water in oil onan generator

[bluwateronly]

Hello all, I have a client that hooked up a freshwater hose into the raw water intake, so to flush out his system. The generator is a diesel onan model 5 mdkau. The motor would not start so here is what I tried. Jumped bat to house banks to make sure was not a low bat problem, turned over faster but still no start. Checked oil found milky looking oil, changed oil and filter, filter had lots of water in it. I have searched the web looking for an answer but could not find one. What is my next step, I am leary on using stater fluid or wd-40 the motor is getting fuel, checked at injectors. Do you think it will need to be rebuilt?

[hellosailor]

Water in the oil is usually a blown head gasket unless there's another way for the coolant and oil to mix, i.e. a passageway that has rotted out, a seal between the water pump and an oil passage, etc.

Someone who knows that particular genset might be able to shed some light on it, if not try Onan to see if it can be something besides a head gasket.

[bluwateronly]

I think the water got in by overcranking and using a water hose with pressure forced water into motor. Anything I should try that dosnt need a compression gauge, don't have one. Should I see if it will fire with starting fluid?

[kd3pc]

Originally Posted by bluwateronly

I think the water got in by overcranking and using a water hose with pressure forced water into motor. Anything I should try that dosnt need a compression gauge, don't have one. Should I see if it will fire with starting fluid?

until you know what the problem is and was caused by, the starting fluid is only going to cause parts puke...you still won't know what the problem is..

If you are sure the water got in by the hose or over cranking, and it has only been partially wet....change the oil and filter, spin the oil pump by hand and make sure you have pressure. If and only if, would I then try starting fluid...i.e. that would be the last resort.

It may be as simple as start being inhibited by interlock/solenoid or water in a needed sensor preventing it from answering properly....you will need a wiring diagram and multimeter to check this, or else a box of spare parts.

[dabnis]

Originally Posted by bluwateronly

I think the water got in by overcranking and using a water hose with pressure forced water into motor. Anything I should try that dosnt need a compression gauge, don't have one. Should I see if it will fire with starting fluid?

Very likely the cause, especially if it was running properly before the hose job. If it has a water cooled exhaust manifold water could have entered the exhaust ports. Water in or on the injector tips may be part of the problem? Perhaps removing the injectors, spinning the engine over to pass any remaining water out of the cylinder / pre-combustion chamber (if it has those)
may help. Change oil & filter, fuel filter, have the injectors checked by a shop and try to re-start it normally. Don't use ether if it has pre-chambers. If it has glow plugs glow the heck out of it. Let us know how it all comes out.

Dabnis

[bluwateronly]

Sounds like good advise. I don't use starting fluid as a rule I agree find the problem, thought I would ask anyway. I have changed the oil and filter and did not change the fuel filter however, I drained it from the valve on bottom and the diesel looked good. I will check the injectors and oil pressure and see if I see any rust or water damage.

[Rockter]

As long as you have not cranked the motor with the combustion chambers full of water, you should be pretty safe.

Drain the oil, change the filter.

Start it, run it, watch the oil colour carefully.

As the motor heats, the oil will slowly clear as the water fraction is boiled off.

If the oil colour shows signs of steadily worseing (it will turn a mustard colour), then you are still leaking water into the motor somehow.

[bluwateronly]

Just an update, the owner wanted to call cummings so when the tech came out he said the high pressure pump is getting fuel but not working. So the owner is deciding what to do. Just to let you know I am not a mechenic by trade I do other boat work mostly so losing this job was a blessing