closed cooling drain options 5.0 mercruiser

[MTBoat]

My Mercruiser 5.0 has closed cooling to the manifolds and a heat exchanger that sits in front on the floor. I wish to drain any raw water..

1. Am I right to assume that if I drain both manifolds, and then open one end of the heat exchanger and leave it open for winter, that all will be well?
2. Is there any reason undo both end caps of heat exchanger, or other areas of water drain options that I am missing?

As the the antifreeze level of protection, its just a little weak; protects to minus 15 and I need about minus 35. Its good otherwise and fairly new, but,

3. is there an easy way to add straight stuff and get that protection level up without draining the entire system, i.e. is one of the hoses going to the heat exchanger that sits at bottom front of engine a good place to drain some out, and

4. if so, then where do I add the straight stuff?

5. I assume if I run it for a while it'l all mix together efficiently?

, i just didn't want to drain the whole system.

 

[Scott Danforth]

I would have to see a picture of your setup. definately not stock

in addtion to the manifolds, you will need to also drain the raw water lines and the power steering cooler

you always undo the ends of the heat exchanger to remove debris that gets in there at least once a season

no, you need to drain a good portion of the system to add more AF. your going to be draining about 1.5 gallons out

you will need to run it for at least 15 minutes

 

[HT32BSX115]

As the the antifreeze level of protection, its just a little weak; protects to minus 15 and I need about minus 35. Its good otherwise and fairly new, but,

It's pretty "standard" to have the coolant at a 50:50 mix. You know for sure that you didn't or someone else didn't?

If that's true, then just drain the system and refill with a 505:50 mix. And if it's been in there for more than 4 or 5 years, I would do a drain and fill anyway.

 

[MTBoat]

Thanks for the input, very helpful...I got this boat from a person further south,,,and now its in Montana, so cold is really cold here. But, I never did a power steering cooler drain before, or have seen it. Do all power steering units have a "cooler" and is there a plug or something to look for that is fairly obvious?

 

[Fun Times]

Do all power steering units have a "cooler" and is there a plug or something to look for that is fairly obvious?

Sort of need more engine info to try and help to either go off of memory or try to look up your exact cooling system.

Engine year, serial number, knowing if it's an Alpha or Bravo stern drive may help too. Being Closed Cooling, do you have an engine mounted sea water pump or if an Alpha stern drive, is the drives impeller cooling the engine or maybe both impellers are cooling the engine....< Things you'll want to know.

That mentioned, some power steering coolers offer a small brass drain plug at the lower bottom that you could remove while it seems most of the 5.0 models did not have a drain plug...If yours does not than you'd need to remove the hoses going to cooler in order to drain the water to help avoid an internal crack which could ultimately either put water in the oil or oil into the water....Just depends.... Some power steering coolers share as an engine oil cooler as well so you have to be extra careful there....Yours being a 5.0 shouldn't share though.

 

[Scott Danforth]

We are going to need photographs as the cooler described is NOT standard. OEM and aftermarket heat exchangers are mounted to the engine, not the bilge itself.

 

[MTBoat]

1. I am wondering if steering coolers are usually cooled with the closed cooling system of antifreeze or raw water? If closed, I should not have to worry...?
2. Actually, I looked all over the power-steering pump and saw nothing that looked like a cooler it was just oil in and oil out tubes like on a car...?
3. I drained a gallon and a half of antifreeze and added straight stuff and ran 25 minutes...I assume it should be very good for now and mixed throughout,,,the thermostat opened and I could add more to top off.
4. The only issue if the above are true is did I get all raw water out....I opened the drains on the manifolds both sides,,,and took off the end caps on the bilge level heat exchanger...and I think that's it as the rest should be antifreeze cooled....?
Its a 1993 5.0 with alpha one gen 2 with raw water impeller in leg....

Thanks for any comments or expertise....

 

[HT32BSX115]

Mercruiser systems frequently have the oil (if installed) and PS coolers in the raw water line prior to the heat exchanger......

 

[Bondo]

Mercruiser systems frequently have the oil (if installed) and PS coolers in the raw water line prior to the heat exchanger......

Ayuh,.... Agreed, on the raw water side, either at the back of, or under the motor,....

 

[MTBoat]

Found it but almost impossible to reach the power steering cooler under the port side and tight, tight engine compartment.
However, the heat exchanger actually sits below everything up front on the floor and when I pulled the end caps, I assume the cooler will drain by gravity out through the exchanger....so should not have to pull a hose in that impossible to reach area of power steering cooler..??