Perkins 4.236 Oil Leak

[Hermit]

Hello, looking for a bit of advice reference an oil leak I am suffering from at the moment.

Bought the boat April last year - engine is a Perkins 4.236. Original from 1977 but was taken out and fully rebuilt in 2001. Running really well and, apart from some issues with charging which have been sorted, never missed a beat all last season.

Came out over the winter and was serviced by a local company (oils filter, fuel filter and impeller etc). All seemed fine.

Put back in the water end of March and used a few times. Keep getting oil coming out of the sump discharge pump up on the side of the engine (quite high). Now this pump was not used to change the oil but was tried a few times to see if it worked.

Only seems to come out when pushing the engine a bit. I have 2 gauges which (allege) to show oil pressure - one shows 4 Bar/60psi the other shows about 10 bar. I have no idea which is ringtone as tracing the connections is a very difficult job. But, both gauges move when I start the engine - neither shifts from that position when running. The oil was right at the top and possibly slightly over the max on the dipstick but carried on pumping out of the sump drain until much lower than full.

Now, I can buy and fit a ball valve to stop the oil leaking out from the sump drain pump but I am worried about WHY the oil is there? I have seen threads on the Moody forums saying this could be a siezed ring and possibly terminal for the engine. I have got an engineer coming next week but want some sensible questions to ask them….

Also planning the Channels Islands this summer and staring to worry that is a bad idea!

Any thoughts?

Thanks

 

[Tim Good]

I’m sure this comment won’t be useful but I have the same engine and I do use the sump pump for oil changes. It’s pushed right down when not in use and presume there is some sort of rubber seal at the bottom of the pump rod which creates the suction to pump. If that had shredded then perhaps the oil pressure might force it up.

Mine has a little plastic pipe from the top of the pump but it’s bent over double when not used as it is possible that a small amount of oil can come up and out. The bent double pile basically creates a seal.

I doubt I’ve solved the problem and I should really know more about my engine but it’s always been reliable.

 

[Tremyporth]

I too have a 4.236 and two pressure gauges on the panel. One is engine oil pressure (60 psi sounds like that one). My other one is gearbox oil pressure. You might be able to confirm that without trying to trace the routes of the wiring by disconnecting the wires from one of the senders, then see if one of the gauges stops working.

 

[Tremyporth]

I was going to add, before I pressed the wrong button, that you might want to check whether the crankcase breather is clogged up.

 

[Hermit]

I too have a 4.236 and two pressure gauges on the panel. One is engine oil pressure (60 psi sounds like that one). My other one is gearbox oil pressure. You might be able to confirm that without trying to trace the routes of the wiring by disconnecting the wires from one of the senders, then see if one of the gauges stops working.

That makes a lot of sense, thank you.

 

[tillergirl]

I have a gearbox oil pressure gauge for my Perkins 6.354 with a Velvet Box. It runs at about 10 bar. Digging out the wiring diagram I see on the loom, blue/white is the sender from the Gearbox sender, brown/white on the engine oil pressure sender. Might be the same for you. Different engine of course but same family.

 

[Hermit]

So, an update…
Engineer on the boat Friday. Pump dribbling as soon as engine starts but thanks fully, no signs of excess crankcase pressure.

Take the sump pump off and nothing comes out the top of the tube which is about level with the injectors and nothing coming out.

Looking at the sump pump, there is a bearing in the booth which should be held down by a spring - this is loose and free to move. As you draw the pump, this is sucked up to allow oil into the body of the pump and then out. Working assumption is that, based on the vibration of the engine making the bearing move a bit like a jiggle siphon it basically sucks the oil out and past the washers in the pump and then the bilge.

Pump is now off and engine running fine. The next problem is what to replace it with. I have bought the Patay pump from ASAP but that is a 3/8 fitting. The pipe coming off the engine has a 1/2 fitting (olive and captive head) but the pipe OD is 16mm so I can’t find something with a 1/2 thread to fit over a 16, not standard 15mm pipe.

Any ideas where I might get something?