I just bought a used 1997 F-150 Lariat Supercab 4 x 4. I get only a small amount of heat.

I have read the other posts on this forum and have a few "Hints" on troublehooting from them.

I was an apprentice Ford mechanics before VietNam but I did not folow up professionaly since returning home. I maintain the family fleet and have always been able to flush the heater and raiator with the kits that Prestone puts out. I flushed the system through the heater core inlet line as instructed. Last night I sealed that hose and attempted to "BACK-FLUSH" the heater core through the outlet line. The water sprayed evrywhere from the fitting and nothing came through.

The truck has 134,000 miles on it and I find the coolant was rusty. I changed the waterpump due to bearing noise. It turned out to be the idler pulley that is fixed to the block near the pump. I changed the thermostat twice and no change.

I noticed that the inlet line has a crimped metal band around it and there is definetly a tubular object inside the hose.

My guess is this is a flow check valve and it possibly is rusted in a closed or nearly closed position.

I have had f-150's up to 1995 and have not experienced anything in the hoses. This waqs a model year change and could be an attempt to block an air pocket if the coolant is allowed to go low in the expansion tank.

Can anyone verify my insanity on this?

 

i have heard of some of the ford trucks that have a restrictor plate/ tube as you said. i think it slows the flow down and causes a reduction in "noise" thru the heater and hoses. i would pull it out and see if you get flow--- if its plugged, throw it out.

 

You are right it has a restrictor. I cut the hose and found it in the hose with junk plugging it. The previous owner did not keep up with coolant changes.

I plan to replace the hose with a splice made of 1/2" copper waterpipe. I can gain access to the heater core for flushing it in the future. I don't think I'm through living with the problem as yet.

Thanks for the information.

John Johnson

1997 F-150 Lariat Supercab 4 x 4 134,000 miles
1984 Ranger, ex-Air Force truck, salvaged at 40,000 miles - retrofitted with 5 speed, yet to get slave cylinder working.

 

I think it's Prestone that makes a flush kit to install vs the copper tee. It's basicly the same thing, except made to work with a garden hose.

Mike