closed coolant system, 1/2 system, winterize

S

stang32

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Jul 17, 2004
RO Number
14425
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56
ok, stupid question, but since i have a closed coolant system do i haveto run anti freeze through the raw water section or can i just drain it & it will be good?
yes the closed (engine) section is full of anti freeze
 
I would, as you may have water trapped in areas you cannot see. To me, it's a no brainer. Do it.
 
Yes, put AF into the raw water side. Draining it just leaves a lot of wet metal and that promotes a lot of rusty growth. Replace that water with rust inhibiting AF.
 
What I do is mix up my winterize fuel mix and run it thru the engine until the thermostat opens at that point you have flushed the raw water side good. I then drain the raw water out and hook up my winterizing bottle with the pink or purple anti-freeze and run it thru until it starts coming out the exhaust. That's it done.
Rob
 
quote:
Originally posted by Brite Idea

What I do is mix up my winterize fuel mix and run it thru the engine until the thermostat opens at that point you have flushed the raw water side good. I then drain the raw water out and hook up my winterizing bottle with the pink or purple anti-freeze and run it thru until it starts coming out the exhaust. That's it done.
Rob

Click to expand...


So, just how do you know if the T-stat is opened or closed?
Suggestion...take it out and that removes any possible error. It only takes a few minutes to remove it.
 
The thermostat is on the closed loop, how would waiting until it opens or taking it out have any effect on the raw water side? I take the raw water hose off of the heat exchanger and pour RV antifreeze in it as well as several other raw water hoses..........D..........
 
On a FWC engine, you are right. T-stat open or closed...doesn't matter.
I was replying Brite Idea's thread who said he ran his engine until the T-stat opened. The way he worded his post, I just assumed he has a RWC engine and on a RWC engine, the T-stat opened or closed does matter.

My question is still valid...how can you tell if a T-stat is opened or closed?
 
Correct on a FWC thermostat doesn't matter , but the OP is a split system AKA FWC so he does not need to remove the thermostat, he would need to pull raw water hoses and pour the pink stuff in the hoses like I do on mine. The way the thread was going just sounded as if he was being told to remove the t stat and wait for pink antifreeze to come out of the exhaust which it never will.

Also, if you don't have an engine room heater, make sure your heat exchanger raw water side has some antifreeze in it, there are small tubes that can trap water and it doesn't take much to break them............D..........
 
Why pull hoses? I helped my son winterize his 5.7 Merc. I had a 2-3 foot hose, connect one end to earmuffs and put a funnel in the other end. Crank up the motor, poured in 4 gallons of AF into the funnel and shut down engine when all the AF was sucked up. Done. I did remove his T-stat since the engine was RWC.
 
I have always been a bit Leary of doing that to mine, I took an impeller out once running it on muffs. I was told that with he bravo I to never run it out of the water.........D......
 
I like to flush the raw water side and since I mix a fuel cocktail for my EFI I let it run until the thermostat opens. You're all correct it doesn't matter thermostat open or closed. Everyone does it a little different but I will say that you should drain the raw water side before sucking up the anti-freeze or it will be diluted. I'm also more cautious because it drops to single digits here and if I mess up I loose an engine or two. I can watch my temp gauge and see when the thermostat opens.
Rob
 
I can tell when my thermostat opens also. Immediate temp drop. I think though that when you dump cold antifreeze into the mix, it closes. I've always been surprised by how dilute the antifreeze was in the block when my engines were RWC. So if you don't drain them before you run antifreeze, I think you should take the thermostat out. I always used to open one of the block plugs on each engine and drin some mix into a cup to test it. Didn't want surprises in the spring.
 
I have Volvo Pentas. No closed cooling. Drain block and manifold. Use a small piece of wire to clear rust out of holes to let water flow. Drain lower hoses and bump starter while hoses off to remove water in water pump. Mine also has a small hose to fuel pumps to drain. Put it all back together and pour antifreeze down hose coming off of thermostat housing until it comes out the other side. No need to remove thermostat, there is a small bypass. Finish second beer and play with GPS settings. Have third beer and leave the outdrives until next week.
Jim
 
Whether or not you drain the RW side, I think it a very good plan to run non-tox A/F through that side because drains may be missed or clogged . If you have mufflers , this protects them too, without draining, plus any sea strainers, oil coolers and low spots on RW hoses.

The FWC engine doesn't have to be warm or t-stat removed , since ,as was already pointed out that only affects the FW side .

Some non-tox even has desirable anti-corrosion inhibitors, but most boaters buy the cheapest they can find without the CI. Generally takes 5 gallons or more per engine until the fluid out the exhaust no longer looks diluted from full strength color w/ water. My winter-storage yard over in America does this on my T/I/B's

To make sure the closed-cooling FW side remains sufficiently winter-protected for your area, I suggest you also test the antifreeze if the A/F has not been replaced this year.
 
Sandy, is it sufficient to check the quality of antifreeze in the overflow bottle, or should you drain some out of the block and test that?
 
With a raw water cooled engine I'd always drain manually and backfill manually with -100 marine AF.
With closed cooling you can do the same for the raw water side; or rig up a winterizing tank with a bilge pump to pressurize the flow of AF. I think pressurizing the flow is more needed on engines with engine mounted impellers because these may otherwise not be able to self prime. With the impeller in the drive it is not as needed but probably still a good idea.

Keep in mind when you run on the water muffs the water pressure makes up for the hydrostatic pressure that pushes water into the drive when the boats in the water. Gravity flow may work with an Alpha because the impeller is right above the water intakes. However on a Bravo or Volvo doing it this way is likely to starve the impeller of AF because the AF cannot be sucked all the way up and forward. Impellers are designed to suck liquid not air.
 
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