cooling problems

[funnycar]

I have a 1975 Bronco with a 392-450 hp. motor. It has a two core ( 1" wide) alumn. rad. This runs around 230 deg. going down the road and will not recover. Cant drive it in the weather here in Texas durning the summer.

Thanks

Funnycar:

 

[Pa PITT]

Well 1st I'll say welcome aboard... When I read your report I thought he must be in Texas... Mine overheated so maby time I gave up & put in the Diesel..
... It's kind of early for this post but.. Since you have a stretched motor..
.. I want to see if there is any new ideals ..

 

[moses_m]

What thermostat 180 190?
Electric fan? Standard fan? Clutch fan?
Shroud?
Which water pump?

 

[ScanmanSteven]

4 core BCBroncos should do the trick.

 

[broncnaz]

Id also ask for more info. We can all throw out possibilitites. But it could be something simple and we need to know whats already been done and just more background.
Have you done anything to remedy the issue? New parts? Is the engine tuned correctly Jetting timing ect? Other engine specs comp ratio? cam? ect.

 

[Broncobowsher]

More info would really help.
Better yet post some pictures.

There are a LOT of variables in a Bronco cooling system. Something as simple as a cowl induction hood open at the rear can cause highway cooling issues. Many cooling fans have been installed backwards without knowing it was even a problem. That's without even getting into how well the engine is tuned, which can further push the cooing system capacity.

 

[Bonco4Broncos]

Yep what everyone else has said and also maybe add a electric fan also. All electric fans are not created equal either. Get a good quality one. The bigger the better...

 

[wgamble]

If all else fails, drill a small hole in your thermostat.

 

[DJs74]

As everyone has stated... more information is needed to offer the best help. In the meantime, some questions or things to consider:
* how are you concluding 230°F - factory or aftermarket gauge / senders?
* fan shroud installed?
* thermostat rating?
* do you have good heat inside? (if only lukewarm, could be stuck thermostat or not fully opening)
* fan type, factory or aftermarket, clutch or fixed?
* coolant type? 50/50 or straight?
* have you purged the coolant system?
* overflow tank installed?
* what is your timing?
* Is it A/T or manual, auxiliary transmission cooler installed on radiator / air flow restrictions?
* any heater core issues - potential clogs in the system>


DJs74

 

[74strokerbronco]

I would like to add one that is often missed, if you got a bad/no heater core and have looped your hot water outlet back to the water pump with a hose you are recycling HOT water right back thru the motor . when you don't utilize the heater core the outlet and pump inlet should be capped off not looped with a hose. The hot water outlet on the intake manifold has water at or above thermostat level ,and when looped to the water pump suction is adding a half inch hose flow of HOT water right back into the water pump suction that never gets cooled, making it act like the radiator is not doing it's job, when it has to flow thru a heater core the core removes lots of heat from the water before it is returned to the water pump.


back in my street car days when we had a street car that didn't want to stay cool in stop and go traffic we would take a large heater core and place it in front of the radiator or somewhere else with a electric fan and hose it in just as if it was a normal heater core i.e. intake manifold hot out and return to pump. this way the core was cooling all the time but not into the inside of the car . almost always solved the issue . think of it as a small auxillary radiator.

 

[Pa PITT]

... Wow I'm glad I read these... never seen the the axy core.

 

[Apogee]

Adding an auxiliary engine oil cooler can be a good way to reduce operating temps as well if you ever run out of things to do with the radiator and rest of the cooling system.

 

[broncnaz]

I dont buy the heater core issue. At least not in broncos. As with the stock setup the heater core doesnt see any flow when the valve is closed anyhow. I can see having the system looped and having a issue but if adding a aux heater core fixes the issue then your issue was that your radiator doesnt have enough cooling capacity to start with either because of size or blockage.
The heater core really shouldnt be relied upon for cooling capacity.

 

[ntsqd]

Engine oil cooler is a good plan. There is a LOT of heat that the oil picks up. Adding a cooler for it takes some of the load off the radiator. EFI 460's have a nice angled adapter with a thermostat built-in. Too bad I'm told they don't fit the EB chassis. Maybe by twisting it?

