1987 Mercruiser 165 Winterization

[Parker D]

I got a 1987 Four Winns 170 Horizon with a MerCruiser 165 I/O closed coolant system. I am getting ready to winterize it for the winter. This is the first time owning a closed coolant system. I have looked around and can not find any spots to open to drain water in the block. I'm not sure if you have to even do this with a closed coolant system, although the coolant in cooled by fresh water so i assume it has to be drained somehow. Looking for any diagrams or info on this. Thanks in advance.

 

[alldodge]

Being a 165 it was used from 1970 to 1981, did you mean to say 1978?

The 165 closed cooling has 2 plugs on the exhaust, could be 3 plugs in total if there is a riser block between the exhaust manifold and elbow.



Next pull drain plug on bottom of heat exchanger. Remove plug on power steering cooler if it has a plug, otherwise remove hose and drain

 

[Parker D]

I think you are thinking of the Inline 6 cylinder 165. I have the 4 cylinder 165 with the power steering cooler on it as well.

 

[alldodge]

Oh the 3.7, ok

Similar things happen





Saying drain the power steering cooler and heat exchanger. Also says to remove HE end caps to make sure all water is out and clean tubes as necessary

 

[Parker D]

well shoot that is easy enough. Thank you