Perkins Perama M35 Oil Leak

[Bill Robinson]

I have a Perkins Perama M35 with a big oil leak. This leak only occours when the engine is running, i.e. there is oil pressure and flow. About 1000hrs ago, there was a small leak from the rear crankshaft oil seal, so I suspected this seal, again. I replaced it, but the leak is still there. With the engine installed, I cannot see exactly where the oil is leaking, but it seems to emenate between the engine block, and the flywheel bell housing. With the engine out, and the bell housing removed, there is no way to fit the starter motor! Anyone with any ideas?

[Chief Engineer]

What are you trying to accomplish?

[Bill Robinson]

I am trying to find and fix this oil leak!

The only sure way would be to remove the engine from the boat, then set it up on a test bed , where it could be run and examined easily. Due to the restricted access, it is impossible to see where the oil is coming from when the engine is installed in the boat. Taking it out of the boat to a test bed is a major job, probably only possible during a haul out.
I was hoping someone else had perhaps had this problem, and knew of a solution that I could do with the engine in the boat!
I have the suspicion that the oil may be coming from a plug in the rear of the engine block, but to my knowledge these plugs are not usually covering oil ways.

[Bill Robinson]

The mysterious oil leak problem is solved! The cause was an oil filter that did not compress the rubber sealing ring. The rim of the filter was in contact with the side of the engine block, before the rubber sealing ring was compressed. Simple to fix, but I had to take the engine out twice to find this! The first time I removed the engine, removed the flywheel, and found there was a little oil there. I replaced the rear crankshaft oil seal, thinking that this was where the leak occurred. The second time I removed the flywheel, there was not a trace of oil, so I started looking elsewhere for the leak. I never suspected the oil filter, but decided to change it anyhow, as this is easy to do when the engine is out, and rather less so when the engine is installed, due to the limited access. That’s when I discovered that the spin on filters, the old and the new, touched the engine block. On both filters, the central thread was also not aligned to the outer casing, when you screwed them onto a bolt, this was obvious. The local auto spare parts shop said that this was a manufacturing fault with that particular batch of filters from Fleetguard. (I had bought two of them in Thailand prior to sailing to Chagos). On checking my service records, I found that I had used the same Fleetguard filters previously without any problems.

Unfortunately, we cruisers often have to buy whatever filters, vee belts etc are available, without the luxury of choice. I have learned another hard lesson, and will now check all spin on filters before installing them. Hope this helps someone out there, and thank you to all who replied to my post.

[GordMay]

Thanks for the update & information, Bill.

Sorry that you had to get into such a labourious can of worms, to solve such a minor problem. Glad to hear it was a minor problem.

[Wave]

Hello Bill

I see sometime ago you had a M35 engine, what are your thoughts now some years later on the engine. I am looking at Moody 35cc with one installed and your comments would be appreciated.