Found the expansion tank completely empty

[PAExplorerXLT]

I gave the truck in near perfect working shape to my son about two months ago. Knowing how kids are these days and their abysmal lack of knowledge about cars, I tend to look over things whenever he stops by. Today I was checking the oil when I noticed that the expansion tank was completely empty. Not a drop of coolant. I quickly spotted the leak which was coming from around the thermostat housing (was replaced a few months ago and has a history of leaks). I asked if the car has ever overheated, to which he promptly answered no! So my question is this. How much coolant is still left in the cooling system if the expansion tank is empty and is there enough left to prevent overheating?

 

[Runnin'OnEmpty]

The expansion tank can be completely empty and the
radiator can still be nearly full. You can remove the
radiator cap to observe the coolant level. If it's within
a couple inches of the top, it should be OK with no
overheating. Add coolant directly to the radiator, and
then fill the expansion tank to the fill line.

Let the engine cool before removing the cap, to prevent
injury.

 

[PAExplorerXLT]

Hmm, I didn’t do that so we will never know if it was really low on coolant. As to the leak itself, the three bolts did take a quarter of a turn to tighten so may be that is all it takes to fix it.

 

[1997XLTRollover]

Hopefully that's all it is, but I've always had issues with those things leaking on the 5.0's. Not a lot, but just a drip every so often. Especially as they age and the aluminum corrodes and creates pits where it can leak out. Usually some RTV and a new gasket will fix this.

 

[Turdle]

I might add it is difficult to remove all the air from the cooling system. You should raise the front high enough to make the radiator cap higher than the heater core inlet hoses. Let the engine cool, and remove the radiator cap to fill the radiator.

with front still raised, Warm the engine with HVAC control set to Floor and warm.

After cool down, remove cap and top off again.

 

[PAExplorerXLT]

How much rise are we talking about? Curb height?

 

[Turdle]

I think it will need to be higher than that. More like 10-12"

 

[stretchman]

Chased a leak for a couple of weeks. At 187K thought the worst, head gasket, cracked block. Turned out to be a cracked thermostat housing (PLASTIC). Mech I talked to has replaced a bunch of them, What the heck was wrong with plain old cast iron?

 

[PAExplorerXLT]

Chased a leak for a couple of weeks. At 187K thought the worst, head gasket, cracked block. Turned out to be a cracked thermostat housing (PLASTIC). Mech I talked to has replaced a bunch of them, What the heck was wrong with plain old cast iron?

Do they make metallic aftermarket ones?

 

[swshawaii]

Do they make metallic aftermarket ones?

Is that plastic? Be careful. Did they make a metallic one?

Do you follow your posts after asking questions? See #17 and #19 .

http://www.explorerforum.com/forums/showthread.php?t=416538

 

[PAExplorerXLT]

Well, tightening the bolts wasn't it. The entire housing is “new”, as in 6 months so what could have gone wrong? Do I have to replace both upper and lower? Seems like changing the upper piece is a much easier job.

 

[swshawaii]

99% of the time it's the lower housing leaking from the seams or threaded sensors. Tightening over the 89 inch/lb. (7-8 ft/lb.) spec can also cause issues. Some have had problems with the aftermarket Dorman or Four Seasons replacements. If you need another lower housing, upgrading to the newer Motorcraft RH144 with threaded sensors is highly recommended. See post #10 above.

 

[PAExplorerXLT]

The leak is clearly visible in the seam between the lower and upper housing. Don’t see it anywhere else (it looks exactly like the link you gave). I just don’t want to start something I can’t finish although it looks simple enough. It is my son’s DD.

 

[PAExplorerXLT]

I was really tempted to change the upper and lower housings this long weekend but after an hour of poking around I realized it is not going to end well. Just too many things to unhook, disconnect or otherwise move around to be much fun. I could not see anyway to reach the three bolts without removing the black plastic intake cover despite pictures to the contrary. So, how much do you think a local mechanic is going to charge me for this?