High Temp Water discharge Mercruiser 3.0

[larson24]

The discharge at the drive is so hot you can only keep your hand under it a few seconds, the temp gage reads aprox 160-170 and the engine diesels a little at shut off. Is the discharge water temp normal for the 3.0? I have a 5.0 gl that is luke warm at discharge. Thanks for any ideas.

 

[tpenfield]

Re: High Temp Water discharge Mercruiser 3.0

It seems high. . . FWIW I actually measured the temp of the exhaust discharge water on my mercruiser, and it was about 85 degrees.

 

[fat fanny]

Re: High Temp Water discharge Mercruiser 3.0

I would seriously consider testing your temp sending unit,gauge and then onto replacing stat then impellar in the lower unit. M 3.0LX discharge is like warm @ best @ operating temp.

 

[achris]

Re: High Temp Water discharge Mercruiser 3.0

It all depends on whether the thermostat was open when you put your hand under... While the thermostat is closed (and this goes for any engine) the only path the water takes is through the exhaust elbow (for 'warm' manifolds) or the exhaust manifold and elbow (for 'cold' manifolds).

If the engine is running at 160?-170?, then the water coming out when the thermostat opens will be at that temperature. :facepalm:

My original Mercruiser 165 had very warm water on the flushers too.. Too hot to hold your hand under for more than a few seconds.... and that had a 'cold' manifold...