diesels w 626hrs had it since 195Hrs.
About a week ago going through intracoastal by haul over inlet I ran the boat @3100 rpm max is 3500rpm and I pulled back the throttle leveler faster then usual and immediately got a low pressure alarm on starboard engine dropped below 10psi( normal at idle @600rpm both engines are @25PSI)
I turned of the engine looked in the engine bay to see if there are any visual leaks or signs of abnormality, I then tried to restart the engine and oil pressure was still low.
After I returned to the harbor I checked the oil level which was at the middle.
Since then I replaced the oil, filters all OEM not aftermarket along with the oil pressure sensor, also installed a manual gauge to verify that the oil pressure is low as per Volvo interface.
At the start up the oil pressure is the same on both engines and as soon as the temp of coolant goes up the pressure drops to 15psi and the other engine stays @25psi if I rev it up the oil pressure goes up.
I also tried switching an oil filter housing from one engine to another.
No weird sounds coming from the engine either please help or suggest what is the next step that I can take my self, talked to Jas Marine and they are saying they are 3-4 weeks out w their service appointments.
Thank you
Nick

This is a common problem on this engine , it's not the fact that the pressure is low it's the fact that the sender and gauge stars can bus and the increments in range reading drop from say 15 to 10 psi not 15/14/13 etc so the sender sees 10 immediately from 15 placing the alarm on . I have had this with many engines more D6 than 4s , the oil cooler is the same size as the D4 , I personally think it's too small but that's Volvos design, therecweee some software upgrades but your relative new as it's the earlier A/B engines that were software updates to try and combat this along with the early pressure relief valve issues .

 

[volvopaul]

Hello
I am new to this and need a bit of help may be somebody already had an issue like this and can help me look in a right direction.
I have a Azimut Atlantis that is equipped with d6 400 diesels w 626hrs had it since 195Hrs.
About a week ago going through intracoastal by haul over inlet I ran the boat @3100 rpm max is 3500rpm and I pulled back the throttle leveler faster then usual and immediately got a low pressure alarm on starboard engine dropped below 10psi( normal at idle @600rpm both engines are @25PSI)
I turned of the engine looked in the engine bay to see if there are any visual leaks or signs of abnormality, I then tried to restart the engine and oil pressure was still low.
After I returned to the harbor I checked the oil level which was at the middle.
Since then I replaced the oil, filters all OEM not aftermarket along with the oil pressure sensor, also installed a manual gauge to verify that the oil pressure is low as per Volvo interface.
At the start up the oil pressure is the same on both engines and as soon as the temp of coolant goes up the pressure drops to 15psi and the other engine stays @25psi if I rev it up the oil pressure goes up.
I also tried switching an oil filter housing from one engine to another.
No weird sounds coming from the engine either please help or suggest what is the next step that I can take my self, talked to Jas Marine and they are saying they are 3-4 weeks out w their service appointments.
Thank you
Nick

You will get more feedback on the motor boat forum

 

[atlantis43]

I got it figured, thanks for all the comments, I did check the oil pressure with manual gauge, after all that I found that last thing that was not checked was a pressure relief valve that is located in the oil pump thus in the oil pan and the engine needs to be pulled, and will put a slight pause in a season, and that valve is responsible to drop the oil pressure when it is too high and it most likely got stuck open from last time. Before doing all that I decided to replicate the same conditions and took the boat out and ran in @80% load and then returned to idle slowly, and believe it or not oil pressure is the same now in both engines after all the stuff that i did that's all it took to remedy it will definitely never ever pull the throttle back like that. Fun fact is that that relief valve is under a $100 from JAss marine but the amount of labor to swap it will be astronomical since I would need to remove tender garage cover, tender floor, pull outdrive and then pull the engine to get to it. Hopefully the oil pressure will stay the same have a trip planned to bimini on the 5th of june.
Thanks again