winall941

someone please help me out....i have a 2001 f150 4.2l v6...a couple weeks ago i was headed to the beach on a hot day. I had the a/c turned on high and my truck overheated. I stopped turned the heat on high and let it cool down. i finally got to the beach after it did this one more time. The nxt day it was cool and i had the a/c on high and never did it. On the way home it was like 93 degrees and i rode with the heat all the way home so it wouldnt overheat. The second i turned the heat off it did it. A couple days ago i put a new thermostat , water pump, belt, flushed the radiator and the block and everything was fine. Today i drove to work and back and while backing up my drive way the hose on top of the radiator blew off and all the fluid blew out. I filled it back up, put a new clamp on and started it. Turned the a/c on high and the gauge goes to the red, comes down and goes back up and overheats. This takes about 10 minutes at an idol. I have not the slightest clue as to what it could be. Please let me no if u have any suggestions or thoughts.

THANKS

Good old Bill

Hi fella, I have an 02 with the same 4.2 and have a couple questions. How many miles? Have you used a coolant mixture of 50/50? Ratio of water to antifreeze. Does your system have a separate fill tank or is cap in the radiator? Last summer I did preventative maintenance on mine. Hoses, belts and t-stat. It was very hard to get the system full of mixture so my gauge constantly went cool to high, had to have heater on during this fill period. Two suggestions. Make sure the system is full. Second, with the A/C on and overheating is giving me a bad feeling as to the efficiency of the radiator. If a radiator shop is available, ask them to check for efficiency. I'm fearing not enough antifreeze was kept in the mixture causing corrosion and thus plugging the radiator.

captaincamf150

ya know man i have a 2001 super crew with the 5.4 , and i have the same problem, now.... what i did was put some electric fans on the front to help pull cold air into the radiator . but i am wondering if i have corrosion in it like the other guy was saying.....dont feel like buying a new one!! but let me know if you figure something out, but the fans helped me some, so u might could try that...

winall941

hey i have 84000 miles using a 50/50 mixture and i have a separate fill tank. Its so confusing because it only does it on hot days. Idk i might try a new radiator or pull on from a newer one to see how that works. Thanks for all the help guys il let u no what happens.

Mtrautsch97

I have a 97 4.2L that is showing real similar problems, however, I see mine overheating when I get up to 70mph range. I can drive around all day 45-55mph but when I hit interstate speeds the needle raises immediatly. Would this be a radiator? Any ideas?
Thanks, Matt

captaincamf150

from what i have heard in the past our motors like running a little hot...which sucks. some one said something to me at one point about some type of coil in the engine that causes over heating??? anyone heard of this...not sure what it means , or if its true, but if it is how do you fix this????

Good old Bill

Mtrautsch97, Yes pull the radiator and get it fixed or replaced. Theory about cooling systems that no-body wants to believe. T-stats control MINIMUM engine temp! Can they stick shut and cause an engine to overheat, of course. Would love to have a dime for every t-stat changed that didn't fix a blasted thing, except help the economy. Radiator cooling efficiency controls MAXIMUM engine temp! High speeds, means alot of ram air doing the heat transfer. Slow speeds, the fan clutch or electric fan kicks in and pulls extra air to do the same heat transfer. Now other factors or symptoms. Start engine, overheats immediately, no coolant flowing, t-stat. OH highway and city driving, radiator. OH highway only, radiator. OH city driving only, fan clutch or electric fan. Hope this helps.

NGM

The 4.2 is bad about cracking heads and blowing headgaskets. Might want to look into that. Changing all the stuff you changed might have fixed the inital overheat problem, but the damage would have already been done. The key is the top hose blowing off. There is combustion gases getting into the cooling system would be my guess. There is a simple test for it. There is a tester that you should be able to buy at Napa. IT has a vile that you put a blue liquid in (comes with the kit) and stick it on the pressure cap opening. If the fluid turns yellowish then its picking up combustion gases in the cooling system. Good luck

Good old Bill

NGM the tester is call Block Check. Have one and it works quit well. Does NAPA sell it as a home owner one time thing, because it was not that cheap to purchase?

winall941

thanks again everyone,...Tons of help