Coolant change

[epricedright]

I replaced my coolant (50/50 green w/ distliied water), upper and lower radiator hoses, thermostat, upper thermostat housing and radiator cap a couple days ago, and was curious what the correct procedure is for adding the coolant. I did basically as the FSM stated, by adding coolant to below the neck in the radiator, started car without the cap on and turned the heater on. After the thermostat opened, coolant started over flowing out the neck. Then the level in the radiator would go way down, I'd add coolant again, and it would then overfolw again. I was able to capture most of the overflow with my anti-freeze tester (using it like a turkey baster), but I did lose a half gallon or so to the floor of my garage. I imagine I lost some of the 2 tubes of bars leak as well. I've let it cycle a few times by driving it and have added coolant to the rad and surge tank while cold, and I'm close to having my level right now.

I'm wondering what caused it to overflow - the air being purged out of the system or ? Would I have been better of putting the cap on before the engine warmed up? I'm wondering if the air in the system would have been purged out if I had left the cap on. I'm also wondering if I should add another tube of bars leak.

The FSM said to leave the cap off, and I couldn't find any previous post here regarding coolant change procedures for the 4.9.

Maybe if we can post the correct procedure, the next guy won't have to go through what I experienced and make a mess by wasting coolant.

Oh, btw, I was able to loosen the plastic radiator drain cock with my hand, so no homemade broomstick tool was necessary.

[adallak]

I would not fill the radiator to the neck if the cap is not there. If you underfill the radiator say, by some 2 inches it won't overflow when the thermostat opens and the trapped air starts moving around.

I usually fill it to the neck , start the car and drive it say, to a grocery store. Then I let it cool down and add coolant to the radiator and surge tank. One may need to repeat this procedure a couple of times before all the air is out. The cooling system of 4.9 is very effective. You can drive with half empty radiator and still will not overheat even in stop and go situation. Mine was half empty because of a cracked end tank, and I did not even notice that before I opened the radiator some day. LOL

BTW, turning the heater on does not make any change, since it does not affect the flow of the coolant through the heater core. I was told it made difference on older cars.

You might want to add a half of tube of Bar's Leaks through the radiator neck when engine is cold. It will not clog anything.

[epricedright]

After it over flowed and the level went down, I filled it to about 2 inches below the neck, and it then overflowed again. I then turned the engine off a little while later, and then it really overflowed. No big deal, but I figured there had to be a better way. Luckily I backed it in my garage and was able to hose the coolant out of my garage, but next time, I'll be sure to do it out in the driveway.

After adding coolant, did you replace your cap right away before starting the engine and before you drove it to the store, or did you drive it with the cap off? Will the air get out of the system by going into the surge tank with the cap on you think?

Should the final coolant level be right below the rad neck, with coolant at the cold mark in the surge tank when it's cold? I'm also noticing the level is not rising to Full Hot mark when it's hot. Does it typically rise to that mark when hot, then lower to the Cold mark when cool?

[adallak]

After it over flowed and the level went down, I filled it to about 2 inches below the neck, and it then overflowed again. I then turned the engine off a little while later, and then it really overflowed. No big deal, but I figured there had to be a better way. Luckily I backed it in my garage and was able to hose the coolant out of my garage, but next time, I'll be sure to do it out in the driveway.

After adding coolant, did you replace your cap right away before starting the engine and before you drove it to the store, or did you drive it with the cap off? Will the air get out of the system by going into the surge tank with the cap on you think?

Should the final coolant level be right below the rad neck, with coolant at the cold mark in the surge tank when it's cold? I'm also noticing the level is not rising to Full Hot mark when it's hot. Does it typically rise to that mark when hot, then lower to the Cold mark when cool?

First, are you sure the air did not get into the water pump? That would cause a lot of problems since coolant would not circulate. I do not think it happened if you just drained though. But if it did happen, you might want to add some coolant through the heater hose (just disconnect it from the plastic T).

1. I never drive with the cap off.

2. Yes, the only way the air will go out (and it will do so) with the radiator cap on is through the surge tunk. It may empty the surge tank (after cooling down and sucking the coolant back to the radiator) if the level is low enough.

3. Yes it will rise to HOT mark if it was at COLD mark , but only if it was really cold (ambient temp.) and engine was really hot (about 200F).

4. Yes the cold coolant should be right by the neck (you even will spill some when open the cap) and the level in the surge tank should be at the COLD mark.

I would not worry if the level were not EXACTLY at the mark. The inportant thing is just making sure it maintains the same level there when system is finally airfree.

[BodybyFisher]

I used to fill the radiator to the neck slowly (with 50/50 mix using distilled water) and wait for all bubbles to stop and the level to stabilize. Flush out bottle, fill to cold mark. Then I started the car and ran it till the thermostat opened indicated by the level dropping quickly and motion through the core, then I put the cap on loosely to avoid a spit back and turn the car off immediately, top off the radiator and put the cap on. Then I started the car and idled it for about 15 minutes till normal operating temp then I shut it off and allowed the cooling to pull coolant out of the bottle. I keep an eye on the temp by the way, if it goes beyond normal I shut it and let it cool, it will sometimes do that...top off bottle to cold mark.

My first trip was a very short one watching the temp letting it run at normal temp, staying near home in case it spikes, bring it home let it cool. top off bottle to cold mark. Done

[Ranger]

When you run the engine without a cap, the coolant expands as it heats and then boils sooner as it is not under pressure. Just fill the radiator to the top and fill the overflow reservoir (no surge tank on the 4.9) to the cold level. As it heats up, any air in the system will be purged into the overflow reservoir since the cap is the highest point in the system. As it cools, coolant will be sucked back into the radiator to replace the air that was purged. You may need to top off the reservior once or twice. I think I just said the same thing as adallak & BBF in a different way.

[epricedright]

Thanks everyone! I sure wish the FSM would have said to do it that way. I couldn't find any previous post here either referring to adding coolant to the 4.9. I guess I figured wrong that the air would have to come out the radiator neck. Oh well, no biggy....job's done!