Milky Oil

B

buckhuntr1

New Member
Sep 1, 2009
21
CT
Boat Info
310 Express Cruiser
Engines
Merc Cruisers, twin 454's
OK. I need some assistance. I have a 1999 Express Cruiser, 454's fresh water cooled, in-boards. I started the motors last weekend and I had an oil slick running out of my through hull exhaust. I also found that I had some antifreeze in the bulge. I replaced about 3/4 of a gallon of antifreeze in the heat exchanger today. I pulled the hoses on my oil cooler and found it milky. The dip stick showed clean oil. I ordered and replace the oil cooler and found that I had also had milky oil by the oil filter confirming that I got water in my motor.

Today, I changed my oil twice and it's just as milky as it was when I started. My fear is that perhaps I now have a head gasket issue as well. I pressure tested the heat exchanger, and it dropped about a pound every 4 minutes but I could not find a leak.

Questions:
- Is there any way to test or figure out what is getting in the oil, water or antifreeze?
- The motor is running perfect, and I alway's believed that if it was a blown head gasket that there would be lots of steam and the motor would run sporadically. Is this true?
- I will pull off the raw water hose from the oil cooler tomorrow to ensure there is no oil in the water, but there's no oil slick in the exhaust so I'm assuming I'm ok there.
- What should be my next steps? Compression tests? Run the motor and see if I can find a antifreeze leak?

Any assistance wold be greatly appreciated!!!!

Thanks

Chris
 
How many hours on the engine?
 
It may be that your oil cooler rusted through and is pulling oil into it and through the coolant path and out your exhaust. Pull and check that first. Depending on what you find there will determine your next step. Hopefully that's what it is. If so replace it.
After that, perform a leak down test and see if you have solved your issue. Don't run the engine until you find out what it is first.
 
Could be a cracked head?
The antifreeze in the bilge could be overflow from expansion? Did you fill it right to the top and does it have an overflow tank?
Need to run it with the pressure cap off the heat exchanger and see if your getting bubbles ( blown head gasket at crush ring ) do it from a cold start and you won't get burned.
It could be a head gasket leak between an oil and a water gallery? You would expect to see oil in the antifreeze then as oil runs at a greater pressure 50psi than water 15 psi.
:smt089 either way, sounds expensive.
 
Here’s where I would start:

...Top off the antifreeze and pressure test. maintain 15 psi or so.
...Pull the spark plugs and compare with each other for abnormalities
...Pull the valve covers and look for signs of colored antifreeze.
...After all this time doing the work above (maybe 10 mins), crank the engine over with the plugs out to see what blows out any cylinders.


The above basic diagnostics test should give you a good starting point.
Let us know what you find....
 
Gerryb - 1250 hours

Nehalennia - I already changed the oil cooler. It had milky waster / oil throughout it.

Annie - I worried that it is a head gasket or cracked head. And yes, very expensive.....

Ron - Thanks I did pressure test the antifreeze and will follow your advise.

R.Blatter - she is a 310 ec. but it's the same exact boat as the 330. Just a different measurement of the waterline.
 
Pressure testing the heat exchanger you should not loose any pressure at all.

I bet elbow gaskets leaking cooling water into engine..
Drain the antifreeze / coolant and pull exhaust elbows and look in the manifold with a flashlight for evidence of a leak.
There should be no rust in the manifold...just a black soot coating.
Check condition of elbow (sometimes called a riser) needs replacement every fiveish years anyway.

if we still haven't found the problem...
Next, check plugs (mark all plug wires with tape and a number so you know where to put back) if water is get in a plug or two may look steam cleaned.
They should all look the same, slightly black with carbon...if you haven't run the motor much after winterizing they will all look oil fouled from fogging last year.
Next, all plugs are out check compression dry and wet.
Actual number isn't that important but, all should be within 10% of each other with a good strong battery spinning the motor.
If compression is low you almost found the problem but, now must pull heads to see............

Sorry for your troubles,

Good luck,
Mark.
 
I have the same problem, what did you find out, hudge oil slick behind boat , was it the oil cooler?
 
Chris,

I was thinking back to a small diesel engine I worked on once that blew the seal in the directly driven raw water pump and... to cut a long story short filled the sump up with water.... I remember fixing the seal and then flushing the eng about 6 or 7 times, running and changing the oil filter each time before we got it clean again..... Just a thought. If it's running ok and hasn't overheated to crack a head or worse maybe it was the oil cooler and it's worth having a few more attempts followed by a good run to boil off the remaining water? You would want to see an improvement as you go tho. All the best. Have a look at goody's thread above..
 
Goody,
I changed the oil pump and the slick went away. remove one of the hoses off the cooler and see if it's all milky inside. If not, then you don't have a leak in the motor oil cooler. Next step would be to check the transmission cooler. Good luck!
 
I replaced the trans cooler so its no that, i will pull off hose today and see what drains out , but it could still be leaking from above ? you siad you changed the oil pump? or oil cooler ?
 
for any one who cares it was the oil cooler, now to clean up the water oil mess through the engine, any ideas??
 
Glad you found the problem. Virtually anything else would have been far more expensive. I would also inspect the exhaust manifolds if they are original.

In regards to water in the engine.....the only thing I have seen that works is 3-4 oil changes in succession and revving a warm engine to 2500 rpms for a 3 minutes. Right now everything is coated with milky oil and the only way to get it out is to mix it with fresh oil and then pump it out.

-John
 
goodie,
Yes the oil cooler fixed the oil slick issue. Unfortunately it backfilled the motor with oil. I believed I resolved the issues yesterday. I drained the oil and then removed the filter and let it sit for about an hour. I then added 1 qt of oil and removed another 1 1/2 qt of milky oil. I added another qt and repeated the process. I then completed the oil change and ran the motor for 30 min. The oil looked good. I will go down tomorrow and change it 2 more times to ensure the salt water is completely gone.

Hope this helps.
 
Goodie, FYI, in all I will have changed the oil 5 times. Many mechanics told me 2 times was enough, but in my case it was not. Glad you fixed the issues. The next steps would have been very expensive!!!
 
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