Cooling question, 78 Bronco add electric fan?
 

Finished installing new heater core yesterday.
Let Bronco idle in the driveway for 10-15 minutes while I refilled the little bit of anti freeze I lost replacing the heater core.
It gets way too hot just sitting there.
Only high 60s air temp and temp gage and my laser thermometer to verify showed nearly 230.
:(
New water pump, thermostat 165 degree, radiator is only a few years old, new hoses, new heater core now, factory clutch fan with shroud.
Can see great flow through radiator and stat opens when it should.
Just seems like not enough airflow through the radiator when sitting still.
Driving it seems to stay cool enough when moving.
Thinking either fan clutch... looks like it is locking up and spinning the blade OK or
Should I look into adding an auxiliary electric fan in front of radiator...?
If so, anyone done same with good luck?
I know Taurus set ups seem popular for everything.
See prices all over the place.
I know I don't want to go too cheap.
My little 75 Bronco was set up with one that just did not move enough air to matter at all.
Appreciate any help
THANKS


BTW...forgot to mention.
Bronco has somewhat modified/built 460
Lumpy cam, holley, Edelbrock intake, msd ignition, L and L headers, flowmaster exhaust.
Automatic.
Originally 400 mod motor
no a.c.
Think that is most of the relevant stuff.
I have another thread where I listed block and head casting IDs wondering if I could figure out what each were originally.
Thanks again

My suggestion would be to flush the entire cooling system. There is a product (evaporust available at summit) that you put into your cooling system drive for about 3-5 days then flush. I did this to my 78 bronco and you be surprise all the rust and junk that came out of my cooling system. It cleaned my champion aluminum radiator like it was brand new instead of 4 years old.
Only a suggestion. Also electric fans a great there are pro and con's to there use. Clutch fan work but put a load on the water pump bearing, electric power draw is not that noticable, but you have to have a good controller to rum them, and a fan shroud, either one 17 in fan or duals 12.5
my opinion only

I had been thinking of trying Prestone minute flush. I had used that a few times over the years trying to clean out cooling systems.
Had not heard of using the evaporust in a radiator, but maybe look into that too. I just hate to mess around too much with stuff and not get the results. Hate to flush the system and not have it work any better. Same with fans, replacing parts etc. Appreciate the info. and product heads up. THANKS ! ! !

do you have the stock fan shroud on it. if not then you need it. go up on the temp of the thermostat, its opening too early and not giving the radiator a chance to cool. did you go up on the size of the radiator for the 460. add-on cooling electric fan can help. i would bypass the heater core if your going to flush your system. that stuff is hard on heater cores.

It does have factory shroud. Not 100% sure if radiator was upgraded at all. That was put in (and the 460) by former owner, a co-worker.
I am guessing it is same as original 351M/400M but can't swear to it. I know that truck has sat a LOT for many years. Maybe I will try just a fresh water flush and new anti freeze soon along with a different stat. Never thought about having too low of an opening temperature.
Thanks again !!

My buddy up in Washington state put a 460 into his Bronco. It overheated one time when it was about 30 degrees outside.

IMO get a bigger radiator.

Serving suggestion.....

On edit, I should have said "....it overheated regularly, including one time when it was 30 degrees....". If that thing wasn't moving, the temp started to climb.

I guess that certainly could be the issue. Even with the radiator being in good shape and flowing, being too small would keep it from doing the job too. Will look into that possible fix too. THANKS

I've got a 300 hp 400 engine with cam, EFI, long tubes, and A/C... I have a cheap Spectra Premium aluminum 2-row rad with NAPA iron water pump and 180 thermo, live in the hottest part of the country and my '79 Bronco runs nice and cool with dual Contour fans properly shrouded.

I still need to dig into this more.
Haven't really done much with the Bronco since I got it home.
Ordered a few misc parts, pulled tailgate off to fix a few small spots of rust, and only start it once in a while to keep it lubed up.
Got to get at it.

Wondering more and more about the fan clutch.
Had the Bronco idling in the driveway again a few days ago.
When looking from the driver's side over the fender, it looks like the fan blade is only spinning about 1/10th of what the water pump pulley is.
Knowing that the overheating happens at low speed and idling, I am guessing fan just isn't roatating fast enough to move enough air.
Is there any preferred replacement besides a stock clutch?
Anything any better ?
A "flex fan" better or worse than replacing the clutch?
Appreciate any tips or ticks.
THANKS

I'd replace the fan clutch - I wouldn't go with a flex fan or anything like that. If the radiator is old it could be need a thorough cleaning, rodding out, or replacement.

After seeing it spin so slow I figured I would replace it.
Just wondered if there was another application, 3/4 or 1 ton truck, heavy duty, or something bigger better than just stock replacement.

Typically, aftermarkets like Four Seasons and Hayden will have a standard, heavy duty, and severe duty part - I've had luck running the Hayden before... in fact I may have one sitting around in my garage (switched to electric fan) if you need one.

Wow
Appreciate that.
I think I will try to pick up a new one locally so I can see if that helps.
Bronco Take over at Silver Lake Sand Dunes coming up.
Wanna try to make sure this thing is going to make it.
Appreciate the offer.

Replaced the fan clutch yesterday.
:)
Idled in the driveway and gage never reached 170.
Looks like that was it.
Or atleast seems like it so far.
Old clutch was pretty easy to spin.
Had some play and slop in it too.
Plus was greasy and and covered in filth.
Wondering if it didn't leak it's fluid out.
The thermostatic coil spring was out of place too.
Hoping this is what I needed.
I was curious by the time I got done though...
I was assuming that the hotter it got the tighter and more resistance and friction the clutch would apply.
Seemed opposite.
A lot of drag when I put it on cold.
And more free wheeling after I warmed the Bronco up....
Seemed to work OK though.

THANKS again for all the help, advice, and even part offerings ! ! !