5.4 questions...

[b1pig]

i realize this isn't a offroad rig... buuuutttt....



i got a 2008 expedition i drive at work. its had the front of the truck taken apart twice. once to replace a cracked radiator, and the second time to replace a cracked transmission cooler/condensor. (as it was explained to me)

the cooler was replaced in June due to a transmission fluid leak. since that repair, the truck has been "loosing" coolant. i've had to refill the tank a few times with water and the mecanics have had to put coolant in it twice now. there's no leak anywhere, and the HOAT crap thats in it leaves nice white looking trails wherever it does leak from.... to i'm thinking blown head gasket.


while sitting idle, the CHT will climb up to 230*. 3 days ago, i was stopped behind another vehicle for about 8 minutes. when i drove off, the fan stayed engaged, which it almost never does. CHT was 240*
once it got moving, the CHT came back down to the 220's... and i later checked the coolant level. tank was empty. i might have put half a gallon in it. since then, i've had to put almost another half gallon of water in it.

thats a bunch of water.

oil is clear. i've seen no steam from the exhaust at startup. is there anything else i'm missing?
there does not appear to be a heater core leak (front or rear)

only thing left i can think of is the head gasket, but i've honestly not heard of this much from the 5.4 engine. we've had a few let go on the 4.6s we've got, though....


83,400 miles on it. i drive like satan on a warpath.
got what sounds like a little bottom end clatter below 1,000 rpm and light load/part throttle too.

[dieselboy740]

Any coolant smell of you don't use the ac for awhile? Could be a minor heater core leak that gets washed away and dilluted by the ac condensation.

Or the intake is leaking.

[b1pig]

Originally Posted by dieselboy740

Any coolant smell of you don't use the ac for awhile? Could be a minor heater core leak that gets washed away and dilluted by the ac condensation.

Or the intake is leaking.

no. no odors. i haven't noticed any increase in condensate from the drain at either end of the rig. something to consider, though... i'll watch it the next couple of days.

my intake has the metal neck. i remember the crown vic 4.6 kept cracking manifolds when they were all plastic. i've looked, but haven't seen anything wet, or that whitish haze from a leak.... i'll stick my mirror tool up in there tomorrow and see what i can find, too, though. if you've got any other location, or just up at the front of the manifold?

[hart7290]

Check the trans fluid. I've seen a brand new radiator have an internal leak into the trans cooler lines.
If not, next step is to pressure test the cooling systom.

[Dr.Danger]

Originally Posted by hart7290

Check the trans fluid. I've seen a brand new radiator have an internal leak into the trans cooler lines.
If not, next step is to pressure test the cooling systom.

A buddy's Chevy leaked coolant into the transmission cooler lines after he used a corrosive radiator flush. Destroyed his newly rebuilt 700R4 as well.



OP, you need to do a cooling system pressure test. It'll force it to leak somewhere. Remove the plugs when you do, in case a cylinder decides to fill up. Listen for hissing noise as well as watching for leaking coolant.

[Hayes23]

Thanks for sharing.

[1sicbronconut]

Originally Posted by Dr.Danger

A buddy's Chevy leaked coolant into the transmission cooler lines after he used a corrosive radiator flush. Destroyed his newly rebuilt 700R4 as well.



OP, you need to do a cooling system pressure test. It'll force it to leak somewhere. Remove the plugs when you do, in case a cylinder decides to fill up. Listen for hissing noise as well as watching for leaking coolant.

Pretty much sums it up if the cooler that is internal to the radiator leaks you'll have what looks like a strawberry milkshake in the degas bottle. Despite some of the other problems they have I haven't seen a 5.4L or really any other of the mod motors with head gasket concerns that I can remember (Ford tech 24 years)