Antifreeze out the oil drain hole

[Mate Matthew]

Not sure if this is in the right section for this but don't thin k this has a section! Ok here's the scoop. Got a used 1979 with a mercruiser 470 in it. Had milky oil so i did a head gasket job on it. When i got it put back together i left the oil drain plug out as i filled the closed cooling system with antifreeze. Once the system was close to full green coolant began to trickle out of the oil pan drain. Wtf! Any suggestions at this point, other than to punt? Please help, I really like the boat but am at my wits end!

 

[kenny nunez]

You may a problem with the timing cover and water pump cam seal that was leaking before you purchased the boat. Was the head checked for any cracks?

 

[tpenfield]

It would be a cracked block (or head). Did you know for fact that the head gasket was bad? Milky oil usually points to a cracked engine block.

 

[Scott Danforth]

time to pressure check the block and locate the leak.

could be the cam nose seals for the water pump as Kenny mentioned. could be a cracked block. did you use a factory mercruiser gasket?

 

[Mate Matthew]

No used a after market gasket. never even started the boat so would of thought even a after market gasket torqued to spec would of held. I was leaning towards the water pump/timing cover. The head went to the shop was completely went over and received three exhaust valves. Thanks for the advice! keep it coming please.

 

[Scott Danforth]

only the mercruiser OEM gaskets work for that motor.

plenty of write-ups on replacing seals and speedy sleeving the cam.

 

[Mate Matthew]

If the seals on the water pump are out would I see coolant coming out of the weep tube?

 

[stonyloam]

I suspect that the cam seals are shot and the weep hole in the pump cover is plugged. See if you can locate the weep hole on the lower starboard side of the waterpump cover. There are two seals in there that ride on the cam. The weep hole is designed to let coolant that leaks past the first seal to drain out rather than being forced past the second seal into the crankcase. Sometimes some owners will plug that hole to stop the “leak”. Take a piece of wire and probe the hole, if coolant leaks out when you clear the hole your seals are bad. The OEM head gasket is far superior to the aftermarket, however the aftermarket could work just fine, just keep an eye on it.

 

[QBhoy]

Likely the head gasket needed replaced because the head warped (and the old dissimilar metal thing), because the water pump shaft seal is shot etc etc. Have a wee read up on these engines. Bit of a chain reaction and if not known about fully, sometimes the unaware spend far too much time being reactive instead of proactive with the faults associated with these engines.
All the best