Cat 311 Oil Level Up

Mike007 · Sep 6, 2020

I have a Cat 311. Running machine the other day and oil pressure alarm went off. Checked oil level and it looked above full. Drained, changed oil, new filter. Ran machine 2-3 hours and alarm again, oil level is up. Haven’t had oil analyzed but thinking fuel in oil. What could be the cause? Thanks

Tyler d4c · Sep 6, 2020

Fuel pump leaking fuel in to engine more then likely

sergioasmi · Sep 8, 2020

remove the cover on the valves and see the inyectors have a fuel leakes is a commun problem

Mike007 · Sep 8, 2020

I spoke with Cat service and they stated the only 2 places fuel could enter are the transfer pump (easier fix) or fuel injection pump (harder).

Not sure why they didn't indicate injectors as a possibility.

Tyler d4c · Sep 8, 2020

Mike007 said:
I spoke with Cat service and they stated the only 2 places fuel could enter are the transfer pump (easier fix) or fuel injection pump (harder).

Not sure why they didn't indicate injectors as a possibility.

They are not as they are outside the valve cover. Some engines it is a possibility tho

sergioasmi · Sep 9, 2020

please the seria number

Mike007 · Sep 9, 2020

5PK01111

6LK04180

sergioasmi · Sep 10, 2020

if you have this type of injector this is the problem remove the cover an you'll see the leak on the injector

Tyler d4c · Sep 10, 2020

sergioasmi said:
if you have this type of injector this is the problem remove the cover an you'll see the leak on the injector

View attachment 224093

I was thinking 311 no letter with a 3064 engine I stand corrected

Mike007 · Sep 11, 2020

You say "you'll see the leak on the injector" - how do you mean, what should I be looking for?

Nige · Sep 11, 2020

Mike007 said:
You say "you'll see the leak on the injector" - how do you mean, what should I be looking for?

Remove the valve mechanism cover. Run the engine at low idle for a few sconds only. Be very careful of high pressure fuel spraying but look for fuel pi$$ing out from anywhere around the injectors or their fuel line connections. If the oil level is going up noticeably in 2-3 hours the leak shouldn't be too hard to spot.

Mike007 · Sep 12, 2020

Here’s a pic with valve cover off. Does it look as you thought? Injectors where they are doesn’t seem as though I’d be able to see a leak. Haven’t run it yet.

Tyler d4c · Sep 12, 2020

Mike007 said:
Here’s a pic with valve cover off. Does it look as you thought? Injectors where they are doesn’t seem as though I’d be able to see a leak. Haven’t run it yet.

That is a 3064 the injectors are not under the valve cover just as I thought your problem is the transfer pump or the injection pump

Mike007 · Sep 12, 2020

Thanks, what is it with the transfer pump that causes the leak? I ordered a new O-ring and going to pull it off but not sure what to look for.

Nige · Sep 12, 2020

Apologies. I thought what sergioasmi posted above was what you have, obviously from the photo it's not.

Mike007 said:
Thanks, what is it with the transfer pump that causes the leak? I ordered a new O-ring and going to pull it off but not sure what to look for.

There is a pin (circled) that is not identified on the drawing below. That pin fits between the tappet and the piston. Wear in the pump body where the pin passes through it is the likely spot for a leak. There is no bush or seal at that point.

Mike007 · Sep 12, 2020

Thanks Nige. I’m struggling to see how the transfer pump leaking results in fuel in the case as it is bolted to injection pump. Regardless, if it is wear and leaking should I just replace it? Not sure if there is any way to confirm it is at fault once off.

Also if it is not the transfer pump, what would the fault be with the injection pump?

Thanks

Tyler d4c · Sep 12, 2020

Mike007 said:
Thanks Nige. I’m struggling to see how the transfer pump leaking results in fuel in the case as it is bolted to injection pump. Regardless, if it is wear and leaking should I just replace it? Not sure if there is any way to confirm it is at fault once off.

Also if it is not the transfer pump, what would the fault be with the injection pump?

Thanks

Don't hold me to it but the lower workings of the injection pump are lubed using engine oil so thats how it can cross over atleast im 99 percent sure thats the case.

Nige · Sep 13, 2020

I am of the same opinion. Really need thepumpguy to chime in. He would know for certain.

thepumpguysc · Sep 13, 2020

I need to see exactly what the inj pump AND supply pump looks like to make an informed decision..

Mike007 · Sep 13, 2020

Thanks very much, hopefully one of these pics will work.

Cat 311 Oil Level Up

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