SailNet Community - View Single Post - 2003 Yanmar, 765 hours - milky oil, overheating, evacuating coolant
View Single Post
  #1  
Old 05-10-2010
vpo3 vpo3 is offline
Junior Member
 
Join Date: Aug 2006
Posts: 6
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
vpo3 is on a distinguished road
2003 Yanmar, 765 hours - milky oil, overheating, evacuating coolant

Hello everyone,

My relatively new Yanmar 4JH3E was unused for 3 years and has just been put back into service and has a problem: milky oil and overheating.

Before I started the engine the first time, I changed the raw-water impeller, the radiator cap, the thermostat and the pump/alternator drive belt. All the old parts were in good shape upon removal. Basic maintenance is the limit of my knowledge and ability - but I've always been good about doing it on a timely basis.

After launch, the engine overheated. Part of the overheating was evacuation of coolant: about a quart (of a total capacity of about 7 quarts) got pushed out of the engine and then the overheating happens quickly.

There is liquid in the oil - very milky. I've changed it each time as I've re-tested the engine and it gets milky again. It takes 20-40 minutes before the engine overheats (the gauge spikes to max in just a few seconds). The engine is now very hard-starting: you turn the key and there is a long pause as the starter tries to turn the engine and takes a few seconds to overcome the engines resistance to wanting to turn.

Any ideas of what the most likely problem is?
Reply With Quote Share with Facebook