Overheating. I need suggestions.

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Engine size?
351c.   Standard 195 deg t-stat. (Stant 13469)  I tested the old one and it was working.

Other info.    Radiator is 24 years old with 24000 miles on it.  Car is stored 6 months a year.  Water pump is 15 years old.
Pull the bottom radiator hose.  They have a tendency to collapse at high speed, inside when they get old and soft...  While you're at it, pull the top hose and inspect it also.. Both should be firm when cool.  When these cars were new, the lower radiator hose came with a coil spring inside to prevent collapsing.. Over the years, that spring has not been remembered, or used..  JMHO
...also a very good idea on a possible remedy. I added one to my lower hose after my rebuild when I added a FlowKooler high volume water pump.

 
+1. I have NO issues with the factory set up. I am still running the original radiator as well. I do have a spring in the lower rad hose as it will collapse with a standard volume water pump which I am also running. There are honestly NO ISSUES with the factory set up on a mustang. The Pantera issues involved block placement, I.E. back of the car and insufficient cooling system in radiator design and engine placement. Not the case in a mustang. This is on a heavily modified engine.

 
Friend got same prob years back on a 327 camaro 67. The car was park like 8 months per year.

While pump, hoses, thermostat probs must investigated for sure, turns out his coolant somehow coagulated like blood in block. Fix was simply to disconnect radiator hoses, thermostat housing and flush the system with fresh water hose from his house till water that came out clear from block and radiator.

Not saying thats the case here, but its so easy and quickly done, it may save you the trouble and costs to change your pump, plus you then have a clean system...

 
Just in case anyone was wondering, there is no prize for being right. Disagreements shouldn't get personal here. I am not a moderator, nor do I have or want any authority, but if I had it, this thread would be closed and two posters would be getting nastygrams from me.

 
Just in case anyone was wondering, there is no prize for being right.  Disagreements shouldn't get personal here.  I am not a moderator, nor do I have or want any authority, but if I had it, this thread would be closed and two posters would be getting nastygrams from me.
Jeff. I innocently replied to a post. Waterboy responds by posting, "You have no clue!"  I will defend myself, you know me better than that.  Waterboy should be the only one receiving a "nastygram."  All the moderators on here know that I don't start that kind of bullsh*t, ever. I will not back down though and whether it's face-to-face or word-for-word, proceed with caution.  I am always quick to let it go, if the instigator recinds.

 
Last edited by a moderator:
I mostly agree with you. But "Idiot" crosses a line that makes returning hard. Your nastygram would have been the milder one. But as I said before, I'm nobody when it comes to authority on this board. I just don't like seeing people throw trash out on the playground.

 
And now back to our regularly schedules cooling issue.

I checked the hoses.  Bottom one does have its spring in it.  Top one is in good shape.  Took it out again today.  Let it warm up for about 3 minutes. No movement on the gauge.  Backed it out of the garage and sat for 2 minutes in reverse.  Gauge came up quickly to 1/2 scale.  2 minutes of driving at no more than 30mph and the gauge was hot.  Parked it in the garage at idle and the gauge came down to 1/2  scale.  Radiator was not hot.  Engine was hot but seemed Ok.  I wish I had an IR temp gauge.

Maybe a bad sender?  This is frustrating.

 
And now back to our regularly schedules cooling issue.

I checked the hoses.  Bottom one does have its spring in it.  Top one is in good shape.  Took it out again today.  Let it warm up for about 3 minutes. No movement on the gauge.  Backed it out of the garage and sat for 2 minutes in reverse.  Gauge came up quickly to 1/2 scale.  2 minutes of driving at no more than 30mph and the gauge was hot.  Parked it in the garage at idle and the gauge came down to 1/2  scale.  Radiator was not hot.  Engine was hot but seemed Ok.  I wish I had an IR temp gauge.

Maybe a bad sender?  This is frustrating.
 I think you should replace the restrictor plate.

Just kidding.  :D   I couldn't resist.  Seriously, just kidding.dancebanana

 
And now back to our regularly schedules cooling issue.

I checked the hoses.  Bottom one does have its spring in it.  Top one is in good shape.  Took it out again today.  Let it warm up for about 3 minutes. No movement on the gauge.  Backed it out of the garage and sat for 2 minutes in reverse.  Gauge came up quickly to 1/2 scale.  2 minutes of driving at no more than 30mph and the gauge was hot.  Parked it in the garage at idle and the gauge came down to 1/2  scale.  Radiator was not hot.  Engine was hot but seemed Ok.  I wish I had an IR temp gauge.

Maybe a bad sender?  This is frustrating.
 I think you should replace the restrictor plate.

Just kidding.  :D   I couldn't resist.  Seriously, just kidding.dancebanana
Stir that pot.  At least this is entertaining.  

I can throw 2 water pumps at this for the price of one plate.

 
yeah, the IR thermometer is a good idea, and only tends to run 15-20 bucks.

When the engine is warm and running can you feel water flowing though the lower hose?

If it is the radiator (which I doubt) you could try turning the heat on full blast and see if this brings the temperature down. If the water pump is bad it will not and there will be little heat.

 
And now back to our regularly schedules cooling issue.

I checked the hoses.  Bottom one does have its spring in it.  Top one is in good shape.  Took it out again today.  Let it warm up for about 3 minutes. No movement on the gauge.  Backed it out of the garage and sat for 2 minutes in reverse.  Gauge came up quickly to 1/2 scale.  2 minutes of driving at no more than 30mph and the gauge was hot.  Parked it in the garage at idle and the gauge came down to 1/2  scale.  Radiator was not hot.  Engine was hot but seemed Ok.  I wish I had an IR temp gauge.

Maybe a bad sender?  This is frustrating.
 I think you should replace the restrictor plate.

Just kidding.  :D   I couldn't resist.  Seriously, just kidding.dancebanana
Stir that pot.  At least this is entertaining.  

I can throw 2 water pumps at this for the price of one plate.
...definitely try the water pump. I love entertaining!   :banana: :wavemulticolor: :jumpeveryone: ::chili::

 
I'd be buying an IR thermometer....
Good call.  Looks like they're cheaper than I thought.  I'll pick one up and check the actual temps. 

Won't be able to get it going by this Sunday's car show.  Looks like I'll have to take dads Corvette!!!!!  Did I just say that?

 
It would have to be either a bad sender, bad thermostat, or plugged radiator core, since the radiator isn't getting hot and the hoses are good, because it seemed to happen suddenly and not gradually, and you've replaced the thermostat, with no change and the old one tested OK, I'm going with the sender.

 
Try this to test the sender. Pick up a cheapo mechanical temp gauge at the local parts store and install it temporarily and drive to see if that shows the same issue. If not then your sending unit is bad, if it still does it there is something else wrong.

 
Update

I put a new radiator in from my project truck.  Still overheated.  Checked temp with an IR thermometer and it didn't show overheating.  So I started to think maybe and electrical issue.  Yup,  that's it.  I found the ground cable from the battery was no longer attached to the fender apron below the voltage regulator.  I took it for a rip and the gauge stayed dead center.

 
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