Water getting in the oil supply

Most likely reason is blown head gasket, look at oil filler cap if it has oil and water mixed into white gloopy stuff it's pretty certain. You will need to replace head gasket to fix it.

Engine tank should be plumb full tight. The engine supplies about 2 lbs pressure through one of the 2 lines going to the boat tank. The other line takes the oil to the engine tank. If that line gets kinked or pinched, the engine tank won't get oil, a check valve lets a little air into it, and the oil pump keeps getting oil. When it goes down just a little, the alarm goes off telling you something is wrong.

Sludge in the boat tank could plug up the pickup screen. I've also seen them plugged up by a foil oil bottle seal carelessly dropped into the tank.

Once you find out why the oil couldn't get there, start the engine with the cowl off and loosen the cap on the engine oil tank until it leaks, then tighten it down and clean up the mess. That tank is normally plumb full tight.

If when the engine is running, you crack the cap on the boat tank, you should hear pressure let off. If the cap leaks, it won't build up pressure. If there is pressure, the oil line is plugged or kinked.

If pressure isn't supplied, the problem would be the crankcase check valve on the engine, lower forward starboard side, with the hose going to it.

hope it helps

if it is an automatic transmission the problem will be a split cooling tank that is inside one of the radiator tanks
the fix is a new radiator and a full flush of the cooling system

The "9141" is an ISO standard (general) alert... Not a code.

Some better engines DO NOT handle water in the fuel well... and Honda is definitely a BETTER ENGINE (Highly recommend fuel treatment here)..

Sorry to hear about your troubles.
SADLY... "too much oil" opens a whole world of possibilities.

None of them being good... It is way worse than running with "not enough oil"... Oil, water or any liquid DOES NOT COMPRESS and in an enclosed explosive environment can perfectly transmit (hydraulic: fluid dynamics) all that power to the WEAKEST SPOT in your engine... Hopefully a oil filler cap or tube seal... rather than a head-gasket .

Typically blue smoke is oil... brown/black is gas (black = drowning) and WHITE is water... Hopefully your fuel supply got a dose of water into your gas tank. Any alcohol based additive can cause minimal water in the fuel tank to be harmlessly absorbed... and allow it to be consumed.

A compression test will give a good idea of the current condition of the heads, cylinders and pistons.

Water is a NATURAL byproduct of combustion... so a little moisture should not alarm... but continued white smoke from a warm engine should provoke great caution. Sudden drops in coolant levels... means plan on some serious mechanical work... White or grey froth in the OIL... means you should cease engine operation immediately (the motor MAY still be salvageable).

Check that oil first...

Hoping it is a trivial trouble...!!

That would depend on where the water is ... in with the oil or in the gas tank, etc. If in the gas tank, use 'dry gas' which can be found at any auto supply store and most hardware stores. Follow directions on the bottle and that should do it. If the water is in the oil, the best thing to do is take it in for an oil change and mention that you think there might be water in the oil, although the oil "should" get hot enough when your engine reaches it's normal operating temperature to vaporize the water and the water should vent.

you need to take this to a shop. a flashing check engine light means that what set the light is causing harm either to the engine or the emission system. the lose of oil could be the truck burning oil if you have checked for oil leaks and have not found any.

Oil is entering water system via a small leak in the head gasket adjacent to the oil drilling where the oil comes from the pump through the head gasket up to the head itself to lubricate the camshaft / valve gear. Or, there is a problem with the oil cooler found on a lot of Renaults. If you look at the oil filter there may be a metal donut looking piece with 2 x 3/4 water hoses attached to it. Because the oil pressure is 40+ lbs and the water is 14lbs when running, and if the cooler has an internal leak / fracture, the oil will gradually pass to the water jacket by virtue of the greater pressure.
Disconnect the 2 hoses and join the 2 block ends together with a length of hose, refill the coolant, run the engine for a while and see if there is any trace of oil or bubbles coming from the now open oil cooler stubs. If there is then the cooler is leaking internally. Replacement is the only option. The biggest problem you face is that the engine block, radiator, heater matrix are all carrying the oil sludge that's been circulating the water system. Cleaning all that out successfully may be your biggest quest.
How do I know all this, I'm just doing the same job on a Renault Clio diesel!!
Get some quality help, prepare yourself for changing the head gasket, timing belt etc. I'm going to flush mine with a strong detergent mix on reassembly, running a garden hose into the upper rad stub and allowing the lower to vent out and hope it brings most with it. Only a hot washer would help and I've bought a new header tank from online to replace the discoloured one when there's no gunk left. Good luck.

Replace radiator water by adding coolant

If it is allot of water you will need to pull the tank, if the water is muddy you will need to pull the tank. If it is just a little water you can pump it out by using the in tank electric fuel pump by jumping the fuel pump relay and powering up the pump all the time. If the water has been in the tank very long you may have much more serious problems with parts like injectors being ruined from water deposits and rust. In some cases you can absorb the water by adding a pint of denatured alcohol to the tank, it is available from any hardware store.

you checked your water in the reserve tank and there is water in it? well awesome man good to know!! ha ha there is water in mine too,

no but seriously i think you mean oil right?
if you have oil in your antifreeze reserve tank it usually means you have a blown head gasket, and that you will need to replace,
take it to a mechanics shop you trust as it will be not a cheap fix because they will need to take off the head to get to it.