2005 base. I replaced my AC compressor and condenser, and as part of that process removed the water pump and drained all the coolant. I flushed the system, put on new water pump gaskets, and added DEXCool coolant. The manual and online says it should take about 3.1 gallons.

It drove OK, but after about 40 minutes of driving in about 90 degree weather, overheated. Prior to the last 5 minutes or so, it was sitting one tick mark under 220 degrees F.

I let it cool, and added about 1 gallon of coolant. Got home, and it was starting to overheat again (about a 30 minute drive).

When I first added the coolant after flushing with water, I ran the heat on 90 degrees, held the revs at about 2500 rpm for a ffew minutes, at intervals. I did this after recharging the AC system.

Yesterday, the first time I drove it since the overheat, I made sure coolant level was right below the max line, cap on securely. I drove about 20 minutes or so. I did not overheat, but it cooled down a few hours later, the coolant was pretty low again. This same cycle has repeated about 2 or 3 times, after like 20-3 minutes of driving.

There are no coolant leaks under the car at home or at my destinations. There is no sign of wet coolant anywhere under the hood or car. All radiator/water pump hoses are secure, in good condition with no visible signs of wetness after an overhear condition.

I have added about 5 gallons so far to this closed system, and do not know where it is going. When it overheats, there is no steam or anything, my eyes have been glued to the temp gauge, and I pull over right away before it hits the red mark.

Any ideas??

 

Well it looks like you followed the static fill method that is in the FSM…maybe still air trapped in the system…better to do a vacuum fill so no air gets in…you can get these kits on Amazon for between $50-$100.

 

[QUOTE=ShadowVampyre;1606724912]2005 base. I replaced my AC compressor and condenser, and as part of that process removed the water pump and drained all the coolant. I flushed the system, put on new water pump gaskets, and added DEXCool coolant. The manual and online says it should take about 3.1 gallons.

It drove OK, but after about 40 minutes of driving in about 90 degree weather, overheated. Prior to the last 5 minutes or so, it was sitting one tick mark under 220 degrees F.

I let it cool, and added about 1 gallon of coolant. Got home, and it was starting to overheat again (about a 30 minute drive).

When I first added the coolant after flushing with water, I ran the heat on 90 degrees, held the revs at about 2500 rpm for a ffew minutes, at intervals. I did this after recharging the AC system.

Yesterday, the first time I drove it since the overheat, I made sure coolant level was right below the max line, cap on securely. I drove about 20 minutes or so. I did not overheat, but it cooled down a few hours later, the coolant was pretty low again. This same cycle has repeated about 2 or 3 times, after like 20-3 minutes of driving.

There are no coolant leaks under the car at home or at my destinations. There is no sign of wet coolant anywhere under the hood or car. All radiator/water pump hoses are secure, in good condition with no visible signs of wetness after an overhear condition.

I have added about 5 gallons so far to this closed system, and do not know where it is going. When it overheats, there is no steam or anything, my eyes have been glued to the temp gauge, and I pull over right away before it hits the red mark.

Any ideas??[/QUOTE Goggle burp coolant system c6. U have to be adding wrong. Don't make any sense or its dumping coolant that u dont know about.

 

Well, I just topped it off with 1/4 gallon of distilled water, and drove 30 minutes. not overheating, but when I got home, I opened the hood, and saw water/coolant leaking from what looked like the overflow hose. See short video attached. I also heard gurgling sounds coming from resevoir and radiator area, or the T hose, hard to tell. Water drained to the ground. I havent moved the card, but guessing maybe 1/4-1/2 gallon. I also smelled coolant.

Prior to driving, I blew thru a piece of 3/8 fuel line hooked up to the overflow tube of the resevoir tank, with the t connector hose loose, finger on the T part, rag under the hose going to the heads. No bubbles or anything, just straight coolant coming from the hose.

What is going on ???

 

Determine the nature of that hose leak. The principal variable that prevents boiling is pressure, not antifreeze. Fix the known problem first.

 

In your video, the threads of the surge tank filler neck are visible. The cap isn't tightened.

If the cap is loose, the system can't pressurize. At atmospheric pressure your 50/50 coolant will boil over at 223°F.

 

Wow, good eyes.

Agree. That is why it is boiling over and coming out of that overflow pipe. Likely, most of the coolant you were adding boiled out while you were driving.

Tighten down the cap until it clicks. If it is still boiling over, you likely need a new cap.

As for filling the system, I have found that I can almost completely fill the entire cooling system and have very few air bubbles trapped. Temporarily take off the small hose that goes to the side of the reservoir closer to the front of the car. Use plastic funnel that you can insert into that hose, raise the hose up as much as you can, and add coolant to that. It is a little bit slow but it will push nearly all of the air out the system. When you cannot add anymore coolant, quickly re-attach the hose, fill the reservior to the line, tighten the cap and run the car to temp. After that, it should only require a small amount of coolant to get to the fill line.

 

Well, I did see the coolant cap, and have been doing it that way since adding coolant ( and overheating). I thought once down for the O ring would be good enough, my mistake for sure!
It is screwed down all the way now.

I also took off the front reservoir tank hose and filled with coolant and funnel as described above.

I ram in the driveway for about 10-15 minutes going up to 2500 rpm at times. It got close to about 218 or so, no issues.
I then drove it pretty good for about. Half an hour. Got home no issues!

hopefully it truly was just the loose cap, easy fix!

Thank you all so much!