Oil pressure relief valve

[Baydog]

I own a 2001 DF115, less than 400 hrs on motor. Last trip out the oil filter seal blew and puked oil all over the inside of the motor. At first I thought it was a bad oil filter seal, but on closer inspection there was visible swelling of the oil filter itself. I asked a local mechanic and he told me that I needed to replace my oil pressure relief valve (which involves powerhead removal) I removed the powerhead and noticed that the relief valve was partly unscrewed and resting on a crankcase ledge. The oil relief valve seems to operate fine if I push on it (like it's not stuck). Has anyone else ever run into a similar over pressure situation with their motors or have any ideas as to what may have caused this to happen. Could the valve being partly loose like it was have caused the problem. Thanks in advance for any insights.

[Cwkaun]

I'm sure someone here can answer that , good luck

[Baydog]

I'm sure someone here can answer that , good luck

Yes, I hope so. I haven't even heard of anyone ever having an issue with the high pressure relief valve on a Suzuki outboard. I'm hoping someone on this site has either had an issue or is aware of someone having an issue and can give me a lead or two as to what I should be looking at or for. The valve looks very solid and seems to operate easily, makes me nervous about it being the problem. I will replace it either way but would be a shame to put it all back together and just have it puke all the oil out again if the cause was something else. Seems really weird that it (the valve) was loose, almost falling out and I could remove it with just my fingers. But even loose, I think it still should have operated correctly, but I'm really not sure at all. Fingers crossed for some advice or experience from someone.

[Harper]

I've not heard of the issue, either. If anyone here has heard they will speak up. Be patient. Folks have a lot more on their plates than just reading this forum. I don't see any reference to your problem in a search, either. I'm not sure about the Suzuki outboard filters, but automotive filters have built-in pressure relief valves, meant to bypass a clogged filter. Might be a factor in your case, too. Did you at any time get a low oil pressure alarm?

Also, since I'm not familiar with the oil pressure relief valve, I'm unclear as to what you mean by "partly unscrewed, resting on a crankcase ledge." Does the crankcase ledge prevent the valve from being completely unscrewed? In other words, did the valve end up being more or less wedged between its seat and the ledge, especially in a fashion that would possibly hinder the proper operation of the valve?

I have a DF150, and I have no idea where to find the valve in my engine. The only mention of the valve in the service manual is in the oil flow chart, where it is shown right after the oil pump in the flow of pressurized oil. It is mentioned nowhere else in the powerhead section. I had assumed it might be in the oil pump housing, but it doesn't mention it in the oil pump teardown/inspection section, either.

[Baydog]

I've not heard of the issue, either. If anyone here has heard they will speak up. Be patient. Folks have a lot more on their plates than just reading this forum. I don't see any reference to your problem in a search, either. I'm not sure about the Suzuki outboard filters, but automotive filters have built-in pressure relief valves, meant to bypass a clogged filter. Might be a factor in your case, too. Did you at any time get a low oil pressure alarm?

Also, since I'm not familiar with the oil pressure relief valve, I'm unclear as to what you mean by "partly unscrewed, resting on a crankcase ledge." Does the crankcase ledge prevent the valve from being completely unscrewed? In other words, did the valve end up being more or less wedged between its seat and the ledge, especially in a fashion that would possibly hinder the proper operation of the valve?

I have a DF150, and I have no idea where to find the valve in my engine. The only mention of the valve in the service manual is in the oil flow chart, where it is shown right after the oil pump in the flow of pressurized oil. It is mentioned nowhere else in the powerhead section. I had assumed it might be in the oil pump housing, but it doesn't mention it in the oil pump teardown/inspection section, either.

