Ford Lehman raw water in oil

[C38]

I just checked my oil after using it may times and checking it. All has been fine till now. I had rebuilt the custom made heat exchange from Gustafson. The boat is a Nauticat 38. How can I clean the engine from the thick gray mess?

Thanks in advance

[Wotname]

Originally Posted by C38

I just checked my oil after using it may times and checking it. All has been fine till now. I had rebuilt the custom made heat exchange from Gustafson. The boat is a Nauticat 38. How can I clean the engine from the thick gray mess?

Thanks in advance

Assuming you mean 'thick grey mess' is inside the engine.

If so, first remove injectors so the engine can easily be turned over without compression.

Drain (or pump out) whatever gray mess you can.
Refill with clean (but cheap) thin oil and replace oil filter.

Circulate the new thin oil by using the starter motor for say 20 to 30 second busts and checking the starter motor temperature as you do so. A decompressed engine does not place a heavy load on the starter motor (or start battery) but you still need to check the temperature.

Change the oil and filter after several minutes of circulating the oil.

Repeat with another change of oil and filter.

Repeat (again) with another change of oil and filter.

When you feel happy enough that the grey stuff is well and truly gone, again fill with new oil (of the correct grade) and new filter. Refit the injectors, bleed and start.

Run under load for at least an hour to get everything up to temperature; check by shooting the oil filter temperature with an IR temp gun until oil temperature has stabilised.

Change the oil and filter again and monitor for say the next 50 hours.

Change the oil and filter and operate normally

[C38]

Yep. That is exactly what I mean. I was hoping it would be something like that and I didn't need to clean up by having to pull the engine.

Thanks

[C38]

I need to replace the custom heat exchange now with the more modern tube kind and have the oil and radiator fluid sperated instead of one like Gustafson did.

[Wotname]

Originally Posted by C38

Yep. That is exactly what I mean. I was hoping it would be something like that and I didn't need to clean up by having to pull the engine.

Thanks

Some suggest a flushing oil but I think the cheapest supermarket oil is sufficient.

I have been known to flood the sump and engine with diesel before using the oil but just because I have done it, I wouldn't be willing to recommend it others.

The trick is to circulate what ever fluid you use to push out (and dilute) the grey emulsified oil. The engine's oil pump is just right for this job!

[mvmojo]

Had this happen to me on a Lehman 80 due to an oil cooler breakthrough. I just drained all the water/oil mix out, added fresh oil & a filter and ran until hot. Changed the oil/filter again and ran until hot. Then changed the oil/filter one last time and went about my way, i.e., 2 oil changes discarded then use the 3rd. Put another 8,000 hrs on the engine before selling the boat, never a problem.

[aquafacts]

FYI -Same boat, same engine, same problem but it was the syphon break hose plugged with dirt from "mud wasps" where it exits the hull after being on the hard for awhile. Didn't need to pull injectors. Just flushed / changed oil many times and it was OK.

[C38]

Thanks for replies. I have an issue running the engine until hot because the engine radiator fluid is connected to the oil exchange. It is custom piece that Gustafson built and parts are not available. I am looking at buying the newer tube type exchange but have to redesign the whole system. Do you really need to cool the oil on the Lehman 80? I will change oil and filter after just cranking the engine just to get most if the grey mess out then figure out if how to get the engine exchange working so I can run it till hot and change again. I was thinking for right now just coupling the 2 oil lines together to bypass that to be able to run the engine but can't until I get the new engine heat exchange installed.

[Wotname]

Originally Posted by C38

............ Do you really need to cool the oil on the Lehman 80? I will change oil and filter after just cranking the engine just to get most if the grey mess out then figure out if how to get the engine exchange working so I can run it till hot and change again. I was thinking for right now just coupling the 2 oil lines together to bypass that to be able to run the engine but can't until I get the new engine heat exchange installed.

I don't know the answer but it is an interesting question.
I think it would depend a lot of how much power you are extracting from the engine.

For instance if you are only running at low rpm and say using <40hp continuous and have the occasional short (say <15 minutes) excursion to near max power, then I would think an oil cooler is not necessary. Likewise if you are using near max power continuously then it well might be necessary.

But rather than speculate, you could simply measure the oil temperature in operation by measuring the temperature at the surface of the oil filter (use a IR temp. gun). Typically the oil temperature should be about 10-15F higher than the coolant temperature. AFAIK, most oils tolerate temps up to 275F so keeping it below 260F is a good starting point.

If you find that you are occasionally approaching 260F when operating at higher power settings, you could fit an oil temperature gauge and/or a oil temperature alarm (audio and idiot light) and monitor it from the helm.

If you decide to try this experiment, do report back please as I would love to know the outcome!

EDIT: you need to remember there is no thermostat in the oil circuit some it will close monitoring will be required initially (IMO).

[Wotname]

^^ EDIT #2: the above numbers relate to non-synthetic oils. Using a full synthetic oil will allow for higher temperatures.

[C38]

Originally Posted by mvmojo

Had this happen to me on a Lehman 80 due to an oil cooler breakthrough. I just drained all the water/oil mix out, added fresh oil & a filter and ran until hot. Changed the oil/filter again and ran until hot. Then changed the oil/filter one last time and went about my way, i.e., 2 oil changes discarded then use the 3rd. Put another 8,000 hrs on the engine before selling the boat, never a problem.

How did you do this? I am assuming you fixed the cross contamination problem first? I an having an issue finding the correct size o rings to replace. I think that is why this happened. I had taken the exchange to a radiator shop to test and clean out. He said it was fine. I will bring back to test again. I only got about 20 hours on engine after working on it before this happened.