Filling the cooling system - 470

[dccordell]

I drained all (or most) of the antifreeze from my 470 so I could replace it with fresh 50/50 mix. I followed the procedure from the manual to fill up the coolant system, but it seems that when I fill the reservoir 1" from the filler neck, and then crank the motor, as the motor warms up, the coolant level in the reservoir rises instead of falls as the manual suggests it should do. It states that as the motor warms, keep an eye on the level and keep it to within 1" of the filler neck. But mine starts to rise and eventually overflows out of the filler neck, so I have to put on the radiator cap.

Should it be doing this? I had expected the level to drop as the air bubbles were worked out of the cooling system, and thus the coolant level would fall requiring additional coolant. I feel like it needs to take a big BURP.

Also, after idling for several minutes, the temperature was about 180 and steady, according to the dash gauge and IR thermometer. I was using the IR thermometer to check the temps on the exhaust manifold, near the radiator cap and near the reservoir drain plug on port side. Does this seem reasonable for idle?

 

[agallant80]

Re: Filling the cooling system - 470

Uhmm would the coolant not rise? Heat expands, the tank is called an expansion tank. You reading that manual right?


The expansion tank retains coolant in a reservoir that's been forced out of the car's radiatior under pressure. As you run your car, the temprerature of the coolant circulating through the water jackets naturally increases causing increasing pressure in the cooling system. When the pressure builds to a high enough point, the radiatior cap allows that pressure to escape into the coolant reservoir through a small black rubber tube, called an overflow tube connected by the neck of the radiator to the expansion tank. Most of the coolant that is forced into the expansion tank returns to the radiator naturally after a few hours or when the engine is cold. If you had no expansion tank on your car, then the coolant that was released under pressure would spill out onto the road. It also helps by dissipating air bubles that have accumulated in the system. I

 

[dccordell]

Re: Filling the cooling system - 470

I never said anything about the expansion tank..

I understand how the expansion tank works. My issue is that, according to the manual, the coolant level should drop as air is purged from the system after the thermostat opens and coolant starts flowing. Even as the coolant heats up, the air should rise up and out of the reservoir (the part with the radiator cap), thus lowering the coolant level, until all air has escaped and the tank topped off with coolant.

Am I worried too much? The filling process didn't go as the manual suggests it should have, and that is what concerns me.

I guess if nothing else, I'll just continue checking the level after each run to top off.

Hoping to finally get this boat in the water within the next two weeks! :happy:

 

[agallant80]

Re: Filling the cooling system - 470

When you said reservoir did you mean the exchange unit? I think that is why I was thrown off. Any rate air pockets should work their way out. I don't know if yours has it but if you are really worried about it, there may be a bleed bolt on the top of the block.

 

[dccordell]

Re: Filling the cooling system - 470

No, when I say reservoir, I mean the part with the radiator cap. Isn't this called the coolant reservoir? I thought I had seen it called that in the manual. Maybe I'm mistaken...

I think I'll just run it and let it cool back down to check the coolant level. I just don't want to give this thing any reason to overheat, if I can help it.

 

[wrestling coach]

Re: Filling the cooling system - 470

I flushed and replaced the antifreeze in my 470 recently when I installed a 4" heat exchanger. I filled mine to the top of the neck and then started the engine.The level fell a bit and I added more while the engine was running. I replaced the cap and watched my temp gauge carefully run up to 160* and level out. In the meantime I added more antifreeze to my overflow tank. Not much. About a third full. Let the motor run for awhile and then shut it off. Left it for several hours to go cold. Removed the cap at that point and found the level to be right up in the reservoir tank and some antifreeze used from the overflow tank. Refilled the overflow tank to half full and marked it with a Sharpie. It has been that way since April.

Dennis

 

[stonyloam]

Re: Filling the cooling system - 470

Am I worried too much? :

I believe you are. Is the hose on the reservoir attached properly to the expansion tank? If it is, fill the reservoir as recommended, and fill the expansion tank to the cold full line and run it up to temp. Let it cool down and check the reservoir level, it should be full. If it is check the level of the coolant in the expansion tank, bring it up to the cold fill line and you should be good to go.
OOPS! Should have read dennis's post first LOL.

 

[dccordell]

Re: Filling the cooling system - 470

Sounds good.. thanks guys. I didn't get to mess around with it yesterday due to the crazy weather. The 180 degress while idling worries me, but I'll just have to see what it does on the water.

Thanks!

 

[stonyloam]

Re: Filling the cooling system - 470

The 180 degress while idling worries me, but I'll just have to see what it does on the water.

180 is well within the specs, it has a 165 thermostat. The main thing is does it stabilize at 180 or does it increase at wot? If the temperature continues to rise you have a problem. Couple of things, double check the temperature with another temperature gauge (IR thermometer works well), and if the impeller has not been changed in the past 2 years change it. Once you establish your correct temperature reading on the gauge, mark the face of the gauge with a sharpie and keep an eye on it. One other thing to do is to attach a garden hose to the water inlet on the exhaust elbow and turn it on to make sure the water exiting the exchanger can flow freely out of the outdrive.

 

[dccordell]

Re: Filling the cooling system - 470

Not sure on the steadiness of the temperature at this point. I haven't actually ran the boat in water yet, but hoping to in the next couple weeks. I have several small loose ends to tie up before she's ready. One thing after another it seems!

I did check with an IR thermometer. I wasn't exactly sure where to check with it though. I checked all along the exhaust manifold, from the front where the temp sender and alarm switch is, to the back. It was around 175-180 in most places. Is this the correct place to be using the IR thermometer?

I changed the impeller about two years ago, maybe a little more, but it hasn't been ran any since then, except for a few minutes here and there while I've been rebuilding the boat. I'd say less than 20 minutes on it since the replacement.

I'll do the water hose trick just for some reassurance.

At what temperature would you say I should get worried and shut down the engine, or at least back off to idle? If it normally run 180 in the water, but at extended WOT runs, it creeps up to 190, should I worry? At what point is a blown head gasket likely? 200?

 

[stonyloam]

Re: Filling the cooling system - 470

Normal operating temperature is 165-200 F (I would start to worry above 190). If it starts creeping up and continues to get hotter then you need to find out why. Check with the IR at the temp sender on manifold.