Diesel in the oil

[LEVIATHAN]

I am getting diesel in my oil on my Perkins 4154. I have fitted a new lift pump, changed the injection pump, and had the injectors checked. One of the injectors was piddling badly and was repaired, but I am still getting oil in the diesel. The engine starts easy with a small amount of light blue smoke. One the injectors was sooted up when I first removed them, then checked again after fitting the serviced ones and an injector was again sooted up.
About 1/2 litre of diesel per hour is getting into the oil which results in oil pressure dropping from 40psi until the alarm goes.
Can anyone help please.
Dave

 

[masterofnone]

Diesel in oil

If you supply the beer, I'll pop over and have it fixed in a jiffy.
Rich

 

[Billjratt]

Care to tell us all what you believe the problem is please?

 

[Ludd]

I am getting diesel in my oil on my Perkins 4154. I have fitted a new lift pump, changed the injection pump, and had the injectors checked. One of the injectors was piddling badly and was repaired, but I am still getting oil in the diesel. The engine starts easy with a small amount of light blue smoke. One the injectors was sooted up when I first removed them, then checked again after fitting the serviced ones and an injector was again sooted up.
About 1/2 litre of diesel per hour is getting into the oil which results in oil pressure dropping from 40psi until the alarm goes.
Can anyone help please.
Dave

First,welcome to the forum .Someone on here will have the answer,I,m sure!

Was the coked up injector on the same cylinder both times?Was a compression test done.?

 

[TQA]

I am getting diesel in my oil on my Perkins 4154. I have fitted a new lift pump, changed the injection pump, and had the injectors checked. One of the injectors was piddling badly and was repaired, but I am still getting oil in the diesel. The engine starts easy with a small amount of light blue smoke. One the injectors was sooted up when I first removed them, then checked again after fitting the serviced ones and an injector was again sooted up.
About 1/2 litre of diesel per hour is getting into the oil which results in oil pressure dropping from 40psi until the alarm goes.
Can anyone help please.
Dave

This is an odd one. Diesel in the oil on an old Perkins is almost always the result of a leaking lift pump diaphragm. However you fitted a new one.

A bad injector one that allows fuel to dribble into the cylinder usually produces lots of black smoke. Is it smoking? Is the engine producing full power?

Which injector pump do you have? Is the return from the pump clear?

Occam's razor says check that lift pump again.

I am interested because I too have a 154 in my old girl. Please post the eventual cure.

 

[masterofnone]

Return from lift pump

On my engine when the return was faulty,( fuel being supplied to the injectop pump, down the return) the idle was too fast and wouldn't stop on the stop lever.I know Dave has fitted a new lift pump amongst a lot of other things.
Oh yes, the reason I replied earlier, tis obvious. to bump it back to the top cos none of you replied. Come on Guys, help him out, then he'll stop ringing me!

 

[LEVIATHAN]

First,welcome to the forum .Someone on here will have the answer,I,m sure!

Was the coked up injector on the same cylinder both times?Was a compression test done.?

Thanks, It was the same cylinder, and no I havent done a compression test yet. I am going to check the tappets next.

 

[LEVIATHAN]

If you supply the beer, I'll pop over and have it fixed in a jiffy.
Rich

Thanks for getting the ball rolling, rich, about the beer, it will be cheaper getting a new engine

 

[LEVIATHAN]

This is an odd one. Diesel in the oil on an old Perkins is almost always the result of a leaking lift pump diaphragm. However you fitted a new one.

A bad injector one that allows fuel to dribble into the cylinder usually produces lots of black smoke. Is it smoking? Is the engine producing full power?

Which injector pump do you have? Is the return from the pump clear?

Occam's razor says check that lift pump again.

I am interested because I too have a 154 in my old girl. Please post the eventual cure.

Hi, I bypassed the new lift pump thinking it might be faulty. There is very little smoke definately not black. the injector pump is a lucas. I have checked the return which goes to the secondary filter via a none return valve, which is not there on a vehicle Perkins, it seems to have been fitted on marinisation. It seemed a bit dodgy so it drilled it out. still no Joy. I will double check the return from the filter to the tank.

 

[oldsaltoz]

Nothing to lose and simple, with engine idling, loosen the fuel feed line to each cylinder one at a time and re tighten.

The one that makes no change to the engine sound has the problem.

Could be hole in a piston or damaged rings allowing unburnt to bypass the piston to the sump.

 

[TQA]

Could be hole in a piston or damaged rings allowing unburnt to bypass the piston to the sump.

This usually produces clouds of dark blue oil smoke due to crankcase pressurisation and is easy to diagnose by removing the oil filler cap at tickover; the 'panting' is a clear indication of bad blowby.

On a 4 cyl diesel most people can hear if one cyl is out.

 

[pugwash60]

I had a lister once with similar symptoms and it was a broken ring, I don't think it was panting or producing blue smoke but it's so long ago I can't remember for sure, however I spent ages changing almost everything else as I thought that it was running ok when it wasn't.

 

[sailorman]

I had a lister once with similar symptoms and it was a broken ring, I don't think it was panting or producing blue smoke but it's so long ago I can't remember for sure, however I spent ages changing almost everything else as I thought that it was running ok when it wasn't.

some old listers had the fuel injector pump behind a plate, if a pipe or the pump leaked it would drain into the sump without being seen

 

[pugwash60]

That was my point, I thought it was to do with the pump behind the plate and changed all the pipes, pumps seals etc before pulling the pistons to find the real trouble.

 

[oldsaltoz]

.
I think I would be doing a compression test, starting with the cylinder that has the blacker injector. This will help eliminate piston or ring damage and indicate if valve clearance is ok.

First test compression note reading, then add a small amount of engine oil, enough to cover the piston head and check again. If compression improves it's most likely ring damage, if no improvement it may be a valve problem.

However for fuel to get into the sumo via the cylinder it must pass the piston via rings or a hole in the piston or very bad score/s in the bore.

With just one injector sooting up I would be investing this area first.

.

 

[jonathanhsm]

I had diesel in my oil on a Perkins Perama M20 - turned out it was a sticking exhaust valve and diesel was presumably pouring down open valve -
identifiable by engine "missing" - and white smoke

 

[masterofnone]

Possible answer

I had diesel in my oil on a Perkins Perama M20 - turned out it was a sticking exhaust valve and diesel was presumably pouring down open valve -
identifiable by engine "missing" - and white smoke

This I think could be plausible, to check would you take cover of and check tappet gaps, and/or a compression test?

 

[jonathanhsm]

sticky valve?

In my case it was obvious because rocker had broken - I guess ultimately you could do a compression test- but for a start you could take off cover -and turn engine over and see that the valves are all lifting- you could check the gaps but the essential thing is that the valves are opening and closing. if its stuck the stem will stay down when rocker lifts if you get my drift!
I ended up taking off the head and replacing the valves -and broken rocker - not that hard.
if it is a sticking valve its likely to be an exhaust valve - and its likely to be the one nearest the exhaust and seawater ingress!

 

[ean_p]

Hi Jonathan, excuse my ignorance but how does a sticking exhaust valve get diesel in quantity into the oil sump?

 

[david_bagshaw]

Hi Jonathan, excuse my ignorance but how does a sticking exhaust valve get diesel in quantity into the oil sump?

no compression, with a stuck open valve, or combustion with a closed one unburnt, some remains in cylinder, gets forced or goes down bores, past rings , into sump.