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

 

[ForOffRoadDriving]

put some antifreeze in it, you dont want to run straight water for too long because it can cause rust build up (iron in the water) and also its not as effective as a cooler as antifreeze increases the boiling temperature. is your fan clutch still operating properly?

 

[The_Dealer]

fan clutch is working properly

 

[swamprat]

Have you flushed the system? Is a hose collapsing? Rad clogged

 

[The_Dealer]

system is clean, flushed it not too long ago, but my guage wasnt working so i dont know how long its been running hot, or if it really is, radiator is about 6 months old and isnt clogged, and the hoses arent collapsing

 

[swamprat]

I put a cheap set of guages on my BII. Temp, oil alt. I had a 4.0 with 4.0 rad and it ran around 190 temp. I could go inside for 10-15 min and start it up and it reads around 220. With in a few miles it is at 190. Sounds like yours is doing something similar. That is normal. The main reason of putting the guages is for the oil pressure guage. Ford is known for unreliable guages.

 

[robertc1024]

I had an overheating prob, pulled the rad and it was so full of crud, you couldn't see through it. Power washed it, No more probs. You might check that.

 

[Hotrodlincoln]

Sounds like heat soak to me, which is pretty normal. When the truck is off the excess heat from the block (which is cast iron on the 2.8) makes the coolant that's still in the block hotter because there is no flow to dissipate the heat. When the truck is restarted a few minutes later the hot coolant is pushed out and replaced by cool coolant from the radiator. This drives the temp needle up as the hot coolant flows past the temp sender. Once the higher temp coolant is pushed out into the radiator and the now normal temp coolant beings to flow past the sender, the needle comes back down.

You should drain that water out and get a 50/50 mix of antifreeze in there.

 

[spdcrazy]

mine usually reads 190 to 195. then when i turn it off and get back to start it up a few min later is always reads 220ish. just like swamprat says. good ol ford!

i'd look into a cheapy water temp gauge. i always preferred numbers over guessing how cool it is on the N or how hot it is on the L

 

[kimcrwbr1]

That is normal for the 2.8 with the Tstat on the lower hose. As long as it stays in the norm range you are ok. When I did my duraspark I found a Tstat housing for the upper hose off the intake manifold from a 85 B-2 with a/c. I pulled the stat out of the lower housing and put it in the upper housing. The old bypass went from 1" to 3/4" on the intake I just plugged the 3/4 nipple and ran a 1" to 1" up to the new housing. I got lucky and found it when I was looking for a carb spacer but cannot find it in any parts outlet. It is a 2 piece housing and the engine temp stays alot more even with a 195 stat the guage never goes above half on the guage. To bleed the air out on the system the best way I found was to put a flush attachment on the heater hose coming from the core and just add water slow there as the engine is running. the air lock gets in the heater core and the coolant dont circulate proper with air in there. If the heater is working good then the bubble is gone.

 

[The_Dealer]

mine is an 85 with the upper t-stat, at highway speeds its showing it runs hotter then at idle, which doesnt make too much sense to me

 

[shane96ranger]

put some antifreeze in it, you dont want to run straight water for too long because it can cause rust build up (iron in the water) and also its not as effective as a cooler as antifreeze increases the boiling temperature. is your fan clutch still operating properly?

I agree, put a 50/50 mix in it.

 

[kimcrwbr1]

Before you put any antifreeze in it backflush the radiator good. Disconnect both hoses from the radiator and stick the hose in the fill on the top. It works best with a long hose but kink the hose with no nozzle on the end and let it build up pressure and hold your hand over the lower hose and release the pressure do that a bunch of times. Hopefully you can force some of the crud back out the other side. If you pull the radiator you can stand it on its side so the stuff runs out also. It does sound like a radiator issue but I would change the stat too. Sometimes if the radiator is partially plugged you can feel cool spots on the core where the coolant isnt running thru it. also you can pour bleach in the radiator 50/50 with water and let it sit overnite then flush it good both ways. Easy off oven cleaner will also dissolve the crud in a heater core and radiator without damaging it. If it leaks it was bad anyway.

 

[odie1969]

If you pull the radi. most radi shops will test it for free. if it has any restrictions of flow your highway temps will increase.

 

[kimcrwbr1]

Does your fuel guage also go higher when your at cruising speed or do the headlighs flare when you give it gas that could also be a charging system issue. Just something to look at hope you get it figured out.