Hey all, I have some problems with my beloved truck. Hope you can help.

First I had a leak around the water pump, so I had it replaced. Now I am having overheating problems.

The temp is fine when I first start up. After it warms up it starts to overheat. When at a red light the truck over heats when I take off it cools down somewhat. When I am in park the truck overheats when I bring the rpms up it cools down. When I let off the gas it heats back up. I have already replace the clutch fan, and it is make no difference.. I do not want to throw away more money. Hoping you all can help me narrow down my search. What should I look into next? Please help. I will be pulling a 5th wheel in less than two weeks. Need my truck to work.

 

What engine? You guys have to give more info if you expect help.
Craig

 

sounds like a bad t-stat

 

Agree with previous post. What brand T-stat? Stant = Junk. Motorcraft or NAPA is all that I would recommend and install. Also, if radiator cap is old or Stant, purchase a $12 Motorcraft radiator cap. Faulty, defective, old radiator caps produce same overheating issue as well. Air in coolant system. Abused cooling system plugging passages in block and/or heads.

Edit: I re-read earlier OPs post concerning, "so I had it replaced." If you didn't do the work yourself, then 99.9% that local mechanic (if it wasn't Ford dealership) installed cheap t-stat. Went thru this last year on wife's cousin dodge. I She called me complaining that the car would barely put heat out after 30 mins of driving. Pulled t-stat housing, junk Stant t-stant installed by "Reputable" mechanic here, in business for 15 years. Reason why..$8 vs. $30 Dodge t-stat. He said that never happens when he does this sort of repair...

 

Did the overheating just start after having the water pump replaced?

Do you still have the fan shroud behind the radiator?

 

Nice guessing. But without knowing what engine it is hard to give any facts. EXAMPLE: if it is a 460 & the water backing plate was left off the issues he is having is exactly what happens if a backing plate is missing? How I know is I had a pump installed & had the exact issue he is having. After chasing the T-state, fan clutch I got to looking to find the idiot shop didn't install the water pump backing plate.
Second a 460 needs an OEM fan clutch to work proper.
SO WHAT ENGINE IS IT????????????????????????????????????????????
Craig

 

Either this or you have a huge air bubble behind the t-stat. If this all appears good check the fan clutch depending on how long it takes to overheat and if it happens drioving or idling.