2001 Volvo Penta 4.3 - High Oil pressure

[ssquare14]

At idle the oil pressure gauge reads high and pegs full at WOT. I am running SAE 30. Can someone help with steps to diagnose high oil pressure?

My research tells me the first step is plugging in a mechanical gauge to get an accurate reading. From what I can see from parts diagrams their is a sender and a sensor - one located above the motor behind the distributer, and a second down near the dipstick/oil filter. Which one is which? Where do I tee in the oil gauge?

Important background that may influence troubleshooting - I purchased this boat used. Their was a riser gasket leak that caused milky oil. I repaired the issue and changed the oil (last season). I'm not sure if that would have messed with the oil pump itself or created some sort of blockage.


Thanks for any help

 

[ssquare14]

Edit: To add, I have a strong suspicion (b/c of a water line) the previous owner left the plug in at some point and the water was able to fill the bilge, possibly getting into the oil pan. The oil has been changed since then.

 

[Sunken Ship]

Mine is doing the same thing....80psi at idle/during crank then pegs needle at anything above idle. I think I will try a new sending unit at some point. The one on the back by the distributor is for the gauge. I would just pull that sender out and tag into the block with a cheap walmart gauge to make sure oil pressure is not that high then just put it back after checking. Note: there are others on here that know WAY MORE than I on this, but the one by the distributor is for the gauge.

 

[Bondo]

My research tells me the first step is plugging in a mechanical gauge to get an accurate reading. From what I can see from parts diagrams their is a sender and a sensor - one located above the motor behind the distributer, and a second down near the dipstick/oil filter. Which one is which? Where do I tee in the oil gauge?

Ayuh,.... Welcome Aboard,..... Both ports are pressure ports, so ya can T into either of 'em,.....

To see which thingy is a sender, or switch, pull the wire off it, 'n with the key"On", ground it against the block,....
If it's the sender, the gauge will peg to High,....
If it's a switch, the alarm will sound,....

 

[wkb2460]

This probably has nothing to do with the high pressure reading, but I believe Volvo Penta changed it's oil recommendation to 10w-40 full synthetic
a few years ago.

 

[ssquare14]

Bondo - I will ground the wire this afternoon and report back.

WKB - I didnt know they changed the oil recommendation. Is 10w-40 lighter weight?

 

[wkb2460]

I'm not an oil expert, so I do not know if it is lighter. My local Volvo dealer stopped stocking the Volvo Penta 30 weight Synthetic. He's the one who told me they switched. I have been using the 10w-40 Synthetic for a few years now without any issues.

 

[ssquare14]

Bondo- I removed the wires from both sensors. When I grounded the sensor on the block near the oil filter the alarm sounded. When I grounded the bell shaped sensor on the head near the distributor nothing happened (the gauge did not change). I replaced both sensors with parts from Napa (cross referenced to auto part not marine part). I ended up cutting, crimping, and soldering a new clip for the sensor near the oil filter because it was rusted out. Now when I turn on the motor, the alarm sounds immediately for about 5 seconds then turns off and the gauge still reads high oil pressure. I tee'd in a mechanical gauge on the sensor near the distributor and its reading 50psi at idle and doesn't change much at higher rpms.

Also, I know you're a wiring guru. I found what I believe to be a ground wire (black) on the back of the block that is not attached to anything. I am sure it is part of the problem, but when I tried grounding against various areas it did not do anything for the oil pressure problem.

 

[evantful]

Bondo - I will ground the wire this afternoon and report back.

WKB - I didnt know they changed the oil recommendation. Is 10w-40 lighter weight?

When Volvo discontinued their 30wt oil the recommendation for 2007 and older gas engines is Volvo's VDS-3 spec 15w40 (which is their diesel oil). 2008 and newer engines are to use Volvo's 10w40.

Any VDS-3 oil will work: i.e. Rotella Triple Protection 15w40, Delo LE400 15w40, etc

Continuing to use a high quality 30wt oil is perfectly fine also. If its conventional stick to 50hr OCI, if Synthetic 100hr OCI

There is a lot of miscommunication on this initially from Volvo Penta and was passed onto the dealers but later clarified this with a service bulletin.

 

[ssquare14]

To follow up on my thread for future readers, I replaced both sensors (about $25 each) and the oil filter, but pressure readings remained high. Then I bought a cheap mechanical oil pressure gauge from an auto parts store ($15) and tee'd it into the upper sensor. The oil reading came back around 50psi at idle and confirmed the oil pressure was indeed high. After speaking with a friend (car mechanic) and doing online research it seemed the next step was to remove the oil pan and check for clogs/pump. Unfortunately, this requires removing the motor in a boat (much easier in a car). I decided I was not up for this challenge and sold the boat on. When I bought the boat it had a significant case of milk shake oil, which I repaired by replacing the riser gaskets, so I'm sure the oil screen is just clogged with leftover gunk..

 

[Silvertip]

A clogged oil screen would cause low oil pressure -- not high oil pressure. A pressure relief valve in the oil pump is a more logical issue and if the engine sat for a period of time with water in the pan, rust could have made that valve inoperative.

 

[Scott Danforth]

Is this a new problem or a new to you boat? The reason I ask is I generally run a new mehling oil pump in every SBC, BBC or GM V6 I own if I ever pull the pan. I get 50 psi at idle, and 80 psi at 2000 rpm and above.

I run 15w40 rotella in most of my motors, except the new VW which is running 0w40 synthetic.

50 psi does not bother me for oil pressure at 700 rpm Low oil pressure does.

I agree that 50 psi is higher than normal idle pressure of 30 psi (10 psi per 1000 rpm is minimum pressure)