Fuel getting into the oil

[Qapla]

We have a NH TC40D with a front loader and backhoe.

I seems like we may be getting diesel in the crankcase oil - not totally sure, but when we changed the oil today it had far more in there then it should have - and it smelled a bit like diesel. We have also noticed that the fuel does not see to be going as far as it should be - a sign of missing diesel.

Thing is, it seems to run just fine.

Any ideas?

 

[Dave M7040]

Usually it is the mechanical lift pump whose diaphragm is failing allowing diesel to enter the crankcase.
Dont know your specific tractor but on ebay these pumps are less than $50.
See my extensive post on same subject to a John Deere owner.
He later posted that indeed the pump was shot.
Dont ignore this as failed bearings or an engine seizure can result from being lubricated by diesel fuel!!!!
http://www.tractorbynet.com/forums/...3010-oil-dripping-everywhere.html#post4063338
Dave M7040

 

[Qapla]

Follow up ....

We replaced the mechanical lift pump.

Still have the problem. We are still getting fuel in the oil - not just a little, it is filling the oil pan with fuel.

Additional ideas ?????

 

[Harry in Ky]

Does it need to be running to transfer, or will it happen with the engine off? That type pump is not well known for leaking into the crankcase, but who knows?

 

[Leejohn]

fuel injecter pump is next.

 

[Dftodd]

Start checking fuel injectors. One is probably stuck open and over fueling

 

[FredH]

Fuel injector . Either Stuck , Cracked , or the seat is bad .

Been there , done that on a Detroit Diesel .

Fred H.

 

[Dave M7040]

Having been the one to suggest the lift pump, I am disappointed your problem continues.
If there is not excessive black smoke in the exhaust, it seems unlikely that a fuel injector is not sealing or over fueling.
I am with LeeJohn in now suspecting the injector pump. The main shaft for the injection pump enters a gear case at the front of the engine where all the timing functions take place.
If the seal for the injection pump shaft is gone it could be leaking fuel into the front gear case which is connected to the crankcase.
I am not familiar with your engine but in most cases the injection pump needs to be timed after removal to insure the fuel is injected at the correct place in the engine cycle.
Sometimes a special tool is needed to do the timing.
You could remove the pump and take it to a service facility which specializes in injectors and pumps. They can quickly tell you if there is a problem with the seal.
Re-installing the pump is the tricky part and you should either get a shop manual or find someone who knows how to do it so you don't cause any damage.
Having the injectors serviced at this time would be prudent. If you had the time I would even have the injectors serviced first and if there are no major problems then move on to the injection pump as doing the injectors is the easy part.
Plse keep the post updated as we will all learn from you on this.
Dave M7040

 

[Qapla]

From what we can determine, the fuel only gets in while the tractor is running ..... and, it takes a while. It doesn't happen all at once or as soon as we crank it up - but, if we work all day we will have about half an oil pan full of oil.

 

[Qapla]

Update

We changed the oil yesterday and what came out was full of fuel We put in fresh oil and ran the tractor for a short while. It ran fine and it was hard to tell if we were getting fuel in the oil but we think it was.

We shut it down before any damage could occur. Only thing is, we forgot to turn the fuel off.

Well, we checked it today and found the fuel gauge is down and the oil pan is completely full ...so, it appears that fuel IS getting in the oil when it is NOT running.

Any new ideas?