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Car is running hot.

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Old Jul 23, 2017 | 05:46 PM
  #11  
dawson1112's Avatar
dawson1112
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Chances are you have a partially plugged radiator,, especially if the car sat for that long,, With a cool engine,, open the petcock on the radiator, that is the side that fills up with crud. If it doesnt drain or drains very slowly then it is more likely than not that the radiator is just plugged up with sediment from sitting around. Likely the heater core as well. Back flush the entire system and run some flush and fill through it.

Another way to tell if its the radiator is to run the car till hot, shut it off, and feel around the radiator for cool spots. where ever its cool to the touch no coolant is flowing through that part.
Old Jul 24, 2017 | 12:31 AM
  #12  
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Originally Posted by imp
Narrow down the possibilities. Clogged radiator least likely, IMO. Pump a possibility. If you don't mind wasting some coolant, run eng. till hot, thermostat open, have radiator cap OFF, upper hose clamp loosened plenty at radiator, also having manually twisted loose, so the hose may be pulled off the rad. neck.


Shut down eng. allow liquid levels to stabilize maybe 5 minutes. Have someone start eng. while you immediately slip upper hose off rad. neck. Even at idle, pump should be moving a pretty good flow of coolant, perhaps like an average garden hose open at the end. If just a dribble, pump is likely the culprit. If flow prodigious, look into radiator. A radiator shop ought to be able to acid dip, clean it, for much less than the replacement cost.

If you do this, WEAR LEATHER GLOVES, be careful. imp


EDIT: If rad. clogged, pump will draw considerable about of coolant from outlet tank, push it out of top hose, but flow will slow down quickly.

OK, since no one is "shooting at this one (yet)", a good amendment might be the pump output check would best be done with NO THERMOSTAT. That allows the check to be done basically "cold", safer, less imponderables (was the stat open?), not much extra work involved.


Regarding water pump capacity, Ford often rated pumps at about 20 gallons per minute flow rate, at 1500 to 2000 pump rpm. Since the pump pulley is usually ~ 3/4 the diameter of the crank pulley, the pump turns faster than the engine by about 30%. So even at eng. idle speed of say 800 rpm, the pump is turning way over 1000 rpm, meaning about 10 gpm flow, about like an average-running garden hose. One can SEE and ESTIMATE this flow rate. imp
Old Jul 24, 2017 | 09:34 AM
  #13  
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Mark 95 GT convertible
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Thank you all for the suggestions. Do you think running hot (assuming an obstruction of some kind in the system) could also raise the oil pressure? It is running a little higher than normal. I changed the oil and filter and it dropped a little, but the needle isn't closer to the middle of the gauge like I think it was when I last drove it 6 years ago. Once again, car is 100% stock, and sat for basically 6 years, with only occasional movement while I painted it. In the last 6 years I've driven it maybe 10 miles moving it around.
Old Jul 24, 2017 | 09:51 AM
  #14  
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Running hot typically lowers oil pressure as the viscosity drops as the oil heats up. The stock gauges are not good indicators of what is truly happening. Pick up an infrared gun to see what the temp of the tstat housing is to check the accuracy of your gauge. This will also be a good tool for checking the rad for cool spots. Also the oil pressure prob could be caused by sludge build up while sitting for a while. But a mechanical test gauge is again the best way to get accurate oil pressure readings. Another great diagnostic tool to have in the tool box.
Old Jul 24, 2017 | 01:48 PM
  #15  
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Mark 95 GT convertible
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Originally Posted by mongolchuck
Running hot typically lowers oil pressure as the viscosity drops as the oil heats up. The stock gauges are not good indicators of what is truly happening. Pick up an infrared gun to see what the temp of the tstat housing is to check the accuracy of your gauge. This will also be a good tool for checking the rad for cool spots. Also the oil pressure prob could be caused by sludge build up while sitting for a while. But a mechanical test gauge is again the best way to get accurate oil pressure readings. Another great diagnostic tool to have in the tool box.
I've never heard of a mechanical test gauge for oil pressure, other than one that is attached to your car. How does it work? That's a really good idea.
Old Jul 24, 2017 | 05:16 PM
  #16  
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Mark 95 GT convertible
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After reading all of your advice and opinions, I've decided to replace the radiator. A new one is only $120 or so. The car is 22 years old with 99,500 miles, and for the last 6 years has basically been sitting, so I don't think it's a waste of money. And, mongolchuck, thanks for the info on the oil pressure testing gauge. I didn't know it existed, and NAPA has one for about $80. Like you said, a good tool for the tool box. I do much more painting and body work than mechanical work, so I appreciate everyone's suggestions.
Old Jul 27, 2017 | 12:09 AM
  #17  
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Mark 95 GT convertible
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I put my new radiator in today, and that solved my problems. Idling with the a/c on full blast the water temp gauge barely made it to the half way mark. I bought mine from NAPA, and it was $118. It is a perfect fit in every way, just like the Ford part it replaced. With the new t stat, flushing the system, and the new radiator I should be good for another 20 years. Thanks everyone for the helpful suggestions.
Old Jul 27, 2017 | 08:46 AM
  #18  
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glad you got it figured out
Old Jul 29, 2017 | 07:51 PM
  #19  
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Mark 95 GT convertible
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Well, an update on my cooling issues. I got plates yesterday, and for the first time in 6 years, drove my car today. Unfortunately, the gauge went back up to the red zone, and even the service engine soon light came on. A friend suggested an infared thermometer, and I bought one today at Auto Zone. It was only $31, and I checked its accuracy by pointing it at a pot of boiling water-it is within 2 degrees. Anyway, I drove the car again, it got hot (according to the gauge) again, and the service engine soon light came on again. I pulled over, and it showed 198 degrees. The car has a 195 degree thermostat, so obviously it isn't overheating. So, that leads me to my next question-is there some kind of sensor that may have gone bad that sends information to the gauge? I refuse to drive it and just assume everything is ok, because of course if something really does go wrong, I'll not know until its too late. Same issue with the oil pressure-the gauge just kind of moves around. Any more help you guys can give I sure would appreciate!
Old Jul 31, 2017 | 02:00 PM
  #20  
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Can't really help you here. You can try new sending units for both but, I won't promise that will fix it. Maybe in the gauges.
Actually the working half the time and not the other makes me lean more towards the gauge itself but, I would try a sending unit first. If it is like the fox, it will be towards front of the intake, pass the injectors. It will have one wire.

Last edited by TrimDrip; Jul 31, 2017 at 02:02 PM.
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