I have acquired an 89 Bronco 351W that I can't seem to keep from overheating. I drove the bronco 200 miles home after buying it and it never overheated while cruising at 60 mph or so. Now I can't drive 10 miles without it overheating and spewing water/anti-freeze out the reserve. I have so far, changed the thermostat, radiator cap, upper and lower radiator hoses, and did the generic at-home flush, and parked on an incline to hopefully keep air pockets out of the system. The fan doesn't budge and the water pump doesn't leak so I'm assuming the water pump is fine. The fan spins about half way around when I spin it so I'm thinking the fan clutch is ok.(just things I've read about with other threads). It runs strong when it's first started but once it starts getting warm it begins to really dog out and sometimes requires full throttle to get up a small hill. FYI: I have put out a thread asking about an exhaust leak in the tube that leads to the EGR valve, and a wire that goes nowhere (orangebrownish that's in the same bundle with the green egr wire and red/black wires that go to a canister), and also I have a pretty good oil pan gasket leak that's giving me fits, or basically I don't have the $450 to get it fixed as of yet. Thanks again for everything.

 

Remenber just because the pump dose not leak dose not make it good. The impeller may be wore out and it may not be pumping water. Also with it doging out when warm, the timing may be off, that will make it heat up also. Just some things more to think about. The clutch fan may not be engaging also.

 

Warm it up and observe the radiator for flow with the cap off. Make sure the t-stat is installed correctly, a major cause of issues and easily done incorrectly. As posted the impeller may be defective. It sounds like it could also be an EGR issue or a converter blocked which would overheat the engine and cause performance loss.

 

That doesn't sound right to me. What were the conditions that you tested this under?

At 60 MPH, you don't need a fan. Plenty of air getting shoved through the radiator. At lower speed, and stop and go, you do.

 

Ok here goes, haha I had the timing checked and they said it was set on 10 which is supposedly where it's supposed to be. As for the Cat Conv, for some unknown reason it doesn't have one. The tube leading up to the EGR is definitely spewing major exhaust, and when I take off the radiator cap the only flow is pretty green fluid flowing out the top of the radiator once it's warmed up. One thing that grabs my attention is the amount of mud and dust that I've cleaned off and out of this thing. Should I just take the radiator out and have it completely flushed and cleaned? Oh and BTW, just for your helpful advice I'm going to turn my longhorns right side up in the gameroom for just one day..haha Boomer Sooner! thanks again for everything, and I'll keep on trying.

 

I just read somewhere to try and spin the fan and if it would spin more than a full turn there was probably an issue with the clutch. Is there a way to test out the fan clutch? It's like being between a rock and a hard place, it will run well when it's cool, but once it get's warmed up you have to floor it to make it up a small hill which in turn makes it get hotter. I mentioned I changed both radiator hoses, but I failed to mention that both times they just exploded due to the pressure. I'm trying not to give up on this thing. (especially since I talked my fiancee into letting me buy it off of ebay) Just trying not to look like a dummy..haha Thanks again.

 

When you had the timing checked, did you check the vacum advance?

 

I'm not sure about that one, I just took it to the local shop and dropped it off for them to check the timing. What is and how do I check the vacuum advance? At least when I'm talking to the shop I won't sound like a dummy. At least not to bad anyway.

 

Vacum advance is on the distributor. You can unplug the vacum line and suck air though it, if air comes though it's bad no air and the insides of the distributor moves it should be good.

 

Your water pump may have an air pocket in it. With changing all the hoses and thermostat, an air pocket could have formed or worked its way into the water pump. I've had this happen to me a couple times while doing work on cooling system. If the system is not primed, the pump will spin and not grab enough water to circulate through the block. When you start the eng - rev it to about 2500 for 3-5 minutes and watch your temp gauge. It should start to rise about mid way through the gauge, then sharply go back down. If this does not happen, chances are there is an air pocket in the pump. Let the eng idle and try turning the defrost on and on max temp. Check your hose on the passenger side of radiator - if it is full of pressure or hard to squeeze, the radiator water is not getting to the block. Two things can cause this, a defaulty thermostat, or water pump. You should be able to squeeze the hose almost closed and feel the water rushing through it. If that happens, then your thermostat and water pump are functional. Shut down eng before it overheats and try to prime the system. Fill it up with more water/coolant and keep trying until you can verify that water is actually flowing through the eng.

Another thing to check is the serpentine belt installation. It is possible to install the belt the wrong way - thus spinning the pump in reverse and restricting water flow. The belt diagram should be posted under the hood near the fan cowling.