Winterize a 1993 7.4 Bravo Gen V

[ThomW]

Hey all. I've winterized numerous other Mercruisers, mostly smaller 3.0 engines. With the 7.4 is there anything additional I should do to ensure all the water is out?
No issues with changing gear lube, oil and fuel filters, oil, and winterizing the inside water system. My question is focused mainly on the engine block.
I know to pull the drain plugs, poke around to remove any debris, and I have a bucket I use to run anti-freeze through motor via a pair of ear muffs while its running, after I drain water.
Is there any additional steps I need to take? Like pulling hoses? removing thermostats? pouring anti-freeze into any hoses or anything like that? Do I need to do anything for this system specifically? Does it have a closed cooliong system I need to address?

Thanks as always!

 

[Bondo]

Does it have a closed cooliong system I need to address?

Ayuh,..... Unless you see a radiator cap somewhere in the motor box, the odds are pretty slim on that,.......

If yer gonna run it on an atifreeze solution,.....
After ya drain it 1st,......

No, there's nothin' more to it,.....

If yer gonna just drain it dry,..... Like I do,....
The only "gotcha" is the same on most of the Chevy V-motors,.....
The p/s cooler, under the portside forward motor mount, needs to be drained,.....
On some electronic motors, the cool fuel is there too, which needs drainin',....

 

[alldodge]

Does it have a closed cooling system I need to address?

You need to tell us if its closed cooling or not
Serial numbers are best

Drain seawater pump by removing hose

 

[Bondo]

You need to tell us if its closed cooling or not
Serial numbers are best, but the motor

Power steering cooler under the port side of the motor.

Drain seawater pump by removing hose

Ayuh,..... Good catch,........ I missed that one,......

 

[eric102]

On my 1992 7.4 closed cooled Gen 5:
- remove hose connecting seawater pump to oil cooler, its the lowest point in the system.
- it may not be necessary but I also disconnect the intake hose on the seawater pump and tick the engine over a few revolutions to ensure all the water is out of the seawater pump body.
- remove drain plug on oil cooler.
- remove drain plug on heat exchanger.
- remove drain plugs on exhaust riser blocks.

I don't fog the engine or run antifreeze through seawater side of cooling system.

 

[Bodean1]

Don't forget to drain the big hose on the circulating pump.

 

[ThomW]

Thanks everyone! Serial number is 0d845893.

What do I do to drain power steering cooler? Is that something I do only if I was not using antifreeze?

As far as plugs go--how many am I looking to remove?
I believe they are blue on these motors--but not 100% on that. it's a buddy's boat, so I haven't looked into motor too closely yet.

 

[alldodge]

Have not said if the motor is closed cooled (heat exchanger) or not??


Being a 93 it wouldn't have Blue plugs unless they where change to them by the PO. It would normally have 1/8 NPT brass plugs. The PS cooler will have a plug when removed will drain the hose coming from the seawater pump to the thermostat


https://www.mercruiserparts.com/bam/subassembly/31802/1621/160

Open cooling

Closed cooling

 

[ThomW]

I won't know if it is closed cool or not until I drive out there this weekend to help my friend and can look at motor myself. What would the differences be between the two, so I can be prepared for either case?
How many drain plugs should there be total?
is the plug on PS a brass plug like the ones on block/exhaust?
Thanks again for all the help and information.

 

[alldodge]

Closed cooling has a large tube across the front of the motor and has a radiator cap on it

Yes, the plugs will be the same as in the block