Overheating. I need suggestions.

[71mach351]

My car started overheating this weekend on the way to a show. What's weird is that it's fine at idle but when I start to drive the temp pegs.  Overheated on the interstate and when I pulled off into traffic  it cooled off!

I changed the rad cap and thermostat and refilled with new coolant and it still happens.

Any ideas?

 

[73pony]

Did you put in the correct T-Stat? If you have a Cleveland the ones the parts stores sell off the shelf are for a Windsor despite what they say.

 

[waterlife]

Engine size?

 

[71mach351]

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.

 

[Jeff73Mach1]

Have you run it with the radiator open so you can see coolant movement? Have you checked your oil for contamination?

 

[71mach351]

Have you run it with the radiator open so you can see coolant movement?  Have you checked your oil for contamination?

Oil is still nice and clean.  There is some barely noticeable 

flow with the cap off.  I can let it run at idle all day long it the gauge is fine.  I'm thinking the radiator is shot.  The fan at idle is enough to compensate for the bad radiator but at speed the normal air flow isn't enough.

 

[73pony]

When you replaced the stat was the restrictor plate there and seated properly? I am still running my original 73 radiator with no issues at all on a heavily modified motor.

 

[71mach351]

When you replaced the stat was the restrictor plate there and seated properly? I am still running my original 73 radiator with no issues at all on a heavily modified motor.

Yes the restrictor is seated.  The engine and cooling system have work flawlessly for years. Never had an overheating issue.  This just started Saturday.

 

[Jeff73Mach1]

I'm leaning towards a bad water pump or a stuck thermostat Water will bypass the thermostat slowly and will potentially be enough at idle to keep engine cool, but under load could not keep up. Doubt the radiator is the source of the problem.

 

[waterlife]

I would change the restrictor plate, easy and cheap, known issue in the 351c

 

[EBSTANG]

I would change the restrictor plate, easy and cheap, known issue in the 351c

If the restrictor plate is seated, there would be absolutely no need to change it .  They don't go bad, they can only become dislodged from their press-fit.

 

[EBSTANG]

I'm leaning towards a bad water pump or a  stuck thermostat   Water will bypass the thermostat slowly and will potentially be enough at idle to keep engine cool, but under load could not keep up.  Doubt the radiator is the source of the problem.

I agree.  Bad pump, as your problem came on abruptly. Stuck thermostat, as that can also happen abruptly.  Even a new thermostat can be faulty, it's best to test it...pretty easy to do.

 

[71mach351]

I agree it's not the restrictor.  Thanks for the ideas.  I'm going to put the original thermostat back in since I've tested it and it opens at 195.  Looks like a water pump is next, fairly cheap.  Might as well flush the radiator while its drained.

 

[waterlife]

I would change the restrictor plate, easy and cheap, known issue in the 351c

If the restrictor plate is seated, there would be absolutely no need to change it .  They don't go bad, they can only become dislodged from their press-fit.

You have no clue!   the plate is an issue from the day they were built, that why they sell completely re- engineered restrictor plates. Ask any Pantera owner, or go the West coast cougar classics and read up on the issue.

 

[EBSTANG]

I would change the restrictor plate, easy and cheap, known issue in the 351c

If the restrictor plate is seated, there would be absolutely no need to change it .  They don't go bad, they can only become dislodged from their press-fit.

You have no clue!   the plate is an issue from the day they were built, that why they sell completely re- engineered restrictor plates. Ask any Pantera owner, or go the West coast cougar classics and read up on the issue.

...to the contrary, I know more about the brass "bypass orifice" than you can imagine.  The only problem you could have relating to the bbo is if it is dislodged or it it missing altogether. Trust me, I totally understand what there is to know about it.  I also know that it is not a restrictor plate. That would be what someone calls it when they don't know what they're talking about.  I was being kind earlier, idiot.   rofl

 

[waterlife]

If the restrictor plate is seated, there would be absolutely no need to change it .  They don't go bad, they can only become dislodged from their press-fit.

You have no clue!   the plate is an issue from the day they were built, that why they sell completely re- engineered restrictor plates. Ask any Pantera owner, or go the West coast cougar classics and read up on the issue.

