Hello Everyone,

I was hoping to get some advice on an overheating problem I am having. I have a 98 f150 V-8 4.6 Liter. When I am driving down the road my temp guage is right at the H level. This usually happens when I am going up a steep hill. I can't pull my 13'x5' trailer without it overheating.

I replaced the heater core a few years back, the radiator twice, and put new thermostates in.

I am currently not getting any leaks frrom anywhere. The oil level is fine. The other thing is my heat doesn't work. The switch is fine, the hot fluid i traveling to the heater core but no heat comes out of the vents.

Could the no heat issue be related to the overheating problem? I'm not sure it's really overheating either. Could the guage be messed up?

Cliff

 

Yes, the gauge could be messed up, but that wouldn't stop your heat. We presume "right at the H level" means its running hotter than before. Perhaps the water pump is no longer up to the task? Has it run on water only often & had rust/corrosion in the old radiators? Also sounds like the dreaded head gasket leak fizzing until a bubble fills the heater core & leaves water level low in the block, also linked to limited antifreeze protection. Look for white smoke (steam) out the exhaust at start up & sniff for exhaust/gas smell in coolant.

 

Is the water circulating through the radiator? Waterpump? What about the temp. sending unit itself, did/have you changed it? When was the last time you changed the thermostat?? Feel the top hose (at Op. temp.) is it hot? Just some suggetions.

 

I'd start with the temp. sender and go from there.

 

Hey Guys,

I appreciate all of the responces. Responce to Club Wagon:

I s there a test I can have completed to see if the water pump has gone bad? Also, I don't believe I am having a head gasket leak as of yet. I am not getting any of the simptumes you talked about. Also I am not losing any radiator fluid. I would assume if I am leaking from the head gasket my fluid would slowly dissipate, depending on the severity of the leak.

Responce to Moore FOMOCO:

The radiator and thermostat was replaced less than a year ago. My original thought was the fluid wasn't being sent to the radiator. I checked the thermostat and it is working properly. The top hose does have HOT fluid in it so I am assuming that the heated fluid is being sent to the radiator. Could there be something wrong with the radiator internally?

Respone to Galaxie641:

Is the Temp sender the same as the Heat Sensor? My buddy thought that maybe I had a bad heat sensor. I'm not too keen on actual parts and what their complete job is.

 

Sounds like the beginning of a head gasket leak. Crank it up with the engine cold and see if the top hose builds up pressure before it gets hot.
Running without a shroud will also make it run hot.
As for the no heat from the vents, make sure your blend door actuator is opening the blend door. If you're getting cool air out the vents but not hot that's the first place to look (after stripped out *****).

 

Remove the oil cap (valve cover) and look under it? Any milky looking stuff..Pull the oil dip stick... head gasket.
Remember water in oil (pan)=head gasket; oil in water (radiator)=cracked block.

 

When you say it's overheating, are you going by the gauge or are you actually seeing steam or some other indication that it's overheating?

A couple of easy checks to try.
re. no heat, the temp adjust ***** on these older F series are known to crack where they fit over the control shaft causing them to free spin as opposed to actually turning the temp control. To easily discount this you can take the **** off of the fan control and swap it with the temp control. My 98 wouldn't heat either until I did this swap and it's been working fine since.

re. gauge showing overheating, if your only going by the gauge and you don't see any other indication of overheating, it could either be the sender or a loose elec connection at the sender. I don't know if the sender increase resistance along with an increase in heat or if it decreases resistance. You could disconnect the sender and see if the guage pegs out to max hot or stays max cold.

If you've tried these easy checks and still have overheating/no heat problems then the next thing you'll want to do is to verify that you've got coolant flow through the radiator once the engine warms up then go from there.
Good luck

 

has the fan clutch been replaced?

Mark