Mechanics

OVERHEATING

2000 Ford Ranger • 3.0L 6 cylinder RWD Automatic • 145,000 miles

My truck is over heating and I do not know why. I have changed out the thermostat, I have ran it with out the thermostat, it has a water pump that was just put in this summer, I have bypass the heater core as well and it is still over heating. Where else should I look? I need my truck for work and it is causing issues any help would be appreciated
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Krezlar
February 17, 2014.




You need to provide some details or observations, otherwise there is no way to diagnose this over a computer. Bypassing the heater core will make any overheating worse. That's a small radiator that you just took out of the system.

What are the indications it's overheating? Do you see bubbling in the coolant reservoir? If so, does that occur within a couple of minutes of starting the cold engine or not until you've been at highway speed for a while? If there's bubbling in the reservoir, is there steam too? Does the upper radiator hose feel really hot? It should be too hot to hold onto for very long. Feel across the radiator for cold spots. Is the shroud around the radiator fan missing?

Caradiodoc
Feb 17, 2014.
Shroud is there, the top hose does get hot and hard. No bubble sin coolant. My truck will slowly warm up and then just keep right on going there is no maintaining. So I should hook the heater core back up but if it is broke could that cause my issue as well but even bypassed it overheats.

Tiny
Krezlar
Feb 19, 2014.
If the heater core is leaking, it can allow air to get into the system. If that air pools under the thermostat, (same as if a cylinder head gasket is leaking), it will prevent the thermostat from opening. Thermostats must be hit with hot liquid to open.

When the engine is hot, feel across the radiator to see if there are cold areas indicating some of the tubes are plugged. If the entire surface is hot all the way down to the bottom, the radiator isn't giving up its heat to the surrounding air. That is due to corroded and crumbling cooling fins. Also try pinching the heater hoses. The heater core poses some restriction to coolant flow. With it bypassed, coolant may be circulating too easily through those hoses and is not going through the radiator.
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Caradiodoc
Feb 19, 2014.

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