I have a 2000 ford f150 5.4 and I just started having problems with it overheating, under normal driving conditions it runs at
normal temp. My edge shows around 200 degreese, but now if you drive it hard or tow a trailer as small as a single axle utility trailer it over heats.. It got up to 246 and the oil temp light came on and I had to pull over for a bit.. All the fluids are good, not loosing any coolant and no missfiring... Recently had to replace the intake manifold cause it cracked at the water crossover, new intake gaskets, thermostat, plugs and coolant... Any help would be great.. Thanks

 

uhm possible bad thermostat..... granite its new but it could be faulty... how long ago was it replaced?

 

I did the job probably three months ago or so. I thought the same thing so I put the old one back in and still doing it? I guess I could try another new one?

 

yeah try that.. if not that try flushing out ur whole system... if it warm where u live flush it fill it with water run it for a bit with water and drain it back out and put coolant back in..

 

Yeah it's in the upper 90s every day in the summer here.. I'll try that! Thanks

 

yeah i think they make sumthing that u add to do a flush.. u may just have some stuff in some lines... but yeah run in with water in it with the flush stuff in it. i forgot what brand i`ve used before.....

 

Make sure your radiator isn't clogged up. I'd recommend a new pressure cap as well. I had some overheating issues with mine back in January, thought it was head gaskets or the tstat. Ended up just being the pressure cap on the coolant reservoir.

 

had the same problem wtih my truck, try the thermostat, there cheap....

 

Depending on miles the motor has on it, it could be a few things.
Did you flush the system when you added new coolant?
Some people run the same coolant up until the engine seizes due to being filled with rust and clogs. It needs to be changed, (miles per change & or life of coolant is listed on the anti-freeze container, I believe), but is in the owner's manual. If don;t have one you can pull it up on line.

I bought & added the flush kit to my trucks to allow flushing each time I change coolant, (it mounts on your heater hose). You can buy them at any auto parts store. Simplifies flushing.

You may want to use the Super Flush from Prestone to do a good flushing. Flush comsumes a bit of time but is worth it. Time consuming is waiting for engine to cool down, but great time for a cold beer!!

Also is your belt good & or water pump?

 

She has 149k on her.. Been a great truck! I changed the fluid when I did the intake manifold but I didn't flush it with any kind of flush and then put all new fluid in it.. Yeah the belt is in good shape and as far as the water pump I'd say it's good? But you can't tell just by lookin at it? Lol... Someone did tell me it might be going bad though so it's not pumping enough under load? But I'm not sure? They also said my transmission but I'm almost positive it's not the transmission running hot.. I think I'm gonna start with a flush and go from their?