BMC 1.5 Oil level rise

[Big Bob W]

Around 18 months ago, I had an issue with the oil level rising quite rapidly in my BMC 1.5

It was obvious diesel was getting into the oil.
I replaced the lift pump and all seemed good for around 500 hrs.

I recently noticed the level had risen again on the dipstick. Not as dramatic as before. Around an inch on the dipstick. The engine has only ran a couple of hours or so over the last 3 months or so. 
Since noticing, I have ran the engine for 3 or 4 hours and the level has not changed a bit.

I’ve have today changed oil and filter and will continue to monitor closely.

Is it possible the injection pump seal had “dried” with lack of use allowing a diesel leak. Running the engine again for a while sealed it again?

Or am I about to have an expensive pump exchange??

 

 

 

[john.k]

If you read the material on this issue ,you will see that replacing the DPA shaft seals is not difficult,and should cost no more than a DPA seal kit.

[Tony Brooks]

9 hours ago, Big Bob W said:

Is it possible the injection pump seal had “dried” with lack of use allowing a diesel leak. Running the engine again for a while sealed it again?

 

Unlikely. I understand in days gone by the sulphur in the diesel caused the seals to swell as they wore. Now we have low sulphur fuel the sulphur in the rubber is returning to the fuel so the seal shrinks and leaks. It is a pump overhaul or a DIY seal fit. There are instructions somewhere on the forum.

[Tracy D'arth]

9 hours ago, Big Bob W said:

Around 18 months ago, I had an issue with the oil level rising quite rapidly in my BMC 1.5

It was obvious diesel was getting into the oil.
I replaced the lift pump and all seemed good for around 500 hrs.

I recently noticed the level had risen again on the dipstick. Not as dramatic as before. Around an inch on the dipstick. The engine has only ran a couple of hours or so over the last 3 months or so. 
Since noticing, I have ran the engine for 3 or 4 hours and the level has not changed a bit.

I’ve have today changed oil and filter and will continue to monitor closely.

Is it possible the injection pump seal had “dried” with lack of use allowing a diesel leak. Running the engine again for a while sealed it again?

Or am I about to have an expensive pump exchange??

 

 

 

I have never heard of the shaft seal becoming effective again after leaking. The attitude of the boat in the water will alter the perceived oil level because the dipstick is one the engine side not central. I would monitor it a while longer, sniff the oil on the stick, see if it is getting thinner. 

[Big Bob W]

Thanks all.

It’s ran another 5 hours or so and still no further rise in oil level. Very strange.

I don’t think it was the angle the boat was lying. The change of level seemed too much for that. I’ll keep a close eye on it, with fingers crossed!

[john.k]

Its typical of moderate diesel dilution for mixed /thin oil to burn more rapidly ,so in the first stages of seal leakage levels appear normal ,until the oil is so thin  pressure drops when hot.