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Old 05-16-2016
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Join Date: Apr 2014
Location: San Diego
Posts: 1
2003 2.3 keeps overheating

I have read through all of the forums to see if they would be of help, nope.
So my ranger has been overheating. I have replaced the water pump, thermostat housing, t-fitting, coolant temperature sensor, cylinder head temperature sensor, and I did a coolant flush.
The coolant flush that I did was with the flush chemical where you run it for a few days and let it do its work to get everything out. I just let it drain from the lower drain plug. I changed it out about 6 times until it came out completely clear, I then put in green coolant. Still overheating.
The reservoir is filling up and will overflow after driving it for about 30 minutes, and it doesn't look like it's pumping water very hard. If I pull the upper small reservoir hose off and blow into it, everything comes out from the radiator, so I do not think that the radiator has a clog.
Could it be possible that the engine block as a clog? Would that be causing the reservoir to overflow?
Im losing my mind over this and spending way too much time on it.
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Old 05-17-2016
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Join Date: Apr 2016
Location: Lake Worth
Posts: 644
Diagnose Cooling Fan Clutch

Test your fan clutch and make sure you are running the correct 50/50 mixture of coolant-distilled water straight coolant without water will raise the boiling point.

you may want to pressure test the cooling system and pressure cap.
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Old 05-17-2016
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The reservoir is filling up and will overflow after driving it for about 30 minutes
Do the Glove test to take blown head gasket off the table
Cold engine
remove rad cap
remove overflow hose and plug that port with vacuum cap or ??
Drain some coolant out so it is down about 1", lower is fine.

Put latex glove over rad cap opening and seal it with rubber band, you can use a balloon or even a condom instead of a glove.

Start engine
If glove inflates then you have a cylinder leaking pressure into cooling system.

A cold engine has no pressure in cooling system, the pressure comes from the coolant heating up and expanding, which takes about 5 to 8 minutes of engine running.
A water "pump" is not really a pump, it is a circulator, like a ceiling fan in your house, it doesn't create high pressure in your house, it just circulates the air.

If glove inflates shut off engine
Pull off spark plug wires
Crank engine and glove should bounce
remove 1 spark plug at a time and crank engine
When glove stops bouncing then last spark plug removed was from leaking cylinder, put it back in to confirm.

This can be helpful when looking for leak point after disassembly

Last edited by RonD; 05-17-2016 at 12:29 PM.
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