Problems with 351 overheating!

[Muddn7]

Heres the scoop:
73 bronco with a 351W and 4 core rad. It has a large electric fan mounted in front of the radiator, and runs at great temps on the highway even with the fan off. I ran into a problem Sunday when my Bronco went out on her virgin run. The battery was junk! The alternator is new, and kept me running without a problem. The problem is, the battery wont hold a charge, so the fan didn't run at full capacity. Hence the 230 degree temp! The Ignition module decided to call it quits, so that added insult to injury! So if I kept her running, she would overheat, if I let her rest, I needed a jump! This was more than an inconvenience to me! Now were onto Monday: I replaced the module with a distributor carrying one from Mallory, new battery of better brand, and I emptied the rad and induced new water. I ran the Bronco up to 210 degrees in the driveway, then turned on the fan. The temperature dropped down to 190 degrees, and held it for more than 10 minutes. Then it decided to go up slowly. It reached almost 220 degrees when I decided to just shut it off before I pulled what hair I had left out of my head. So I have read up on the Bronco for problems and situations like this for years. I am on my fourth Bronco, and several other Fords in the process, but I had yet to run into this problem. Heres what I have come up with that might be a problem......
1. Its all water in the radiator! I have been doing leak checks, and if she keeps boiling over, I am not going to put radiator fluid in the radiator. The leak checks are good, but its an option.
2. The timing is factory at 10 degrees btc. The problem I might see is the pointer! It came off of a 302, due to my motor being without when I bought it! Can my timing be off?
3. Is the 351 just too much heat under the hood? With Hooker Headers, and a scoop with two exit holes towards the rear, I cant see it.
4. Now I am watching the volt guage, and its at 12, with lights on, and the rad fan going its at 11. This cant be normal is it?

I am just about finished with the build. I have more than most people like to admit already tied into this build, and getting very frustrated when I cant trail with it. If anyone has any idea on what it could be you would be helping me more than you could imagine!

1983 351W
Mallory dist
msd super 2 coil
dual flow water pump

Keep in mind that I even ran the heater on the 75 degree day just to wheel, and she still overheated sitting still for 3-5 minutes........

Thanks.... Muddn7

 

[Broncobowsher]

Another victom of trying to cool a Bronco with an inadaquate electric fan.
Let me guess, some aftermarket low profile fan with 2000+CFM rating?
Very few electric fan can keep a Bronco cool. And the few that can have always been pullers. A good mechanical fan and fan shroud will do wonders. Staying cool on the highway is a sign that the radiator is a good size, the climbing tems is a sign that the forced cooling is not adaquate (highway shows ram air cooling is adaquate).

Now for the other issue. Dropping voltage. 11-12V is not good. Have the alternator checked. Probably have an issue and only putting out a fraction of the amps that it should.

 

[Viperwolf1]

Your battery voltage is low. Are you sure the alternator is working? Measure batt voltage with the engine off then again with engine running. It should be about 2 volts greater running. Could be the fan isn't getting enough current.

 

[Muddn7]

I guess I will take this lifetime warranty alternator back off and see whats up. I had a 302 that was well worn in the Bronco when I bought it, and never had an issue with the overheating. I mean none! The radiator is custom. By that, I mean it has been cut and welded for the 2wd steering box, and has a PS cooler mounted on the inside! I dont know how to get around the fact that room is limited to a shrouded fan.... I would hate to go to a different settup than what I have now with the radiator/ps cooler. I heard there might be a timing issue on early for v-8's that might cause a problem. The local parts store stated 10 like any other old ford, but my manual stats read under the hood. Sorry to inform but the sticker was probably lost 10 years ago from the vehicle I pulled the motor out of......

 

[Muddn7]

when I measure it with the motor off, thats fan, lights, and accessories off? Just want to get the full info on it. Then obvious same running, or will it even make a differance if I run it and test it in similiar configurations?

 

[Viperwolf1]

I'd try it both ways. With no load it'll tell you if your alternator is doing anything at all. With a full load it'll tell you if it can keep up with the electrical demand you have on it. Also check if engine speed makes any difference.

