About half a year ago my heater core blew up. Fluid everywhere. The truck 98 F150 off road 4x4 4.6. Was still under warranty, now it isn't. But now the heater works barely. During an idle you can not feal any heat coming from the vents. Driving about 70 then a tiny bit of heat will come out. Could a faulty heater core have been put in? Winter is coming and i havent a clue lol. Any assistance would be appreciated.

 

Check your coolant level first.
If it is ok,then you may need to flush out the heater core.
Jimmy

 

How many miles are on it? My 4.6 did the same thing with heat only at certain speeds, turned out the metal heater "pipe" that runs under the intake had rusted out and was spilling coolant all over the top of the block. Thankfully I caught it in the early stages so the hole was fairly small but significant enough to keep me cold on the way to work.

It's odd how I spotted the coolant leak though, when I first got the truck I shot all exposed areas of the frame in Rustoleum Semigloss black spray paint. When the heater stopped working, I popped the hood and noticed all my paint look like it had been eaten off with acid, but only on the right side frame rail. Followed the leak to the pipe. No telling what all I would've had replaced first.

 

The trucks has 66000 miles. 98 4.6 auto. i looked in the engine cavity and i did not see anything unusual. Besides rust on spot i don't want And the fluid level is fine. I will try the flushing this weekend lack of time. Thanks for the info guys. We'll see hopefully

 

Is the heater valve opening properly?

 

Where exactly is the heater valve? are you talking about the valve with the ***??

 

OK, I did a little homework since my last post. I thought the f150 had an old-fashioned valve that controlled the degree of waterflow through the heater core. It doesn't. Instead, hot water flows unimpeded through the heater core 24/7/365. The degree of heat emitted into the passenger compartment is regulated by a blend door in front of the core. The degree that the door is opened (which is controlled by the position of the center **** on the hvac panel) determines the amount of heat emitted into the passenger compartment.

Essentially your problem can be caused by any of the following:

1. Low coolant level.
- Obviously check the overflow tank to ensure the proper level of coolant.

2. Partially or fully blocked heater core.
- To (CAREFULLY) check, run the engine to operating temperature and very carefully determine the temperature of the inlet and outlet tubes of the core. These tubes are located in the firewall (where the heater hoses run into the firewall) Both tubes should be very hot. If either or both are cool or lukewarm, then you have a blocked heater core, or a blockage before the core. If both are very hot, the core is probably all right.

3. The blend door is physically stuck or binding.


4. The actuator (center **** - electronic device) that controls the door is bad.

 

ok. great ill do that check asap, thanks

 

Ok, i went out and ran it for about 20 minutes and felt the lines with heater going and not going and only one line the top line was getting hot. the other cold. So this is a good indication that my heater core is bad?? Thanks for the help gents

 

Possibly just clogged or it has an air pocket in it. I would remove the lines(afetr draining the radiator) and use a garden hose to try to flush it out. Put the garden hose into the side that is cold.
Jimmy

 

Does the temperature gauge get up to the normal range?

 

Yes the temp gauge reads good. :S

 

Alright, I flushed the system out today. i hooked the garden hose to the lines going into the heater core aswell both inlet and outlet and was pretty clean. After putting it all together and such start it up and the heater hasn't any heat now. Now i realize that changing the core is a pain in the butt. But the actuator or heater valve may it be called is that an easy part to change? The temperature is normal or about 3/8's on the gauge. So im guessing the thermostat is good. Other then those components i do not know anything else of the cooling sys.. Your guys help is appreciated. thanks.

 

Also i forgot to mention. When i went to defrost i heard kind of a ticking sound it was faint coming from the engine compartment. When i turn defrost off it went away.. It that helps with troublshooting i don't know..

 

Watch for a broken heat control ****. It may have a small crack that wont turn the shaft of heat control switch. I would pull the **** and use something to turn the shaft to the hot position carefuly. Let us know. good luck frosty