Low Oil Pressure

The oil pressure in my TO-30 is around 20 psi which falls when it is warm, or the tractor is in a pull — why is this and what can I do about it? September 23, 2015.

That oil pressure is not ideal but tolerable, in fact my own TO-30 runs around the same. Assuming your engine is in relatively good condition, there are a few things you can check to possibly raise the pressure.

1. Ferguson originally specified straight weight oil for this tractor. Using 30 weight oil should maximize the oil pressure. You can run multi-grade oil but you will often find the oil pressure is lower when you do. The question then is, what weight oil are you using?

2. You can raise the oil pressure by increasing the pressure on the oil pressure relief-valve spring. Drop the oil pan and you will see the oil pump at the front of the engine. The relief-valve spring is in the round part of the oil pump casing than hangs down. Look closely and you will see a cotter pin in the round part that hangs down. The cotter pin holds the relief valve and spring in the casting. Remove the cotter pin and place several 1/4″ flat washers between the spring and the cotter pin. The washers will serve as shims and raise the pressure on the spring which will raise the oil pressure.

If however the oil pump is worn and or the crankshaft journals and bearings are worn the only solution is to rebuild the engine. That rebuild would include grinding the crankshaft and installing new bearings.