Brandon Salisbury

Hello everyone. I have a 2003 4.6 supercrew that is have started recently having a issue with over heating. I live in south Texas and it's been hotter than hell this summer. Anyway, about 3 weeks ago, I was on my way home and about 15 mins into my ride, it over heated. I pulled over immediately and popped the hood and the coolant boiling. I got back inside the truck and started it and it was fine. It has gotten worse now but as soon as it over heats now, it boils over. As soon as I shut the truck down and restart it, everything is fine. Any help would be appreciated. A few quick things. I am putting coolant in it about half gallon a week, the AC is running when it over heats, there is no sign of coolant in my oil and cylinders 2 and of course 4(like most) are showing a misfire. Thanks!

GhostriderI

How many miles on the engine?
Has the:
thermostat ever been changed?
Cooling system flushed?
Engine had coils and plugs checked?

Just throwing things out.
Hope these help

Also could have an air bubble in the block trying to work its was out.

Brandon Salisbury

130,XXX none of that yet...I know that I need to do the coils and plugs but would the thermostat cause the overheating issues? Also, when I open the reservoir for the coolant, it's sucking air. Even if the truck has been sitting all day at work, is that usual?

joshparrish1992

I mean without having a good look at whats happening it can be difficult to figure something out like that. I would check for the obvious things like if your radiator and radiator fan are in good condition (as in not packed full of dirt). And if you are adding that much coolant in it sound like you have a leak. So trow a big piece of cardboard under you truck over night and see if you can find where all of your coolant is going. Other than that I would take it to mechanic to try to figure out what is wrong.

Brandon Salisbury

Ok, well, coils and plugs and new thermostat are happening next weekend...hopefully it will hold up for that long..lol...I will get a box under it tomorrow and see what happens from there...I'll keep y'all posted

GhostriderI

Thermostat maintains a steady temp in the engine if it cycles open to late/sticks closed the engine temp will be higher/overheat, as far as sucking air mine does a little, as just enough to hear it, is the reservoir full to the full cold line with coolant after sitting at work? If not, for the next few days, top it off the that point every day before you go home and if there is time check it before bed and do the same so you don't have to do it before you pull out before work until it checks good.

josh has a good idea also

Brandon Salisbury

When I say sucking air, I mean, as soon as you turn the cap, it starts and if you open it to fast, it sprays out ...never seen it before...

GhostriderI

Are you sure it is sucking (has a vacuum) not blowing (has pressure)?

Brandon Salisbury

Blowing I would guess

GhostriderI

ok the closest I have to match you is my 2006 Crown Vic. when cold I get a small vacuum in when warm I get a large pressure relief (15 psi). something to try, next time it shows hot don't open the cap but do everything else you do and see if it resets as you describe to normal operation (thinking the temp sensor could be bad and reading low until way over temp then spikes when you shut down and restart it resets to the bad setting) Do you have gauges or lights for engine temp?