With a cooling system that otherwise could keep up with all demands on the engine I've had to use the heater core to keep the engine cool in several vehicles and specific instances. I see adding one specifically as an aux radiator as likely very effective if a bit shade-tree.

If all else fails, drill a small hole in your thermostat.

I do this with the edge of the hole *just* at the edge of the gasket, and always put the hole at the top when installing. Makes the system self-purging of air bubbles. 1/8" is what I drill.

 

[u0061914]

I would like to add one that is often missed, if you got a bad/no heater core and have looped your hot water outlet back to the water pump with a hose you are recycling HOT water right back thru the motor . when you don't utilize the heater core the outlet and pump inlet should be capped off not looped with a hose. The hot water outlet on the intake manifold has water at or above thermostat level ,and when looped to the water pump suction is adding a half inch hose flow of HOT water right back into the water pump suction that never gets cooled, making it act like the radiator is not doing it's job, when it has to flow thru a heater core the core removes lots of heat from the water before it is returned to the water pump.

Glad I read this. I do not have a heater core and it is looped back to the water pump. Even with a good fan, aux fan, different radiators, backed off with the timing etc, I have always had issues with mine running a bit warm ( 351C). I am going to change that and see if that solves my issue.

thanks!!!

 

[70_Steve]

Had a friend who had a beautiful 55 Chebby restomod with a 383. Always had cooling problems at speed. Would idle OK.

Bottom line was, the radiator (brand new Be-Kool radiator) was damaged during factory pressure test. The tubes were over-pressured and expanded. This cut down the air flow through the radiator to the point where it couldn't pass enough air to cool with the extra load at speed.

A different radiator solved his problem

 

[74strokerbronco]

I dont buy the heater core issue. At least not in broncos. As with the stock setup the heater core doesnt see any flow when the valve is closed anyhow. I can see having the system looped and having a issue but if adding a aux heater core fixes the issue then your issue was that your radiator doesnt have enough cooling capacity to start with either because of size or blockage.
The heater core really shouldnt be relied upon for cooling capacity.

my point was the loop, not a intact heater system with a flow valve, obviously with the valve closed when it is present is the same as capping off the system. I have seen it many times were for some reason either because of a faulty flow valve or core leak someone has looped the system and then fights over heating issues not realizing they are recirculating a hose flow of hot water. And even with a radiator that is adequate otherwise if you loop, then the radiator is not seeing that portion of the hot water to cool and your reintroducing that hot water right back into the block.

I agree that you should not have to rely upon the heater core to provide cooling but it is part of the system , I once went across the sever desert in Utah on a 127 degree day in a diesel Isuzu car that was nearly brand new and when pulling grade the ONLY way to keep it from over heating was to run it with no a/c and the heater on full blast full fan, it was not a comfortable ride but the small amount of extra cooling saved the day and the vehicle never had a heating issue otherwise .

ntsqd, yeah it was shadetree by a just out of high school kid (me) but it worked and my budget was limited and could not afford a newer larger radiator, it was a 67 mustang with a solid roller 351 Cleveland and a radiator out of a 390 car, but in stop and go traffic on a hot summer eve, even with a 6 blade fan and shroud it would overheat otherwise it was fine in all other driving conditions. so knowing the cooling system was just on the edge of adequate I added a large heater core from something on the farm and mounted it and it solved the issue, yes the real solution was a better radiator but you do what you have to sometimes even if a little shadetree.

 

[sykanr0ng]

BIG engine + small radiator + Texas = cooling problems

Big engines need big radiators.

Nobody has asked and you didn't say, what front dress is on that engine?

The Explorer serpentine is good because it comes with an excellent fan and puts it at a good distance from the radiator.

 

[74strokerbronco]

Glad I read this. I do not have a heater core and it is looped back to the water pump. Even with a good fan, aux fan, different radiators, backed off with the timing etc, I have always had issues with mine running a bit warm ( 351C). I am going to change that and see if that solves my issue.

thanks!!!

Let us know how it works out for you. . .

 

[jw0747]

Funnycar, I'm in Texas too and don't have an overheat problem. I'd certainly like to help you but we need some info from you to recommend stuff. What items are included in your current cooling system beside your radiator ie. thermostat, type of fan, do you have a fan shroud etc? Let's hear from you.