...to the contrary, I know more about the brass "bypass orifice" than you can imagine.  The only problem you could have relating to the bbo is if it is dislodged or it it missing altogether. Trust me, I totally understand what there is to know about it.  I also know that it is not a restrictor plate. That would be what someone calls it when they don't know what they're talking about.  I was being kind earlier, idiot.   rofl

Here you go dumb Philly loser, try to read, if you can't, have someone read it for you

New water restrictor plate for the Mercury or Ford equipped with the 351 Cleveland engine. It has been an accepted fact for decades now that the 351C bypass system was not the greatest idea Ford ever came up with. The unique 351C thermostat "hat" never seals well, causing a certain portion of coolant to just circulate through the block and never make it to the radiator. Years ago, Pantera enthusiasts (all Panteras had cooling issues from the factory BTW) found that if they soldiered a penny into the hole in their restriction plate and used a standard small block Ford thermostat, their cooling issues all but disappeared. That trick worked fine until Ford discontinued the brass restrictor plate. This aluminum unit is designed to replace the brass plate and be installed as-is. This unit must be used in conjunction with a standard thermostat , you cannot use the 351C unique thermostat with this block off plate. The tiny hole in the center is for air bleed only. 

 

[Don C]

I would change the restrictor plate, easy and cheap, known issue in the 351c

If the restrictor plate is seated, there would be absolutely no need to change it .  They don't go bad, they can only become dislodged from their press-fit.

You have no clue!   the plate is an issue from the day they were built, that why they sell completely re- engineered restrictor plates. Ask any Pantera owner, or go the West coast cougar classics and read up on the issue.

I disagree. I had no problems when I lived in Las Vegas. The only problem arises when a Windsor thermostat is used.

https://www.7173mustangs.com/thread-351c-cooling-system

 

[EBSTANG]

You have no clue!   the plate is an issue from the day they were built, that why they sell completely re- engineered restrictor plates. Ask any Pantera owner, or go the West coast cougar classics and read up on the issue.

...to the contrary, I know more about the brass "bypass orifice" than you can imagine.  The only problem you could have relating to the bbo is if it is dislodged or it it missing altogether. Trust me, I totally understand what there is to know about it.  I also know that it is not a restrictor plate. That would be what someone calls it when they don't know what they're talking about.  I was being kind earlier, idiot.   rofl

Here you go dumb Philly loser, try to read, if you can't, have someone read it for you

New water restrictor plate for the Mercury or Ford equipped with the 351 Cleveland engine. It has been an accepted fact for decades now that the 351C bypass system was not the greatest idea Ford ever came up with. The unique 351C thermostat "hat" never seals well, causing a certain portion of coolant to just circulate through the block and never make it to the radiator. Years ago, Pantera enthusiasts (all Panteras had cooling issues from the factory BTW) found that if they soldiered a penny into the hole in their restriction plate and used a standard small block Ford thermostat, their cooling issues all but disappeared. That trick worked fine until Ford discontinued the brass restrictor plate. This aluminum unit is designed to replace the brass plate and be installed as-is. This unit must be used in conjunction with a standard thermostat , you cannot use the 351C unique thermostat with this block off plate. The tiny hole in the center is for air bleed only. 

It's nice to see that someone has taught you to copy/paste!   rofl   ...and use big font!!!  There is hope for you. :shootself:  Now, back to the author's post. His problem came on this past weekend and he never had this problem before (this is a hint)...to solve THIS problem you thought you'd speak up and show everyone that you know about the Pantera Block Off Plate.  Congratulations for knowing and remembering something that you have read!!!!  I am very happy for you. :bravo: The only problem is we all also know about this Block Off Plate and the author's problem is not attributed to not having one. I am glad that you remembered about it though.  Maybe next time you can interject your opinion with an idea that might solve the problem at hand. There are many posts about the aluminum Pantera Block Off Plate, if you read a bit more you might be able to advise someone and help them as opposed to leading them down a rabbit trail of frustration.  Oh, and to be clear, I am not saying that you cannot use the Pantera Block Off Plate and have success, rather I am stating that this is not the problem asked about by the author of this post. Isn't that the issue at hand?  You could write a post and tell us all about the Block Off Plate if you'd like. (you can even copy/paste more info) because we know you like to do that!   :lol:

Remember, you started this by stating,  "You have no clue!"                           Oh look, I can copy/paste too! ::thumb:: ::tease::

 

[piper62j]

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