1999 ford f-i50 overheating issues

[x1957x]

I have 5.4 f-150 that started to over heat. Slowly goes up to the hot then creeps back down. The heat goes Up and then down although if I drive it and put in nuetral it will come down faster with revving the engine. Can drive in town all day it seems like, and dont do it. Just when on the highway. It does get warm from the heater but not hot. After awhile that it just blows out cold air. I put a ready remote start in a few years ago and worked great I THOUGHT. But my wife said the heating issues started back then. Never really got real hot after that she thought. Need some good advice guys. Also it does blow the #29 or #19 fuse after awhile to if this is part of the problem or related to the issue. Thanks!

[Scott K]

Is the antifreeze low?

[mwal]

Look in the manual to see what the fuse that blows is for. Have you ever checked or changed the thermostat? Follow upper heater hose normally and it sits on top of engine.it could be stuck shut stopping flow of coolant. They are temperature rated look at manual or service manual for proper one. Any parts store will have them. If it's original it may be working erratically. Just replace and do coolant flush .

[Jeremy airjer W]

Is the antifreeze low?

My first thought as well...

[Eelpout08]

+2

That sounds like the same symptoms I have had with low coolant. Although it should be getting progressively worse if there is a leak. weren't the intake/head gaskets a common problem on the 5.4's?

If the coolant level is ok I would at least try a new thermostat.

[x1957x]

Coolant level is o.k. and I tried a new thermostat. Still the same thing. The fuse I will check today and let you know.

[JOHNBIGDOG]

What color was the coolant? Was it bright green, or mud colored.

[RuKiddingMe]

Is the engine fan electric or belt?

My Durango did the exact same thing - it was belt driven - took the fan off replace the fan clutch and ask was well again.

[x1957x]

it was some what brown but ran a cleaner threw it before draining to. I did put a new clutch fan on it awhile back but it does sound weird when cold, kinda like a real loud jet engine sound or like a diesel with the plenum uncovered. This goes away in about 30 seconds. Never had that sound on the old one. Bought it at O-Rie----lys. This day and age one part fits numerous. Baffles me though. Makes you think if it is even working like it should. Now with that in mind I did take it off thinking I put on a (NEW defective one) and that does the same thing to. I will check the fuse # and see what it runs when I get home at noon. I did find that the (air compressor) 2plug, plug in was broke and did splice a new one in if that has anything to do with it. I also changed the alternator last summer and DID break off the heat senser plugin on the intake by the alternator housing and once again changed that with a new one that fits numerous vehicles to. Dont know if that is a problem though. I do know that if it was trully overheating wouldnt it stay maxed out on the one-who-thinks-I-am-silly gauge. It goes up to just about a 1/4 in. from the h. on the gauge and I rev it up and gradually does come back down for a bit. Thanks again

[x1957x]

still trying to figure this out. (It only blows cold air out of the defrosters with heat up all the way now0. The fuse was the #29 fuse that keeps blowing. Now even putsing around town the gauge goes up and then down more often. If it was truely over heating wouldnt it redline and stay hot and not go right back down in a few seconds?

[Jeremy airjer W]

Is there a control valve inline with the hoses that run to the heater core? Are both hoses hot to the touch? is one hot and one luke warm?

did you burp the cooling system after replacing the thermostat? sounds like there is still air in the system.

The last thing you could do is read live data with a scan tool. IF the coolant temp holds steady around 195-210 degrees while the gauge is moving around than you know its a problem with the gauge. If the temp is swinging wildly than you may have an issue with the sensor.

Worst cause scenerio head gaskets are starting to go bad. Anytime the coolant temp sensor sees air it will not accurately read the temp of the cooling system. It needs to be submerged in coolant. Small air pockets created by bad head gaskets could account for the wild temp swings and no loss of coolant.

[Smoker]

Could be the water pump.