i have a 86 f150
i have replaced the thermostat and housing, checked heater core( not plugged up or damaged)

when i first replaced the thermostat, it ran good, and the last couple of days it will shot out antifreeze from the hole on the overfill jug on thee driver side but the guage only shows on the M or A ( thats where the needle is pointing to before i shut if off.
could i have just bought a bad thermostat or am i looking at a head gasket or water pump?

i have turned the truck on with the raditor cap off and the water does move back and forth so i assumed that the water pump is working properly.
i also noticed that the raditor has a lot of metal tabs from the raditor laying underneath the raditor .



there is no water in the oil and i have no oil leak. i have the same amt of oil and i havent lost any pressure.

if u could shed some light on this , i would greatly apprecaite at.

 

Did you install the thermostat backwards?

Factory gauges are unreliable, I'd want to verify with a 3rd-party gauge.

What made you decide to replace to begin with? When did this problem start?

 

the truck was over heating before i changed it. and when i changed it didnt over heat till now and now it overheats before the guage shows hot.

no i put the thermostat in the way autozone told me and the way the old one was in there.

so doe sit sound like its a head gasket or a water pump maybe or just a faulty thermostat?

 

The truck was already overheating and replacing the thermostat didn't change that behavior
(I'm assuming you replaced it to try and alleviate those symptoms) so I really doubt the
thermostat is the cause.

Having the needle at the A and R on your temp gauge seems a bit high to me BUT there
are known problems with factory gauges. First thing I'd do is verify everything using a 3rd
party gauge with actual numbers on it.

 

what could be the cause of the problem

 

There could be several, it's real hard to tell over the Internet. Again, my first approach would
be to verify the existence of a problem and have some hard numbers to work with.

 

is there any way i can test and see if the radiator , water pump and head gasket and thermostat arent bad?

 

The only way to test these things...

Take the Thermostat out and boil it in a pan of water. It should open up. If it doesn't it's defective.

The Water Pump or radiator, you can start the truck with the cap off and rev the engine. It should suck the water level down if it's free and open and pumping water. After a moment it will spit the excess water out the radiator opening when the water returns from the engine. (Do not do this for too long, otherwise you can damage the engine from running out of coolant.)

This autozone thermostat has me thinking. Did the truck run cool for a time after replacing it, then the symptoms came back? How are the radiator hoses? Are they really soft? or are they hard Cracked? I've seen the bottom and top radiator hoses suck closed before when they get old. Really easily squished together etc...

 

i did take off the radiator cap. when i hit the gas, the water sucked down ( it was running out of the fill hole until i hit the gas), then afterwards it did start to spit the water out.
like i said earlier there wasnt water in my oil. the thermostat i replaced about a week ago. b4 i changed it , i saw the temp gaugse, climb and keep climbing until i turned the truck off b4 it over heated. this time it is overheating before my guage showed hot. im pretty sure my guage is working right because the last time it over heated it was by the H.


when i took off the old thermostat, should i have seen anitfreeze sitting there in the head gasket?

when the truck got hot, i noticed the top hose was hard as a rock.

 

Did you replace with new fluid and proper mixture? To check the thermostat, I beleive you start the engine get it hot, the top hose should be cool, when the thermo opens it will turn very very hot. I even here mine click open if I really pay attention, like right after I install it
Hose being hard when you got it could be a coil thats inside of it to keep its shape.

 

I had an 81' with the same set up that did the same thing. It ended up being a partually plugged radiator. Visual checks told me that the coolant was moving through it fine, but after replacing the water pump didn't remedy the problem I pulled the radiator and brought it into a shop to be flow tested. That was the eureka moment. Since it was only partually plugged it was allowing the coolant to flow, but not enough to keep everything cool. I say follow what ctbutis suggested and put a temp gun on the block to verify your gauges are reading correctly. If it IS overheating remove the radiator and have it flowed. There easy to r&i and while you're at it replaced the upper and lower hoses too. Another thing that bothers me is that your finding missing peices of the radiator fins on the core support. That tells me either the radiator is plugged or something got shoved in it possibly damaging it. Pull any other coolers away from the radiator (ie. a/c or trans) and make sure it's free and clear before extraction.

 

i flushed the coolant system out myself, bought the flush and fill kit and used the cleaner and flusher that was recommended. i noticed the drain plug hole was plugged up but after about 15 min of running water through it(radiator), it cleared it out. but after i flushed the system, i took it down the road , about 5 miles and came back and when i stopped at wal-mart, it over heated AGAIN( when i say that, the guage didnt show hot , it showed the guage going up though, 5 mins after that it wasnt hot at all). this time there was antfreeze seeping from the thermo housing top radtor hose area and heater core inlet tube where it meets the heater core. ( the day before i took out the heater core to see if it was plugged, so i think it wasnt tighened down. i retighned all hoses and apparntely when i thought i lost a lot of atifreeze on the ground i didnt lose that much because the next day , when i checked it, the raditor was full so i dont know if i created a air bubble in the system and thats what cause it to blow out antifreeze.

when i flushed the radiator out i only un did the top hose not the bottom one.

 

Well Topaz overheated in the same fashion after I flushed my radiator. Took it to Midas after hours of fighting with it, there was an air bubble in the system.
Same thing could have happened with you, as for blowing out antifreeze, that could be a possible side effect of an air bubble.

 

Yeah those air pockets in the system sometimes take a while to get out especially when you really flush and drain the entire system.

 

That they do. It really helps to squeeze the upper and lower radiator hoses with the cap off after flushing and mostly filling the system. It is amazing at just how much air will come out, especially from the top hose. Once the air seems to be all out, the system can then be filled to within an inch or so of the cap. A little air in the radiator will usually stay there and not circulate through the cooling system.

Did the OP test his radiator cap? It should hold a fixed amount of pressure if it is a good cap. Coolant will boil a lot more easily at 0-3 psi than it will at 7-15 psi. Different years / engines use different amounts of coolant system pressure but a Hayes or Chilton manual will show what is appropriate for that particular vehicle.