First of all I will like to say hello to everyone on this great forum! It is my first time posting. I am currently overseas in <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-comffice:smarttags" /><st1:country-region w:st="on"><st1lace w:st="on">Afghanistan</st1lace></st1:country-region> and my wife is having an overheating problem with our 99 Expedition 5.4L. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>
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The problem started about 2 months ago when the hot weather started back home in <st1:City w:st="on"><st1lace w:st="on">San Antonio</st1lace></st1:City> (100 to 105 degrees average). Under normal driving speed she noticed the truck running sluggish for a few minutes then noticed the temp. gauge in the danger zone. She let it cool down then drove it home (about 10 min. drive). The next morning I told her to check the reservoir and yes it was empty. It took about 1 1/2 gallon of 50/50 coolant water mix. <o></o>
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Before this problem started, I do not know when was the last time the coolant level was check since I been gone, my wife takes it to walmart for oil changes since its convenient for her, but she just found out that they do not check the coolant!! It ran fine for the last two months until last weekend when it over heated again, more fluids were added to the reservoir and its reading at the proper level, but the truck has not been used since it last overheated. It has about 114,000 miles and the radiator was flushed at 90,000 miles.<o></o>
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I had my wife check the oil on it and send me a picture, which to me does not seem to have water in it, it was actually reading on the middle of the window between low and full. But were has this coolant gone? What can be the easiest checks for her to do since I am gone? I can repair it myself if it’s something major like a head gasket but if its something minor then I can have a shop take care of it since I have about 5 months before I return home. I just don't want her to get ripped off!! I have heard about possible clogged radiator, bad thermostat etc. Were should we start?? Thanks to everyone in advance!!

 

First thing as you have said is to find out where the water is going. It is very possible that it is a head gasket. But that doesn't mean it will go right in to the oil pan. It could be going into a cylinder and out the exhaust. Neither of these is good for the long term life of the engine. If it is going out the exhaust and it is enough the exhaust will smell a little sweet. If it is going into the oil pan the oil will look like a milk shake. There is also a chance it is just leaking from the water pump or a hose or a heater core. It doesn' sound like a big leak where ever it is.

 

Just another thought, but if your wife doesn't see any major puddles underneath the truck you could have her check the reservoir daily and just keep it topped off. That might be the cheaper route until you get home and inspect it yourself.

 

I'd say there's a good 95% chance it's a blown head gasket.

 

I agree with Alloro it is most likely a head gasket.

 

Do you guys think this is related to the infamous 99 head that had the problems because it was machined wrong? I know that was mostly related to oil leaks but its just a thought.

 

Its possible, my 99 had the oil leak, no water leak but it is possible. It could still be some thing else but I am leaning towards head gasket.

 

I will like to thank everyone for the quick responses to my problem! <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-comffice:smarttags" /><st1:City w:st="on"><st1lace w:st="on">Omaha</st1lace></st1:City>, like you said it looks to be a small leak since it took over a month to empty the reservoir. Also the oil has no water in it and the dipstick, it does not look milky, it is actually reading on the middle of the notches. The truck has no leaks underneath from damaged hoses etc, but I will have my wife check the carped on drives and passenger sides to see if there is a leaky heater core etc.
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Now my question, this truck had never overheated until this problem started, is there a chance that there is a problem with a component of the cooling system which caused the head gasket to go, or are these models famous for blowing gaskets out of the blue! I will like to know in order to change some additional parts once I return home and verify that the gasket is the problem. I never had any problems with this truck until now, good thing I have a beater that the wife can drive for now. I don’t want to risk blowing a piston or creating any further damage to the engine. Thanks again guys..

 

If it is a leaky head gasket which is what it sounds like to me also, you might consider this stuff since you're so far away. http://www.steelseal.com/ By the way, keep up the good work over there.

 

Thanks Madson, this looks like a good solution. I was looking at the video and it will be great if it does what it claims, has anyone used it before or know of anyone that has?

 

99's and 2000's with the new PI heads had a problem in the factory where the passanger head was moved in the fixture before the grinding was done, shaving of more on the passenger head than needed toward the back of the head. A one month leak could still be anything. There is a hose that runs under the intake maifold that can leak, or one of the fittings connected to the hose, so it could still be some thing else like the heater core.

 

I will have her check everything for possible leaks etc, also check is the exhaust has water comming from it or the sweet smell! Thanks