mercruiser 3.7 strange water in oil question

[emcm0035]

Looking for any help on this got a wellcraft 192 classic which has the 3.7 in it. Stripped it down all new gaskets and seals runs first turn of the key now, my problem is that when connected to hosepipe on muffs the engine oil goes milkshake. But the water reservoir tank stays the same level no loss of fluid from it. I thought this is a fully closed water cooling system which is why has me stumped​.

Drive leg Is alpha one gen2 and has a leak at the top plate where you can check the fill level of the upper unit any ideas or whats best to seal it?

Any advice what and where to check is very much appreciated

thanks

 

[Bondo]

Ayuh,..... Welcome Aboard,.... That's an odd combo,....

The 470 was already in the history books, before the Alpha, Gen.IIs came out,.....

I believe yer water leak is the cam seal in front of the motor,....

The top cap of the drive, I believe is o-ring sealed,....

 

[stonyloam]

The only place the raw water could come in contact with coolant is in the exhaust elbow as it exits, doubt that is your source. Check to see if it is antifreeze in the oil, should be able to smell it. If it is than I'm with Bondo. Check to see if the weep hole on the lower starboard side of the engine water pump is clear. If someone plugged it to stop a coolant "leak" than you could be pumping coolant into the crankcase past worn seals. The weep hole is designed to let coolant leaking past the front seal leak out rather than being forced past the second seal into the crankcase. Let us know what you find.

 

[emcm0035]

Thank you for the help and advice. I replaced the cam seals that are in the water pump cover and the weep hole is also clear as I have just done full top end rebuild all torqed to spec as per manual. It starts as good as any previous mercruiser engine ive had in the past and idles perfect.
Previous owner seemed to not know a spanner from a hammer.

The coolant is still blue coloured just the oil is going white but without any water loss from the exhaust riser couldn't smell any coolant in the oil. Could it be a crack down in the bottom of one the cylinder walls?

​Thanks again for any more help and advice

 

[stonyloam]

Hmmm..... OK is the oil just white, or is it getting thick and milkshake consistency? It does not take much water to turn the oil milky. If you removed the head, might have got a little coolant in the oil. Happened to my diesel combine once, oil got milky for no apparent reason, changed the oil and all has been fine since. My suggestion, take a close look at the oil level, then run the engine up to temperature, see if the oil level and color change. If the oil is still milky, change it and the filter and run it up to temperature again, should be OK, I hope. Let us know how it works out.

 

[emcm0035]

I have tried the oil and filter change twice each time same result just milk color not any thicker it became thinner even more runny. Dipsick didn't show a level just had like water spots on it. no oil or milky color. but when drained just white coming out the sump pan drain plug hence why stumped. I have had mercrusier 3.0, 5.0 and 5.7 engines in the past and none to give headache like this

​When had the leg off to replace impeller and pump housing if started the engine the oil was as normal no milk or discolouration

Should just tear down the cooling system and riser and rebuild from there taking another look at the cam and the seals seeing if a speedy sleeves needed?

 

[stonyloam]

If the weep hole is clear and no coolant is leaking out when the engine is up to temperature then that should not be your problem. Look at the exhaust elbow gasket. Did you smell any antifreeze in the oil?

 

[Chisler]

Hello I've been following these 470 threads and I really appreciate it! I bought a 1983 with a 485 set up and found out that there is water in the oil when I drain the oil from the plug the oil separated out and it's water and oil there's no antifreeze in the oil. The guy that I bought it from claimed that it ran just fine the year before.

 

[GA_Boater]

Hello I've been following these 470 threads and I really appreciate it! I bought a 1983 with a 485 set up and found out that there is water in the oil when I drain the oil from the plug the oil separated out and it's water and oil there's no antifreeze in the oil. The guy that I bought it from claimed that it ran just fine the year before.

Old thread. Start your own.

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