Qsd 2.0 oil pressure valve location

[Reflections]

We are currently trouble shooting our R-25 after dewinterization. We have low oil pressure although we had no issues when we winterized. Where is the oil pressure valve located? There was an earlier thread indicating this could be an issue but can not find where it is in the service documents. Can you help?

 

[captstu]

You may have a false low indication. There was a Yanmar 4BY2 service bulletin that address low and fluctuating oil pressure.


Stuart Bell
Ranger 25: Shearwater
(561) 352-1796

 

[NorthernFocus]

If you are asking about the bypass valve it is below the oil filter housing. How low is your pressure?

 

[Reflections]

We have basically no pressure, reading 1.7 psi.

 

[NorthernFocus]

We have basically no pressure, reading 1.7 psi.

If you just changed the oil, check to see if the oil filter housing has refilled. If not then the bypass valve is not a problem. Pump hasn't primed. You can prime the pump by pouring oil into the inlet port of the oil filter housing which is directly on the discharge of the pump. Then reinstall filter and try starting engine.

 

[NorthernFocus]

Or you have a bad sensor.

 

[AKDAVE]

I had the same problem on my QSD 2.0 last spring. My problem was solved as Dan suggested by adding oil to the filter housing. Figured this out after I put in a new oil pressure sensor.

 

[NorthernFocus]

I had the same problem on my QSD 2.0 last spring. My problem was solved as Dan suggested by adding oil to the filter housing. Figured this out after I put in a new oil pressure sensor.

To further explain this problem, the oil pump on the Cummins engine is a gear type pump and it is not submerged below the liquid level in the pan. After sitting idle for a long time (like all winter) the pump can get dry. Not sure how long it takes this to happen but it's quite a while. Months, not days or weeks.

When the pump is dry there is enough clearance in the gears in the pump that air can "slip" through enough that it can't pull adequate vacuum to pull cold oil out of the pan. When you pour oil into the center tube in the filter housing it pours right down into the gear pump. You aren't actually priming the pump in the strict sense of the word you're simply wetting the gears. The oil seals the gears enough to pump air until it pulls enough vacuum to draw oil out of the pan.

There are three things that help this. 1) fill the crank with warm oil that is easier for the pump to draw up the tube 2) overfill with oil so the pump doesn't have to draw as much vacuum 3) pour oil into the pump through the filter housing as previously described.

My boat sits for seven/eight months every winter and this is what I have to do during commissioning. The only time I didn't have to do this was the first year I owned the boat. Bought the boat in the fall and when I changed oil in the spring I followed the instructions in the maintenance manual and put six quarts of oil in it. Well the manual is wrong, the pan only holds four quarts. I guess the extra oil was enough to let it pull prime. The following year I put the correct amount of oil in and had the problem. I did the above to resolve it. Now I just do it as a matter of course. I guess the only way around it is to run the boat once in a while over the course of the winter. Or move someplace where you get to use the boat year around 😀

 

[Reflections]

Thank you for the help and information! Since we definitely don’t want to leave Alaska, it’s good to know how to deal with the issue! We put a heater in the engine compartment last night to warm everything up. Checked that there was oil in the drain port today after the temperaure outside came up above freezing. When we cranked her up today, our oil pressure is fine. I think maybe it has just been so cold it was more viscous than the system could handle. I’m blame no it on the April winter we are having.

Thank again for the help. So glad it’s almost boating season again! PWS here we come! 😀