1994 F-150 Pickup overheating
 

My husband is having problems the last 3 yrs with overheating he replaced the radiator, water pump 2 yrs in a row and the last one last yr had no fins on it anymore. now it is starting to over heat again this year. We were told that the ford engine sometimes rust from the inside out does anyone know if that is true and if they have any ideas for us he flushed the cooling system different times and the water is a rust color changed themostat and all he doesn't know what to do any more he is ready to get rid of it. I only has about 146,000 miles on the motor and it is a straight 6 the 4.9. Help someone if you know anything about this:confused:

Has it ever had a leak in the cooling system? Many people will dump stop-leak in a radiator and never think about it after the leak stops. If so, the stop-leak may have caused a blockage somewhere. Take the truck for a flush. Not just a drain and refill. Some shops have equipment that flushes the whole system while the vehicle is running. That's is what I would look at first.

The key to the issue I think is that yer friend has a major case of electrolysis going on. That can cause the impeller on the water pump to be eaten up and it can destroy a radiator fairly quick. Hopefully, he hasn't dumped some of the radiator additives like Water Wetter in it. If he did, sell the truck as there's no fixing it. Here's a linky on how to test for electrolysis.
http://www.rondavisradiators.com/tech.htm

Has he by chance replaced the heater core?

What Labnerd said plus you said the WATER came out rust colored. I hope you ment coolant because if you are using straight water that would be the root of your problem.

How do you know it's overheating? The gauge isn't extremely accurate, so if that's the only indication, it could be just a fault in the sender, gauge, or wiring. Read this caption:

https://www.supermotors.net/getfile/...tempsender.jpg

If it's venting hot coolant (steam/smoke), that's a sign of a leak - not necessarily overheating. It could be a bad cap.

If it's losing coolant from the reservoir over a period of days, it could be a leak in the overflow hose or tank.

If it's running warm, that's not the same as "overheating". Get something like this:

http://www.northerntool.com/images/p.../715503_lg.gif

For more info, read this:
http://www.fourdoorbronco.com/board/...ead.php?t=5230