 

[jdcone]

The battery should read 12.5/.6 @ full. The altenator should be putting out 14.2V or more @ 2,000rpm. Have you checked your thermostat? The dual electric fan set-up from a Lincoln is suppose to work good in these things. Are you using a multimeter to check the voltage, or just the dash gauge? I just went through this crap last week. The 2 part places, both Kragens, told me the altenator was good. Carquest and my multimeter said otherwise.

 

[broncnaz]

X2 on the electric fan not being able to push enough air. Seems like most 4 core radiators are very hard to get air through with a mechanical fan much less a electric fan mounted in front further blocking flow.
I switched back to a 3 row radiator and my running hot issue went away.

I've never heard of any early ford V8 cooling problems.
If you used the 302 balancer your timing marks should be correct worst case there off 1-2 degrees due to maching tolerances but that shouldnt make you run hot.
Not sure what a dual flow water pump is but if its a high flow pump that can sometimes cause issues by flowing the water through the system to fast not allowing the water to cool off enough before it gets back to the engine.

While I dont think its a issue by the way you describe your problem you may want to get the cooling system pressure checked to ensure its holding pressure even a radiator cap that doesnt hold enough pressure can cause issues.

 

[SteveL]

I have 351w's in both of our broncos. I've had better luck with BC's standard 3 core than any of the 4 core radiator swaps. On the 72 I have been ok with a flex fan. On the 66 I had to swap to a fixed blade fan. I can feel the difference in HP but it stays plenty cool. If you get the cooling system right you won't need to worry about scoops and louvers.

 

[hdfx81]

you should always add antifreeze water alone will not keep it cool enough. Use a 50/50 mix of water and antifreeze and it will run alot cooler.

 

[blubuckaroo]

I don't know what you mean by "room is limited to a shrouded fan"? If you mean an electric shrouded fan, well, that, not going to be enough air. You're either going to have to make room for a good belt driven fan and shroud or install a big electric from a Taurus along with an alternator upgrade to drive it. The cooling on these things can be tough because of the lack of space and adding a bigger motor adds more heat load.

 

[wildbill]

;D ;D ;D My bronco has been running the 351W since 74 never a problem with heat. I run a 3 row stock rad. and stock fan. I would suggest you run a stock fan and try a 3 row good luck.;D ;D ;D Bill %) ;D

 

[Bitch'nBronco]

http://www.coldfire.biz/motormax/index.htm

My dad is a cold fire sales rep and this is similar to cold fire but its been formulated for motors. It supposedly will make a motor run much cooler, he got me a bottle of it for my bronco and will put in when I get to that point.

 

[Steve]

you should always add antifreeze water alone will not keep it cool enough. Use a 50/50 mix of water and antifreeze and it will run alot cooler.

That is not true at all.

Broncobowsher hit the nail on the head. You're not getting enough air through the radiator at low speeds.

 

[rhinobuggie]

When is the last time you soaked the rad. I use a kiddie swimming pool to soak mine once a year , help to get the dried dirt out . As for fans I have a stock 5 blade without a clutch and a electric as a pusher to help as needed
Jay

 

[HoosierDaddy]

Is the PS cooler part of the radiator ?

From all the reading I have done , isolating the radiator so that it is only cooling the motor load , seems to help a great deal. IE : Getting a seperate tranny cooler if you have an auto tranny , getting the PS fluid its own cooler if that is an issue , etc.
Some have added seperate engine oil coolers also , which seems to get a 5 to 10 degree drop in coolant temps.
My trail truck with a 351 (new rig - to me) just suffered the same fate as yours on its first trip out with me. I have not started working on it yet ....

 

[JKH67302]

Cooling Bronco

I have had trouble for years cooling my Bronco. My current set up is a 3-core radiator, flex fan and stock shroud. During a recent trail adventure I broke the fiberglass shroud. I just ordered a Ron Davis full circle shroud from Wild Horses and a fixed steel 18'' fan. I will get it all put on this weekend and we'll see how it works and let you know. The shroud was pricey, but I was very impressed with the quality and shrouding capabilities of this one compared to the stock one. More to come...

 

[av bronco]

I had the same problem with a 302 that never got close to getting hot to a stroked 351 I could not go 2 miles without hitting over 210 and would not stop climbing, after battling this for a year and a half I think im damm close to the total solution- see the swinging at the fences thread, also I have the inner fender cutouts, no diffrence and the cowel hood, no diffrence. The cheap e bay rad. did do a better job then the 4 core tho.