1998 Ford F-150 Heater not warm enough!

Tiny
GREYHAIR
  • MEMBER
  • 1998 FORD F-150
  • V8
  • 2WD
  • AUTOMATIC
  • 277,600 MILES
I've had this vehicle since it was new. About 2 years ago I had to remove hoses from heater at firewall and blow the rust out of the heater core to get it to heat like normal in the cold weather. That fixed the heater problem at the time. When it got cold this time, I did the same thing and a large amount of rust came out so I thought the problem was fixed. I run almost 100% pure antifreeze and always have. There are no leaks in the cooling system and the temp gauge is not indicating lower or higher than normal operating temp, but even when the engine is sufficiently warm, the air coming through the heater is simply not very warm. If the fan is run on any speed other than low, the air actually becomes cool. It doesn't appear that there is sufficient coolant flowing through the upper radiator hose, but the overflow tank is at normal. I've replaced the thermo thinking it was stuck open, but no change. Is there something about the cooling system on this vehicle that is peculiar about clogging with rust and restricting coolant flow through the heater core? Help?
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Saturday, January 17th, 2009 AT 10:27 AM

5 Replies

Tiny
BLACKOP555
  • EXPERT
Is the antifreeze compatable with your type of system?

Have you ever flushed out the entire system. Radiator, hoses, block. Everything?

After you flush out the entire system check the current in the radiator, use a electrical tester and check the electric rate in the radiator.

If it is higher then specifications you will have to use aditional grounding straps on your cooling system.
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Sunday, February 15th, 2009 AT 9:04 AM
Tiny
GREYHAIR
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I have used Peak antifreeze since the first time I changed it out in the vehicle about 2 years after I bought the truck and I used it again this time. I am assuming it is compatible since I"ve never had a problem with it before. Had a similar heating problem in a Suburban in the past and discovered the problem then with current. Replacing it with Dexcool fixed the problem in that vehicle.

I flushed the entire system about 2 years ago (probably had done it a couple of times before also). Also replaced the radiator at that time, along with water pump.

Never have checked the current in this system. Would that keep other components in this system from working properly? Do you mean grounding straps attached to radiator, other metal parts of the cooling system, etc?

Someone else mentioned that this vehicle might have some kind of flow restricting device in the cooling system and if it is not present it could cause this problem, but I can't find anything about that in the actual Ford repair manual (two volumes) that I have for this truck. Do you know of any such device in this system?

Thanks for your reply. The help/suggestions are greatly appreciated.
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Wednesday, February 18th, 2009 AT 12:39 PM
Tiny
BLACKOP555
  • EXPERT
If yoiu got the current it can cause electoalaysis in the system and eat up the componenets fast, adding more ground straps would cause the current to leave the radiator faster.

The flow restrictor can be used in cases like yours to attempt to stop it, if that dont work you can put in copper/brass pieces in the hose and solder ground straps on them and then attatch the the frame.
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Sunday, February 22nd, 2009 AT 6:53 PM
Tiny
GREYHAIR
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Thanks for the replies. I will check into the electrical current situation. I appreciate your help!
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Tuesday, February 24th, 2009 AT 9:26 AM
Tiny
BLACKOP555
  • EXPERT
Just if the electrical current is within specs, then you should be good to go without the extra grounding pieces, and you should be looking at a flow restricter.

If the current is high add those grounding pieces.

I am here to help. Thanks for the donation.
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Tuesday, February 24th, 2009 AT 9:44 PM

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