I think my engine is making oil!

[lynall]

Story a couple weeks ago oil overfull warning came on, next day change oil stick in 7 litres level 1/4 inch below max mark, check a few times okay same level, then it started to get higher

Using no coolant, pas oil level correct, got to check atf but pretty certain no direct link to engine sump.

Oil looks and smells just like any other petrol engine oil.

Was thinking fuel in the oil but difficult to smell, also as injectors go into inlet manifold and engine runs and idles smooth does it usual mpg has made me doubt this route.

Last idea was the charcoal canister set up ie useing engine vacuum to pull fumes out of fuel tank so saving the enviroment, maybe this has gone wrong and is pulling fuel up? but again this is piped up to the inlet manifold.

Charcoal solenoid valve losated on the pass inner wing is quite often clicking all the time.

Any ideas especially ref the solenoid valve?

Got to go dinner is served:bannana:



Lynall

 

[lynall]

Lovely dinner spag bog

Going to suck out excess oil on saturday and check daily.

Maybe even unplug charcoal solenoid.



Lynall

 

[Dieselman]

I bet it's fuel dilution.

 

[kth286]

My thoughts also.

Needs a good long run.

 

[Will]

+1

Does the oil smell 'fuelly', and do you do mainly short journies in this car?

Will

 

[Smiley]

Had the same thing in an old jag - it was fuel getting into the oil after lots of short journeys - but you could actually smell the petrol in the oil on the dip stick.

 

[Howard]

Why do short journeys cause this ?

I typically drive 3 miles to work a day and then 3 miles back .... is this going to cause a problem ? I have the same engine.

 

[Will]

Why do short journeys cause this ?

I typically drive 3 miles to work a day and then 3 miles back .... is this going to cause a problem ? I have the same engine.

Hi Howard,

It's because when an engine is started from cold, it runs rich - in the same way as you would use a choke on an old car.

It takes a good few miles to warm the engine up properly - not just the coolant, but the oil as well (possibly more than 3 miles at this time of year).

The oil gradually becomes diluted over time by the slightly richer mixture and doesn't have a chance to get boiled off, so after a while the oil will start to smell of petrol/fuel and possibly the level can rise.

Short journies are also pretty bad for exhausts as they fill with vapour/condensation and never get hot enough to dry out etc.

Best solution would be to take it for a good run once in a while, and consider more regular oil changes (the ASSYST system helps here?)

Will

 

[Howard]

Ah , i do go and have a jolly once a week or so

Ummm , the ASSYST system , is that whats counting down to the next service ? because that is 5600 miles away ...

When i check the oil , it says OIL LEVEL OK .

 

[Dieselman]

Hi Howard,

The oil gradually becomes diluted over time by the slightly richer mixture

Just to expand on that, what happens is that the cold start mixture is so rich some of the petrol condenses on the cylinder walls and runs down past the piston rings into the oil.

 

[lynall]

Used 99% for work and its 12 miles either way so no short runs really, odd one into town a couple of miles and thats it really.

Wife has the v6 version and does lots of short runs and oil stays the same on that well so far!

Just recently (roughly 5 weeks ago) came back from netherlands and that was over 700 miles so that counts a a good run.

Oil smells like a petrol engines oil to me but as a spend all my life working on diesels, maybe i cant smell it, but it didnt stand out as petrolly.

Another fault occurred to me was a dribbly injector when the engine switched off, fuel running into bore past rings into sump, anyone know how long rail keeps its pressure with ign off?



Lynall

 

[Smiley]

Just to expand on that, what happens is that the cold start mixture is so rich some of the petrol condenses on the cylinder walls and runs down past the piston rings into the oil.

yep that was exactly what had happened to the jag - it was a great big V12 and it had been started and stopped without getting properly warmed up over a period of several months - replaced the oil and took it for a proper run - there was a huge smoke screen for about 5 miles whilst it cleared out - after that it was fine; apart from the fuel gauge that you could see moving - it did less than 10mpg sometimes.

 

[Smiley]

Another fault occurred to me was a dribbly injector when the engine switched off, fuel running into bore past rings into sump, anyone know how long rail keeps its pressure with ign off?



yes I wondered that as well - if it is that it wants sorting sooner rather than later as it will wash the oil off the bores.

I think you would smell fuel in the oil though with volumes big enough to show on the dipstick - the Jag oil stank. How about ATF I assume that would mix in a bit better? Coolant would not mix at all and you would see it in those quantities.

 

[lynall]

Thanks Smiley and everyone else for all the replies, will check atf at work tomorrow,drain oil and see how long before it comes back up again.



Lynall

 

[Dieselman]

Have you got access to a compression tester and leak down tester.?

If it was a dribbling inector at engine off it would lose pressure from the rail so be difficult to start when hot due to vapour locks.

 

[Will]

Another fault occurred to me was a dribbly injector when the engine switched off, fuel running into bore past rings into sump, anyone know how long rail keeps its pressure with ign off?



yes I wondered that as well - if it is that it wants sorting sooner rather than later as it will wash the oil off the bores.

I think you would smell fuel in the oil though with volumes big enough to show on the dipstick - the Jag oil stank. How about ATF I assume that would mix in a bit better? Coolant would not mix at all and you would see it in those quantities.

I have seen a CL55 (non-kompressor type) that was being repaired at an MB specialist after suffering engine damage supposedly from a leaking injector (hydraulic damage apparantly). Can't see how it would happen as when the engine is off and the fuel pumps aren't running, how much fuel would actually get through?

Anyone else come across leaking injectors on modern MBs?

Will

 

[spock500]

With diesels running svo short journeys can cause ring gumming leading to the same problem not sure if this applies otherwise though on std petrol cars?

 

[Dieselman]

Not exactly the same but I'm sure a good flush might help things..

 

[spock500]

Good tip by re: engine flush by HC,

http://www.vegetableoildiesel.co.uk/forum/viewthread.php?tid=3326&page=1#pid79823

 

[lynall]

Removed excess oil exactly 1 litre to get oil back down to max mark, have had a good sniff and not convinced its petrol have to get a second opinion

Dipped atf when hot just under max mark so okay.

Tested fuel rail preaaure when engine first off by pushing test point nipple with a screwdriver, then tried again an hour later and seemed the same to me.

I am going to see if i can get an adaptor for the test point so i can hook up a gauge.

Good point the poss starting fault as it hasnt got one! so assuming pressure holding okay, but would like to check with a gauge to be sure.


Lynall