Yesterday I noticed that the 02 EXP 5.4 was leaking coolant, enough to start dripping on the carport...we had to run into town so I checked on it when I got back it was a more steady stream.
Its leaking at the seam on the overflow tank, I take the tank out and and apply a thin bead of silicone hoping to hold the leak till a new tank comes in.
I fill the tank back up and take off to town. Suddenly the needle registers Hot. The Fluid level indicator light comes on, and the Service Engine Soon. I was close to home, so I limped it there.

I get home there is fluid all down the side of the truck, and underneath the carrage. It looks like the source is that dang overflow tank.
But admist the leaking it spprayed right onto the air intake, which apparently wasnt latched good on the bottom, so it sucked some coolant into the motor. Thus the reason I went from power, to 0 power.

Anyone else see an overflow tank leak at the seam like that? Also I am hoping the lack of power suddenly, and misidled etc was due to the moist MAF, etc.
I started the truck after drying it off some and seems ok, but still sounds a little weak. The wife said she has noticed less power over the past couple weeks and I agree with her. When trying to pass on the interstate its like I'm running a 6cyl.

I wonder if its a headgasket.....she has 182k on her but has been running great up to this point.

 

If its anything like the tank I have on my SD they are prone to leaking in those molded areas, mine started with a light crack but sealed it with a couple long beads of crazy glue until I get a new tank, been procrastinating though, its holding up great. About your power loss, a bump for yaa., good luck.

 

Thanks for the response. I'm hoping that once things dry out, and I put a new overflow tank in we might be ok.

It looks like the owner I bought the thing from put some type of orange goop in the overflow tank to try and solve the leak. Probably some type of radiator leak fix crap.

 

Someone correct me if I could be wrong here. Even if your overflow tank is cracked and you loose some coolant, you shouldn't be loosing all the coolant from engine/radiator. There will still be some left. You would only loose what is pushed out due to engine temp/pressure of the system. Coolant should still be full in the engine and most of the radiator. I think you may have another problem like a bad headgasket. Exhaust gasses are pressurizing the system, therefore, cracking the overflow tank. You shouldn't loose all your coolant because the tank is leaking and overheat. Just a thought about what is going on. Good luck - hope I am wrong on this one.

 

I agree with you, I dont know how much coolant was lost, but I was away from the vehicle for almost 2 months and my wife has been driving it. So it could have been leaking for some time now. I am going to fill the tank back up and see how it runs, it seems that it runs worse and hot after I fill up the resevoir.

admist all this the exhaust it clean, and I dont smell sweetness. *shrug*

 

You will not always smell it out of the exhaust and that is because the combustion gasses are being pushed out of the chamber into the coolant system and not the other way around so you will not smell it nor will you see any white smoke coming out the exhaust. These kind of leaks are sometimes not detected until it is too late and the engine has overheated and caused damage. I don't know how you could have gotten coolant into the engine from the overflow leak. What you said doesn't make sense. If the air intake system wasn't tighted down, latched, open, whatever, you would have had other problems show up because of the mass airflow sensor would be freaking out. Truck would have been running poorly if at all. CEL on? What codes? The best way by to check for a headgasket leak is to put the tube from a gas analyzer into the opening of the overflow tank and start up the truck and let it run for a bit. Don't let coolant get sucked into the tube. That will only damage the analyzer. If there is a bad headgasket and it is leaking into the system, your analyzer will start to show a reading. It shouldn't show anything. Another good indication is bubbling in the overflow tank with the engine running. Something to check.

 

Sorry a little more explanation on the coolant getting sucked in.

The joint where the airfilter is changed, was cracked open at the bottom which is before the MAF thus the reason it hasn't been noticed. However, when the overflow tank started to spray or whatever it did, it sprayed right onto the cracked opening and got sucked into the intake tube.
After that we threw a CEL.

I don't have a gas analyzer, but I will check for bubbles in the tank. Thats a good tip.

 

I've been smelling coolant on drives where I idle a bunch. Can't find any leaks, but there is one somewhere. Off the point, I know lol. Anyways, with the tank being pressurized, it doesn't surprise me that a little silicone didn't stop it from leaking. I'd try a new tank first, since you know it's a problem, then go from there.

 

So is the tank under some pressure during normal operations? I was under the impression that it shouldn't be under any pressure. But looking at the setup and the feed tube directly off the lower hose I guess it is apart of the main pressurized system.

 

This isn' tlike the old timey overflow tanks. These tanks are under the same pressure as the cooling system. (16 psi?)

In Ford speak, it is now refered to as the "Degass Bottle". It de-aerates the coolant, allowing any air to rise to the top of the bottle and only allowing liquid back into the engine when the engine cools down. Keeping air out of the system avoids hot spots along the coolant side of the cylinder walls.

In an 'emergency', as long as you don't run the engine too hard (read: keep it cool) you could loosen the coolant fill cap to keep the system from pressurizing. This could reduce the amount of coolant squirting out of the degass bottle until you get your new one. That is, as long as there is only a hair line crack in the bottle.