MF 135 oil pressure

[ltolson]

My new to me 135 with a Perkins gas engine runs high oil pressure on the gauge. What worries me though is that oil drips out the dip stick tube after it warms up and at shutdown when I pull the dipstick there is a release of air pressure. I don't remember if it did this when I brought it home last month. I have changed the oil twice and both times the oil was black. The oil on the dipstick looks clean but I am concerned about the high pressure and leaking.
It had been sitting outside for about six months before I bought it. Could there be a blockage in the oil system or is it more likely the oil pressure relief valve in the oil pump?

 

[Tom from Buckeye Lake]

Sounds like the crankcase vent system is plugged up. I'm know nothing about Perkins, but there should be a tube from the valve cover or cankcase somewhere to vent the backpressure. Is there water droplets inside the oil fill cap? My 150 has a screw/expanding filler cap. Maybe yours has a vented filler cap, plugged up with junk?

 

[ltolson]

It has the same filler cap as yours and it does not have moisture on it. I will be looking at the valve cover vent tomorrow. I guess I didn't think that would increase the oil pressure. I hope you are correct. Thanks

 

[Dean]

The crankcase vent tube is at the front of the engine, running from the front of the rocker arm cover down to the bottom of the front axle support. They are prone to clogging.

A clogged vent tube could explain the apparent pressure in the crankcase but will have no effect on engine oil pressure.

Dean

 

[Fred T. Hart Jr.]

sounds like you may have two problems.

1. could be a faulty gauge, only way to check is hook up a remote gauge and see if both read the same oil pressure.

2. clogged motor block vent system, there is some blow by and it has to have a way to exit the system. In time guest the vent tube could become clogged, clean it out and be sure
do you feel some pressure coming out of vent tube when motor is running?

Good luck,

 

[ltolson]

I will be checking the vent tube as soon as it stops snowing. Getting another 6" here in SE Michigan.
The oil press gauge does not return all the way to zero after shutdown so I am hoping the tube is partially plugged causing the high readings.
The vent tube stops before the bottom of the engine. It seems it would be a better design to have it hang slightly bellow the front of the engine to allow more air to pass over it helping to keep it clear.

 

[ltolson]

Took the valve cover vent tube off and sure enough it was completely blocked. Decided to replace it with rubber hose and drop it slightly below the engine. If it blocks again I think I will just replace the whole hose. With all the bends in the original tube I don't know how it can stay clear for long.
By the way it did fix the leak problem from the dip stick tube. My oil pressure gauge will be replaced as well since it is the problem. I like easy fixes.
Thanks for the help.