Hi Mike. Yes I did get a low pressure warning as the pump quickly emptied my crankcase of oil. The powerhead must be lifted off in order to unscrew the high pressure relief valve, the ledge it hits on is part of the lower crankcase half and the valve screws into the powerhead itself, near the oil pump but not part of it and yes, it cannot be removed without removing the powerhead the ledge would prevent that as well, access to it near impossible with powerhead in place. You can see the high pressure valve with the valve cover removed though. The valve ejects excessive oil pressure through the sides of the valve, so I don't think sitting of the ledge would affect operation of the valve, but really weird that it was loose and unscrewed, torque recommended for it during installation is 19 ft. lbs. I think I will put a tiny bit of loctite on during reassembly just to be safe. I was using a Suzuki OEM oil filter and had 10w 40 oil dino oil in it. I will be using 5w-30 full synthetic from this point forward though. It was only a degree or two about freezing the morning this happened. Most likely theory to this point is that the valve momentarily stuck and with it being cold and the high viscosity oil inside the system rapidly over pressurized blowing the filter seal. This one is a head scratcher for sure. The high pressure relief valve can be found in the oil pump section of the parts cat. and lists for about $35.00

[Harper]

Well, you probably know about as much about the pressure relief valve on your DF115 as anybody. There's not one listed in the parts list for the DF150/175 at all. The manual does say that reasons for high oil pressure include stuck pressure relief valve, but I'll be darned if I can figure out where one is on the DF150.

Hopefully, the problem was a fleeting one, with a momentarily stuck valve as you suggested. So thanks, and keep us informed on the situation.

[mmanuel]

Not familiar with your motor but here's my SWAG. Hydraulic relief valves work on a simple principle, a spring loaded plunger or spool valve (two plungers connected with an open center) sits in a cylinder blocking the relief port in the cylinder and allowing pressure to build. As the pressure builds and pushes the plunger past the relief port, oil is released to limit the pressure. Hence, using a stronger spring or shimming it creates higher pressure.

If in your case, there is a spool valve in use and the open center is the relief portion opened to the relief port then possibly when the housing came loose it allowed the top part of the spool valve to cover the relief port completely, causing an unlimited pressure until it gained relieve by blowing the gasket. A swollen filter would indicate extremely high pressures!

I have not seen this in an oil pump before, but I've blown up a couple automatic transmissions due to this same issue. Hope this isn't confusing, check out the attached jpg. As in diagram B the bottom of the spool valve is allowed to go too high, then the relief port can be completely blocked!

Riddle me this, did the whole relief valve come out of the block, or just the top portion that keeps pressure on the spring?



Matt

[Baydog]

Not familiar with your motor but here's my SWAG. Hydraulic relief valves work on a simple principle, a spring loaded plunger or spool valve (two plungers connected with an open center) sits in a cylinder blocking the relief port in the cylinder and allowing pressure to build. As the pressure builds and pushes the plunger past the relief port, oil is released to limit the pressure. Hence, using a stronger spring or shimming it creates higher pressure.

If in your case, there is a spool valve in use and the open center is the relief portion opened to the relief port then possibly when the housing came loose it allowed the top part of the spool valve to cover the relief port completely, causing an unlimited pressure until it gained relieve by blowing the gasket. A swollen filter would indicate extremely high pressures!

I have not seen this in an oil pump before, but I've blown up a couple automatic transmissions due to this same issue. Hope this isn't confusing, check out the attached jpg. As in diagram B the bottom of the spool valve is allowed to go too high, then the relief port can be completely blocked!

Riddle me this, did the whole relief valve come out of the block, or just the top portion that keeps pressure on the spring?



Matt

Hi Matt, thanks for your response. The relief valve used in this application is a plunger style. The valve is a sealed unit and it doesn't appear that operation of the valve would be affected by it being loose. If the valve fell out completely you would likely have very little to no oil pressure. Quite the opposite of what I had happen. As I stated earlier, the valve expels excessive pressure out the sides of the valve in this case, not out the bottom, so sitting on the ledge as it was, it appears, shouldn't have impacted it's operation significantly if at all. The valve cannot come out completely because of a casting ledge directly below it. I believe the ledge is intentional to prevent a total lose of oil pressure that would occur if the valve actually did fall out.

[mmanuel]

A swing and a miss :0) That was the simple answer, if that's not the case then you have a major mystery to track down :0(

[Baydog]

Put the new valve in today and reassembled the motor. Supposed to be dropping below freezing here, pretty much until April now, so I'll have to wait until spring to test run. Everything looks good and not expecting any issues with the valve from this point forward. I put in 5w-30 full synthetic and that's all I will ever use in this motor from this point forward. I believe the 40 weight Dino is to heavy for late fall/early spring running. Replaced the water pump too. Figured I might just as well, seeing how it was down for repairs anyway. All set for spring now, just 6 months to go.