Volvo Penta 2003 loss of coolant

[cam11585]

I went to start my VP 2003 for the first time in a few months a couple days ago and ran into some problems. Here is the symptoms as I saw them. The onset of these symptoms was very sudden.

The engine did start successfully and seemed to be running smoothly. After a few minutes I noticed the flow of raw water out of the exhaust was not as robust as it usually is. This led me to open up the engine compartment where I noticed a complete lack of coolant in the reservoir. I then checked the oil and found it thoroughly infused with water, just a milky mess. There was no evidence of coolant in the bilge so I'm assuming the coolant somehow found its way into the oil.

I then proceeded to start tearing things apart to try to locate the problem. The first thing I removed was the exhaust elbow because about 4 years ago I had the raw water outlet in this get clogged and cause raw water to back up into the engine. I replaced the elbow, and also rebuilt the raw water pump, and have had no issues since. The elbow looks relatively clean now, confirmed by running water through it with a hose. I then opened up both the raw water pump and the heat exchanger. Both look fine.

I'm at a loss of where to go from here. Any ideas? To be frank, I'm pushing up against the boundary of my comfort zone as a diesel mechanic and wondering how much work is worth it on this 35 year old engine with 3000 hours.

[joaoporto]

Did you try to check the heat exchanger?

[spotfire]

I've had the 2000 series for over 15 years.

I think your raw water pump rear shaft seals are going out. The raw water pump shaft runs off the timing gear. The rebuild kit is less expensive than a new pump. and comes with a new shaft.

The coolant cycle never interacts with the oil. I don't disregard the coolant escaping in the exchanger, easiest way to check is to plug the front end of the coolant line run air in the coolant tube, watch for air bubbles coming out the other end, or the freshwater output.

Good luck

[cam11585]

I rebuilt the raw water pump about 4 years ago so I'm somewhat dubious of that being the issue.

It's still a mystery to me where the coolant went. Can you elaborate on how to check the heat exchanger? I took it out and it looks fine but there's a lot you can't see.

[baltic sailor]

The raw water enters at the pump. In all other places the oil pressure is higher than the water pressure. Somebody messed up the seal rings in the pump. Normally in this case water comes out of the small hole in the pump but if the seal is in the wrong place....have seen it....not a theoretical issue. It's easy done during repair of raw water pump.

[spotfire]

Your coolant runs from the centrifugal pump through the heat exchanger tubes. The gear driven impeller pumps cool seawater around the heat exchanger tubes then out the exhaust.

If the tubes have a pinhole, you should be able to check the leak by testing the tubes with compressed air. Check out the coolant system schematics on the internet and you will get the idea.

[jkishel]

You say the coolant reservoir is very low and the oil is milky. Sounds like the coolant found it’s way to the oil pan. This can happen because of a blown head gasket, a cracked block or a leaking oil cooler (if you have one).

[Tcubed66]

It would be impossible for either pump to allow water into your engine from a faulty seal. Raw water pump is separated between the two by free air and coolant pump is not on any oil side. Heat exchanger doesn’t allow it either. Now if it a turbo then possible from the oil cooler.

[Kerry1]

If all other suggestions don't seem to provide the correct answer, suspect either a blown head gasket where the water jacket has leaked through to the cylinder/s and thus coolant into the oil, or corrosion/crack where the water jacket in either the cylinder head or the engine block have allowed the oil/coolant to intermingle. In the case of the cylinder head gasket, most likely you will see there is more pressure on the coolant side than there should be. In a conventional engine one would take the radiator cap off and see bubbles issuing strongly from the surface of the coolant. Hope that it's just the head gasket rather than corrosion through the castings which is much more expensive.

[moseriw]

cam11585 I think you are one wrong path! You mentioned milky oil. Though the water did vanish into your engine oil. You are a diesel mechanic... I bet it is the head!

And an old engine is the best you can have. Even old Volvo's. Do not buy a new Volvo, the quality is faaar less then the old ones.

I have a 1881 Ford Lehman with unknown engine hours. The meter says something +6000 but who knows. The engine itself does not have any problems. No loss of oil - nothing - at 1800 rpm workload.

And I never ever will change it! If needed I will do a complete refurbish to get a new engine!

Yes of course we all face problems like broken heat exchangers, mufflers, starters, pumps and so on but all these things have nothing to do with these good old engines.

[Scubaseas]

Some good suggestions here. There are a couple of things you can do to pin it down. One would be to take an oil sample for ananlysis and the lab can tell you if the milky oil is due to salt water or antifreeze.

If the issue is antifreeze in the oil you can verfiy this by filling the reservoir, start enigne with cap off and see if there are any bubbles constantly being generated when the motor is running. If you have a blown head gasket or a corroded head this is a common sign. Another way is to remove the injectors, pressurize the cooling system and see if any coolant comes out of the injector holes when cranked over.
Leaving the pressure on overnight is a good way to do it.

A pressure tester on the cooling system when the engine is running is also a good way to verify if you have a head or head gasket issue. If the pressure constantly builds when the engine is running you have proof positve the combustion gas it getting into the cooling jacket. There are also cheical test kits that can measure HC emmisions coming from a exhaust leak into th ecooling jacket. I used to use the State Inspection of r emissions machine to check.

Another method is introduce a flouresecent dye into the cooling system, run the engine for a while and using a UV light see if there is any trace in the combustion chamber or in the exhaust.

If salt water is in the oil it could be coming from a few places. The raw water pump does have a seal on the shaft that is supposed to keep water out of the crankcase and there is a weep hole in the pump so that if the water side seal goes, it leaks water through that hole and not into the engine oil. It's possible though I suppose. More likely a head gasket or corrosion issue as one possibility. Another would be the exhaust manifold corroded, Any oil cooler you have might be suspect although they usually also leak oil into the cooling jacket. Really anyplace where raw water and the oil can be found next to each other could be at fault. If your radiator cap works there is 14.7PSI presssure on the cooling system if the engine is warmed up and zero on any oil pressure gallery when the motor is off. If the milky oil is from salt water it can come from any place where oil is found in the engine next to the raw water system. Not sure if your mixing elbow could be at fault but they are a coomon problem on pretty much all boats. Look for the common stuff first.

[moseriw]

If salt water is in the oil...
Hmm nearly impossible as the salt water will not even touch the engine and I am keen to see how you will check this. I am sure even a taste will not bring any result. ;-))))

[Scubaseas]

Originally Posted by moseriw

If salt water is in the oil...
Hmm nearly impossible as the salt water will not even touch the engine and I am keen to see how you will check this. I am sure even a taste will not bring any result. ;-))))

Lab analysis of the oil would easily tell you if it's salt water or coolant.

How often do you check the oil? As in how long has it been milky?

A quick check of the coolant water side would be to fill the reservoir and run the engine. If you see bubbles your problem is not salt water getting into oil.

[sinnerman]

Agree with the blown head gasket theory.

The cooling system gets over pressurized as well from the leaking gasket and forces the coolant out of the system .

[jamhass]

A comment on the suggestion that the seals on the raw water pump is a possible issue:

The raw water pump on the 2003 does NOT directly communicate with the oil sump. There are 2 seals on this pump, one for the water side, another for the oil side. There is a large void between the two. Should the water seal leak, the water exits through the void, missing the oil side completely.

There is a small chance that the void can become fouled with slat such that a leak could make it to the oil side, but the hole is so large on this pump that it is highly unlikely that this would occur.

I have seen this happen on other engines, but the VP2003 pump has a very large drain void for such leaks.