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Cooling System Issue?

broncosam

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Feb 8, 2005
Messages
1,178
The boss and I took the Bronco out for a drive yesterday evening to grab a bite to eat and see some friends. It was about a 10-15 mile drive to the place we wanted to eat at. I backed into a parking spot and as I was walking past the front end I noticed something dripping under the Bronco. I opened the hood and the coolant recovery tank was overflowing. It had never done that before. The radiator was warm to the touch but not so hot you could not leave your hand on it. According to the engine temp gauge it was running around 180 degrees, the outside temp was in the low 80's. It has never did this before even driving it in temps well above 90 degrees. The temp gauge has always stayed around 180. I have never changed anything on the cooling system except for putting a new 13lb. radiator cap on. The Bronco has what looks to be a 3 or 4 core radiator with a full shroud and a 6 blade flex type fan, this was all from a PO. I don't know what thermostat is in it. But as I said it was puking coolant out of the recovery tank and then on the way home if I was stopped at a traffic light the temp gauge would start going up and got as high as 220 degrees. It has never been that high before but I made it home without it overheating. One other thing I will add is that mt Bronco has a Dakota gauge cluster in it installed by a PO and I don't know if it is reading true or not. I know the fuel gauge does not and the speedo has never read true. This is just out of the blue but am I looking at a thermostat issue, possibly gone bad, that's what I'm thinking.
 

brncofinatic

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Dec 8, 2004
Messages
90
You said you replaced the cap. How long ago? suppose it could be the cap not holding pressure? You might try another cap before tearing into the thermo housing. Just a thought.
 

Broncobowsher

Total hack
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Jun 4, 2002
Messages
34,835
Not all caps are for use with a coolant recovery tank. There needs to be 2 gaskets, one spring loaded in the center for pressure control and another that seals against the top of the neck. A true original style cap on a Bronco that didn't originally have a recovery bottle probably doesn't have that upper seal.

The really quick answer, you are likely low on coolant. Fill it up, keep an eye on it.
The really bad is if it keeps blowing coolant out without overheating, that could be something like a head gasket starting to fail and blowing compressing into the cooling system which in turn is pushing coolant out. That is typically best found with a leak down test with the radiator cap off. If you get a cylinder that causes the coolant to start to rise when doing a leak down, time to pull the head.
 

DirtDonk

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Bronco Guru
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Nov 3, 2003
Messages
47,355
Do you have a standard bronco recovery tank?
Many of the aftermarket ones are very small and might be easily overfilled. So coolant simply coming out of the recovery tank is not necessarily unusual.
But it can be. Definitely check the cap as was mentioned.

Unrelated to your question but related to your comments about the Dakota Digital, get the instructions and re-calibrate your speedometer.
It’s a simple, but a little fiddly operation and should only take you a little while to accomplish.
The fuel gauge issue could be several things but the first thing I would do would be to make sure the gauge is calibrated for the 73–10 ohm rating of a factory sending unit.
 
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broncosam

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Feb 8, 2005
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As far as I know it's a standard factory installed recovery tank. I am going to wait until tomorrow to try and sort this out. May go on and get a new radiator cap and thermostat and swap them out and hope it's not a water pump or as Broncobowsher said, possibly a head gasket going. I haven't seen any oil in the coolant yet or coolant in the oil, gonna keep an eye on that.
I'll look at the Dakota website and see what I can come up with to try and correct any calibration issues.
 
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broncosam

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Feb 8, 2005
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Update, I put a new 180 degree thermostat in the Bronco this morning along with a new 13lb. rated radiator cap. Took it out for a short drive, everything seemed fine, temp gauge never got above 180. The old thermostat was a 160 degree piece. Going to take it out tomorrow and drive around a good long while to see how it does. Hopefully the old thermostat was the issue.
 

Broncobowsher

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Jun 4, 2002
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The stock gauge is not known for the greatest accuracy as well. Once you know the "normal" for your gauge, you will know when things are not normal.
 
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broncosam

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Feb 8, 2005
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The stock gauge is not known for the greatest accuracy as well. Once you know the "normal" for your gauge, you will know when things are not normal.
I don't have a stock gauge. My Bronco has a Dakota gauge cluster in it. A PO installed it. I like the looks of the stock gauge cluster much better and my plan is to install a new wiring harness somewhere down the line, when I do that Dakota thing will be gone.
 
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