97 Expedition 5.4L overheating problem

[Firekatt]

Hi everyone,

So I have a 97 expedition with the 5.4L and am having a problem figuring out an overheating problem. Mainly, I'm just asking for some advice from those of you that know these engines better than me. At first I thought it may be a stuck thermostat so I pulled it out and found very brown, rusty water inside. I put the thermostat in a pot of boiling water and it only opened a crack...not even a 16th of an inch. I figured it was bad so I flushed the engine coolant out (thanks to the previous owner who had put one of those prestone flush adapters in the heater line), added fresh coolant with the front of the truck up on ramps and ran it without a thermostat to see what it would do. Sure enough, the temp gauge started climbing rather quickly for an engine with no thermostat and after a 2 mile drive, was getting close to the overheat mark with no hot air out of the heater. My next step was to let the engine cool down. I then took the cap off of that flush adapter and hooked a short garden hose to it. I made sure the cooling system was full and started the engine and nothing came out of that heater hose. Not even a drop.

This is leading to believe that my water pump isn't pumping anything. I don't think it's a totally clogged radiator because I had a garden hose hooked to that flush adapter and the drain plug open on the radiator and water was flowing rapidly out that drain plug hole. Does anyone have any other thoughts on this before I go spending money on a water pump and more coolant?

Thanks in advance!!

 

[docraymund]

Try to inspect the upper and lower rad hoses for collapsed inner lining. If they are ok, your water pump's fins may have corroded necessitating replacement.

 

[Firekatt]

I just checked the hoses, as far as I can tell, they're not collapsing. I will pull the water pump this weekend to take a look at it and see if the fins are corroded.

 

[Firekatt]

Problem solved. I pulled the old water pump this morning and actually found that the impeller had broken off the shaft. It was laying in the hole in 2 pieces. Cleaned everything out and then flushed the system to hopefully get anything else out of the system, installed new pump and now feel coolant circulating through the upper hose once the new thermostat opens. Just got this truck and it had been sitting for over a year. Seems the previous owner had straight water in it and it froze over the winter. He told me he would go out and start it once a month but I'm guessing that he started it and the impeller area was frozen solid and that's what snapped it. Very lucky I don't have any leaks or a cracked head/block from it.

 

[1955moose]

Now you know why he sold it. Next time you suspect a bad water pump, pull the lower hose, fire the vehicle up. It should pump out the hose if all is well. Glad you figured out your problem.


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[stamp11127]

Plan on doing the heater core and radiator. These have a tendency to eat them if you use straight tap water for coolant.

 

[Firekatt]

Plan on doing the heater core and radiator. These have a tendency to eat them if you use straight tap water for coolant.

Thanks for the tip. I'll keep a very close eye on them. So far, I've driven about 250 miles and no problems. Temp gauge stays right where it should be.

Thanks to everyone for giving your input as well!!

 

[1955moose]

No problem, let's hope all is well. From your tag line are you a firefighter?


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[Firekatt]

No problem, let's hope all is well. From your tag line are you a firefighter?


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I was, I'm retired now though. 22 years on the Dallas FD and then moved to North Idaho to get away from the brutal summers. Still hot here in the summer but no where near the humidity that Texas has. My next project for this rig is actually the AC...but I have that narrowed down to the compressor clutch being bad. Put power straight to the Black/yellow stripe wire at the low pressure switch and nothing happened except a little spark when the wire touches the battery. Did it this way since the actual connector on the compressor is a pain to get to and see so as to not touch the ground wire terminal too.

 

[1955moose]

It might be a safer/easier bet to change out the compressor with the clutch in one piece. Just spend the $ and buy a motorcraft or top notch brand. The bargain ones burn out quick. Thanks for your service in Dallas.


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[rjdelp7]

Use distilled water in engines. Tap water has a lot of crap and it stays in there forever. Drain, refill with distilled.

 

[Firekatt]

Thanks. The overheating issue has been fixed and it is now filled with the proper antifreeze/water mix.