Perkins 4108 Oil Pressure

[Russ Pichlik]

Working on a Perkins 4108 and oil pressure on gauge does not read but low pressure red light is out(comes on when engine stopped). Must be two senders??? One is on the mounting base for the oil filter, Where is the other one? Engine running fine for two and one-half hours from launch site to home marina so pressure is there! What to do???

[model 10]

Originally Posted by Russ Pichlik

Working on a Perkins 4108 and oil pressure on gauge does not read but low pressure red light is out(comes on when engine stopped). Must be two senders??? One is on the mounting base for the oil filter, Where is the other one? Engine running fine for two and one-half hours from launch site to home marina so pressure is there! What to do???

The other one is down on the left side near the starter and a bit fwd. There is an oil gallery along the block.

[John L. Cwierz]

I'm brousing this pressure thing on the M 4108 because after a 90 mile ride with my boat, which has a M 4108 Perkins, somehow water got to the semp. Now what's inside is plain mayonaise, jelatyn, or what have you. How on earth did water gotten into the oil semp?
Can anyone please advise as to where would I have to look? Maybe the washers and the retainers in the raw water pump failed to do their job and permitted water to mix with the oil? I already asked TED but no reply yet. Thank you.

[a64pilot]

Ref the water in oil.
First is it a fresh water cooled engine? If so check fresh water oil level first, if it's low then probably water in oil is coolant. Usually from a leaking head gasket.
But what you propose is possible and would be a much easier fix.
If it's a fresh water cooled engine the head gasket can be tested with a radiator pressure tester, it pressurizes the coolant and you look to see if the pressure bleeds off, cheap and easy to do.

Might want to start your own thread on this

[Bill Seal]

Simple and quicker to look for bad head gasket on fresh water cooled engine; disconnect circulating pump drive (remove belt), fill with coolant to top of filler cap neck, start engine, look for bubbles.

[model 10]

Originally Posted by John L. Cwierz

I'm brousing this pressure thing on the M 4108 because after a 90 mile ride with my boat, which has a M 4108 Perkins, somehow water got to the semp. Now what's inside is plain mayonaise, jelatyn, or what have you. How on earth did water gotten into the oil semp?
Can anyone please advise as to where would I have to look? Maybe the washers and the retainers in the raw water pump failed to do their job and permitted water to mix with the oil? I already asked TED but no reply yet. Thank you.

If it is the salt water pump it would take 2 seal failures to allow water into the engine. It seems like you would have noticed oil dripping from the pump if the oil seal had failed and like wise if the water seal had failed. I suppose both seals could fail at the same time and all at once but not likely.

[John L. Cwierz]

Thank you so much, you have been very helpful. John L. Cwierz