TAMD41A - Diesel in oil

[bowler]

Hi all,

My port engine is showing signs of diesel in the oil. Both engines had an oil change earlier this year and there has been about 12 hours put on the boat since. The SB engine oil is certainly darker while the port engine oil is lighter and has a diesel smell to it. This engine also has a slight rock to it at low rpm. My plan was to pull the injectors and have them tested. Could the injectors be the cause of these symptoms? The oil is still around the max mark on the dipstick so not huge volumes of fuel I assume. I should add that the oil change was done by the previous owner so I am unsure of its condition.

If not the injectors then what else?

The only marine diesel mechanic I know can't get to the boat until late September so I guess future trips are cancelled for the time being.

Many thanks.

 

[colind3782]

Lift pump diaphragm perforated? Not familiar with that engine or if your one has a mechanical lift pump.

 

[kashurst]

if you are not getting blue smoke from the exhaust, oil pressure is OK, then I'm thinking fuel lift pump too. Almost certain it's not fuel injector related. Have a feel around the lift pump see if its got diesel on the outside. Might be worth cleaning it up then running the engine
relatively easy to change and @ £50 each.

 

[volvopaul]

Is the level going up on the dipstick? If not then it’s not leaking fuel into the sump .
If it is it could be the injection pump shaft seal too.

 

[bowler]

Thanks all for the replies.

It is a fraction high on the dip stick but not many hours on it since the last oil change. Oil pressure is 60 cold and around 30 warm.

I think I will change the oil and filter and replace the lift pump and monitor. Does that sound like a good start?

The injector testing will go ahead next month as planned. ASAP supplies sell the pump, as does Key Part but they say to buy two additional hose items if upgrading the new sealed kind (which I am). So in that case I should get all 3 items @ around £150 in total.

Sound good?

 

[volvopaul]

Rather than guess what’s in the sump carry out oil analysts check , plenty of kits on the market .

 

[jrudge]

When i had my injectors removed / refurbed / refitted I was told to check the oil level after half an hour running to make sure it was not rising with diesel.

So yes it can be injectors, but i suspect only if they have been messed with!

If the level has no risen to any degree are you sure it is diesel? I am not sure you would be able to smell a small ( not enough to really move the dip stick) volume of diesel in a very large volume of engine oil.

 

[oldgit]

Father had an on going problem with P6 after complete rebuild.which included injector check.
Fuel diluting lubricating oil.After run oil was further up dipstick and oil pressure drop.
Engine was removed dismantled and returned to the very respected engine company who did refurb..
Nothing obvious found .
Engine rebuilt and put back in boat.
Same problem.
Engine removed intact and sent for bench test
Turned out to be weeping injector.
Injector replaced and problem solved.

 

[Jim@sea]

If you urgently needed a Diesel Mechanic I would consider using a Mobile Mechanic such as the type that specialise in Agricultural Machines. If for instance your engine was a Perkins a Tractor Mechanic would be more familiar with this type of engine than a Boatyard that did engine servicing. Many Perkins engines are fitted in the Massey Ferguson Tractors
When I wanted my Thornycroft engine servicing I called in a local Agricultural Mechanic, he removed the Injectors and gave them to me to send (or take) to a Diesel Specialist) and when I got them back he re-fitted them.
all at £30 an hour with no Vat. And dont forget if you have it done to have a Compression Test.

 

[snowbird30ds]

Modern fuels tend to make older seals swell and go soft and often it's the seal in the injector pump that gives up and leaks straight into the engine without showing any external leaks, too much fuel in the oil can cause the engine to run away with no way of shutting it down and no rpm restriction, not easy to stall a boat engine! A co2 fire extinguisher to the air filter works well if it happens.

 

[bowler]

Hi all,

Thanks for the interesting replies.

Just thinking out loud. Could a leaking injector also cause my low rpm rocking? My plan is to get these out anyway and test them. I understand removing them is not entirely a straightforward process?