Oil and water mixing mercruiser 4.3 v6 (190) mil - Maxum Boat Owners Club

Marty87 · 05-10-2017, 04:01 PM

Hey guys I have cream paste in the head of my mercruiser 4.3 v6 (190) vortec but not mixing in the sump I'm thinking head gasket but looking for a second oppion

Kevlar7r · 05-10-2017, 04:08 PM

What is your operating engine temp? I had this happen on an engine where the thermostat was stuck open and the engine was running ice cold. It wasn't hot enough to vaporize combustion blowby and the moisture was condensing in the valve cover breathers. No evidence of water in the oil pan. Changed the thermostat and it was all better.

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Marty87 · 05-10-2017, 04:17 PM

I just replaced both thermostats and they operate at 160 degree and when engines are operating they sit at 175 degree on both engines

Marty87 · 05-10-2017, 05:07 PM

Rocker cover off and showing mixing but not mixing in sump

mmwjr · 05-10-2017, 05:29 PM

Not good!

The return passages are blocked so nothing getting back to the pan. Do both sides look this way?

mmwjr · 05-10-2017, 05:30 PM

BTY a blown headgasket will result in low power and the goo in the pan as well. Have you pulled the spark plugs to look for water in the cylinders?

Marty87 · 05-10-2017, 05:45 PM

Yae both sides

Marty87 · 05-10-2017, 05:46 PM

Nope haven't checked spark plugs yet

mmwjr · 05-10-2017, 07:00 PM

Pull the plugs to check for water. Pressure test the engine by removing the t-stat hoses and blocking them off and one having a fitting to install a air pressure gauge and fill valve. Add 8 psi of air and let it sit to see if it hold pressure not.

Rubber hose and PVC piping and caps are a good way to do this.

mmwjr · 05-10-2017, 10:30 PM

BTY the oil system is connected throughout the engine so these is goo in the pan as well. Are you seeing clean oil on the dipstick? Has the volume increased above the full line?

Marty87 · 05-10-2017, 11:08 PM

Oil pan is clean no mixing it's nice clean oil and level is gd

mmwjr · 05-11-2017, 02:34 AM

Quote:

Originally Posted by Marty87

Oil pan is clean no mixing it's nice clean oil and level is gd

Oil that gets pumped to the top of the engine drain into the pan and will carry the goo with it. Good news is you caught it before it containiated the pan and hence was pumped onto main bearings. The problem is how did water get to where it's at. Head gasket is seal between block and head so if it failed coolant would be in the cylinders and can leak internal and external the engine, compression test will answer this. A leaking intake manifold would leak coolant into lifter valley which is direct access to oil pan, so coolant would be in the pan. Bad exhaust would result with coolant into the cylinders and leak past the rings into the oil pan. I just cannot think of how coolant is contaminating oil on the top of the heads and be everywhere else in the oil system, lifter valley and pan.

Do a compression test and then a pressure test of the coolant system before disassembling the engine. IMO if you remove the intake and find goo it's in the pan even though it's not showing on the dip stick.

speedysprocket · 05-11-2017, 11:44 AM

So I ran one of my engines all last season with the white stuff on the heads but dip stick always looked clean, even though the level would go up.
When I brought the heads in to be rebuilt, he looked at the gaskets and said both sides had blown. I said I believe it.
And when I pumped the oil out, I then saw all the water. I think it must be the way the boat dip stick tubes go all the way to the bottom of the pan that may mask watery oil.

Marty87 · 05-11-2017, 12:30 PM

Spoke to a marine mechanic today and he reckons it's a cracked head my plan now is to clean it all on both sides put oil flush threw it and then put fresh oil in it and clean all breather tubes,

shrew · 05-11-2017, 03:12 PM

Quote:

Originally Posted by Marty87

Spoke to a marine mechanic today and he reckons it's a cracked head my plan now is to clean it all on both sides put oil flush threw it and then put fresh oil in it and clean all breather tubes,

If it's a cracked head, then I would assume you could see the crack. I'd like a visual comfirmation of the root cause. cracked head is much more severe than a blown gasket.

mmwjr · 05-11-2017, 03:23 PM

Quote:

Originally Posted by Marty87

Spoke to a marine mechanic today and he reckons it's a cracked head my plan now is to clean it all on both sides put oil flush threw it and then put fresh oil in it and clean all breather tubes,

Are you planning to pull the heads and have them magufluxed to look for a crack?

bman440440 · 05-14-2017, 06:35 AM

my 2c... I think you do have water in your oil pan... the oil in the dip stick tube doesn't really get "moved around" during normal operation.... there is no "flow" so the oil that is there will stay there... I know this from experience... I messed up and did not replace my risers in time and got water into the cylinders and from there into the oil... but the 1st time I checked my oil when I noticed I was having power issues the oil looked perfect... it was NOT... I decided to do an oil change and low and behold the first few ounces of oil looked fine (I use a vacuum extractor) and the rest was milkshake!! its just how those dipsticks are