Overheating need help!!

[The_Dealer]

well when i bought my rig, the temp guage didnt work, and i found out it was the water temp sensor, so i replaced it yesterday. when i changed it i forgot to crack the radiator cap, so when i loosened it up i could hear it suck air in. well i bled the system like it says in my ford tech manual(u know the good one), and it seems to have all the air out, but its overheating pretty bad. right now i have straight water in it, the water isnt boiling over or anything and it runs fine. the t-stat is opening up like it is supposed to, but it runs at the N in normal at the top of the guage, and alot of times it creeps up passed the n, when i shut it off and restart after a minuted it goes all the way into the hot, then slowly goes back down. do i need to install a colder tstat in it or do i have bigger problems? so far ive driven it about 15-20 miles in the city so all of the air should be out. no leaks no funny noises, belt is tight, and i have an aluminum explorer 4.0 radiator, so it shouldnt be running that hot

 

[Psychopete]

I would get an aftermarket gauge of some sort to verify that it's actually overheating. Really hard to tell with those stock gauges.

 

[Shran]

First: Psychopete is right, do that.

Second: Plain water is retarded, water boils at 212 degrees! Ethylene Glycol antifreeze boils at 387 degrees... your thermostat opens at 195, do the math!

Third: turning the engine off will NOT cool it down, if it's overheated already and you have no coolant circulation the coolant will just sit there at whatever temperature it's at. So if you got your coolant temp up to say 250 degrees and shut it off, that 250 degree water is just going to keep the engine temp where it's at!

 

[Twister]

I would get an aftermarket gauge of some sort to verify that it's actually overheating. Really hard to tell with those stock gauges.

+1 on an aftermarket gauge. They are cheap and easy to install.

 

[The_Dealer]

well im off to buy some antifreeze and see how that does me, i usually dont run straight water but after trying to purge the system thats all i had

 

[b2rich]

stock gauges suck.
I went to a manual and could really tell the temp. it was still runing hot. i put in a 2" radiator and the temp hasnt gotten over 185 even in 105 degree weather.
im

 

[The_Dealer]

flushed the system and put in antifreeze 50/50 mix, still runnign hot, at freeway speeds its running hotter then at idle

 

[Twister]

you might consider throwing in an explorer radiator. I did in my 85 and haven't had a problem with it running hot ever since.

 

[Psychopete]

still runnign hot

Break one of those hundreds and get a temp gauge. Also check that the front of the a/c condenser or radiator is not stopped up with crap limiting air flow.

Is the radiator new or used? I'd be tempted to feel for cold spots when it's hot enough to be hot, but not burn your hand. But a temp gauge will tell you what the actual temp is, may not even be overheating, but something to be careful about with a 2.9L tho.

 

[H munster]

am i missing something? N on normal is not hot. Its actually on the cold side.

 

[The_Dealer]

my guage starts with n at the top for the hot side, and l at the bottom for cold side...already have explorer radiator

well i finally got it fixed, drained water out, filled with 50/50 mix, drove about 5 miles with the cap on the first notch, and all the air come out, it is now running at the o in normal. also when i got it to operating temp, i stuck a fry grease thermometer in the radiator, and it never got higher then 150, so i guess the guage is a little off as well. thanks guys

now im off to buy a good temp guage lol, is mechanical better then electrical? if i got electric guage could i just tap into my stock sender so i can at least have a backup if one goes out on me?

 

[PaleBlue90]

get a mechanical gauge

 

[adsm08]

And don't tap your stock sensor. I know it's an 85, but the computer still uses some of that info for things. Terrible, horrible, computerized things. A PO did that to my dad's truck when the stock gauge died. Now, no matter what I do, replace sensor, fix wires, etc I cannot get the ECT signal missing code fixed, and the truck only ever gets 10 MPG (granted its a 250 with a 351 and it gets 10 MPG empty or with a car on a flat bed hooked to it, but it's still running rich).

 

[kimcrwbr1]

The 1 wire sender has zero to do with the computer it is for the guage only. The two wire sensor is for the computer the ECT code is either the sensor, wires or computer. If the sensor ohms out good and the wires are good it is the computer try a known good computer and see if it still gives you the same code then it is the coolant temp t-stat or radiator.

 

[marcuspur]

deff get a mecanical gauge to make sure its right in the motor ive had stock gauges say it was hot when it wasnt