I want to start by saying that I did a search and found people with the same issue but no definitive answer. Also, I do not think there is anything wrong with my truck, but just want some reassurance here. Lol. Approx. 2 weeks ago I did a dump/fill of my coolant system. What I did was drop the lower rad. hose only and refilled the system with fresh 50/50 Ford Gold and Distilled water in an attempt to keep "fresher" coolant in the system. I did a distilled water flush/fill about 2 yrs. ago and did not feel a full flush was necessary this time around. I just plan on doing this drain and fill procedure every so often to refresh the coolant without having to worry about a flush "stirring up a hornets nest" because my deltas are currently good and I hope to keep it that way as long as possible. I filled the truck to the min. mark after the fill and had to add a little more the following morning after it cooled off to bring it back to the min. line (which I expected). This past weekend I pulled my trailer on approx. a 400 mi. round trip and about 2 hrs. out I popped the hood to check the coolant level and the bottle was almost empty (engine idling and up to temp.) and then shut it off to have some lunch. When I came back out I popped the hood again and the level was back to the min. line so I figured I had an air bubble that needed to work itself out. After arriving at my destination I didn't check the level any more because I was parked on a pretty good side hill. On the way home the next day I pulled off the interstate and checked the level again, the bottle was almost empty again. After arriving home I checked it again, almost empty again (engine idling and hot) After sitting all night the level was exactly where I filled it on the morning following the dump/fill. FWIW, my temps during the trip towing a 4,500 -5,000 lb. load were 200 ECT / 210 EOT at 65 mph. on relatively flat road. Also, my truck is not and has never puked and is not losing coolant but has always maintained a coolant level approx. the same hot or cold but now the level is lower when hot but returns to the exact same cold fill level. Do I still have air trapped in the system ? I would have thought that the 400 mi. trip and several heat/cool cycles would have worked out any trapped air but maybe I'm wrong. If it is air, what should I do to work it out ? Any info. or opinions are greatly appreciated!

 

Try relieving the pressure when you stop with the truck HOT and RUNNING. Do it VERY slowly and carefully with a rag on top of the bottle and see if the level stabilizes.

 

Thanks, I'll give that a try. Also, I need to add that I did run the heat full blast with the engine idling after my dump/fill when refilling the coolant and also left the heater running for a short drive just after filling but have not run the heater since. Do you think I should ride around with the heater on some more ?

 

My 6.0 came from the factory with a little clear sticker on my coolant bottle, It's almost rubbed off but i was able to read that it said do not fill above this mark. and the sticker is at the very bottom of thew bottle, nowhere near the min and max lines, so after i did some coolant work and filled the bottle half way, on a hot day she was puking coolant, I would let it cool top it off same thing the next day. That's when I saw the sticker and tried to match up the sticker location with the inside of the bottle and found, it's at the very bottom, but the bottle does go a bit deeper in the back, so i guess thats were they wanted the coolant, thats were I put it. and 2 weeks no over heating no puking coolant. I'm good with that but they couldn't do better than a sticker?

 

They put stickers on the old tanks that they had in inventory until the old tanks were used up. The new tanks have the molded min/max lines in the correct place with no sticker.

 

Mine has done the same thing for years. I have pressure tested the system and it holds fine.

I haven't had to add coolant, ever.

I did this video to show mine. And, the last part was sped up to show the coolant rising.

 

That's strange. Mine has always held a fairly constant level, hot or cold, maybe expanding up in level a little when hot to around half way between the min. and max. marks. Is it possible for air to be trapped in there for years and not work itself out? I wouldn't think so but who knows ?

 

It's just one of the 6.0 quirks. I can start and move mine a 100' and the level will jump or lower an inch or more. Done it since new. As long as it returns and I don't have to add fluid I've learned to ignore it.

 

Exactly. And a very small change in the level of the truck from front to back can make it change significantly too.

 

That is strange indeed. Mine has never done this before, I wonder why it would start all of a sudden. Agreed on the truck needing to be level. The shape of the degas tank makes a little bit of a lean make a big difference in the perceived level. I park my truck in the exact same spot at the house all the time and it always returns to the same spot when cold. Guess I'll just have to learn to ignore it too. I may spend some time with the heater on and the windows down and also try slacking the cap under pressure as partsman suggested. Thanks to all for the input!

 

An air bubble will cause it to do that.
The top hose has a high spot in it that
will trap air and there are more spots
that take time for it to work out.

Best way to fill is with something like the radvac.


Sean

 

I have heard that you were "supposed to" use one of those to fill the system but I also saw everyone here on the forum filling without one. If it won't hurt anything I will just keep driving it. I would think it will work it out eventually. If ya'll think it could cause damage (hot spots, etc.) then I will have a trusted shop drain and fill it again for me with the vac tool. I just really prefer to do all my own maint. on the truck myself so I know it is done RIGHT!

 

It hasn't worked it's way out in the nine and a half years I've owned the truck wether I filled it or a shop. As stated before, it's a 6.0 quirk. The anomaly's are the trucks that don't do it. If your not adding fluid, just enjoy the truck. It's not hurting anything.

 

I appreciate it. I'll do what I've been doing since I bought the truck new, keep drivin' and smilin'.

 

Same thing here, i actually have a sharpie mark on my bottle where the coolant always eventually returns too...its rarely there, but on that one day when its parked perfectly flat and has been sitting a while, thats where it goes lol