Hello everyone, I need some serious help. I have a 78 bronco with a 351M, new 2 row alumminum radiator, new hoses, new OEM replacement water pump, stant 180 degree T-stat, OEM clutch fan setup, and in the Phoenix, Arizona heat I have an over heating problem. Does anyone have any suggestions to what I can do to get it to stay cool. I would appreciate any help.

P.S. I put the T-stat in it the other day and I believe I have gotten all of the air pockets out of it. I'm going to try to rebleed it but I'm just wondering if anyone has any suggestions. Thanks

Mike

well i put a 4 core copper radiator and duel electric fans in mine works great
dont have to fans on while on the highway and you get alittle more hp

Mike,
On an emergency basis, one can get a little extra cooling buy turning on the heat.
I'm not suggesting that as a long term solution by any means.
But it may help you get home when you need to.
joe

Test your new t-stat by putting it in water on a stove along with a thermometer. when the spring collapses see what temp you have. i do that to all of my new t-stats and found that you run across quite a few bad ones.

Thats the way I've been driving it around here, with the heat on but the 100+ degree weather in AZ. plus the heat on.. just bad news right there.. What size electric fans are you running? I actually had the overheating problem without he thermostat, so I thought if I put one in it would cool the anti-freeze off a little bit because of it sitting in the radiator a little longer but I was wrong..

Are you going off of a gauge or is the radiator actually burping coolant? If it is spewing out of the radiator then maybe try a new radiator cap?? Pressure spring may be tired in the cap. I am also in Phoenix if you want to try using my cap tester. Not thats its very expensive to buy a new cap but it will tell you if it is possibly the problem. I am also going to part out my 78 XLT Ranger so if you need some parts....

Good questions!

Can the clutches in the fan go bad?
IF so... could bad clutches allow the fan to turn too slowly?
I understand that they are to allow the fan to turn faster than the engine (when at highway speeds) so I am thinking that they should allow slippage in only ONE direction, but I don't know.

The radiator cap is brand new. It doesn't leak any anti-freeze unless I take the cap off and start it and let it run that way. I found out today driving to school that if I go between 65-70mph. the temp gauge will read between 210 and a little higher, but if I go between 50-55mph it will read at 210 which I don't understand. When I was bleeding it, it would actually blow some good bubbles, but they all seem to go away. and parts I'll always need parts. I'm particularly in need of a gear box, and round headlight bezels, but if that is an xlt that comes with square headlights right??
I'm not sure about the clutch fan, I was always told if you can spin the fan without the clutch spinning it was okay, and if you couldn't spin the fan without the clutch it was bad and to replace it. I'm not sure on that either. I'm going to do a little searching for it. Just to make sure, if you have a 180 T-stat it should run somewhere around there correct? And I've looked, but not hard. Does anyone know the temp these 351M engines at?

im runnin the fans out of taurus and do you have a fan shroud if not you will run hot sitting in traffic

I do have a fan shroud on the truck

Does it make any difference of the fact that it is bored .30 over?

The fan clutch actually free wheels all the time. When the engine is running warm the fan clutch will firm up and free wheel less actually becoming closer to a direct drive. A thermostatic fan clutch is the only way to go in hot weather. They are expensive but they have solved my over heating problems more than once. A dead giveaway that your fan clutch is not working is when the engine is at operating temperature, have someone shut off the engine and the fan should stop spinning within approximately 1-2 turns. If it spins freely then your clutch is not cooling your radiator. At freeway speeds the fan clutch should be a little looser so that there is not so much drag on the motor. Have you ever heard those people driving down the road with the a/c on and it sounds like the fan is pulling them down the road? I have read that the 351/400 engines usually run hot but mine does not. I upgraded my 351M to have a sanden air compressor so the a/c is more efficient than the york compressor. Are you running a/c?

Where would I go to find a thermostatic fan clutch, because I'm willing to do anything to get this thing cool. I do have A/C and would like to use it, but can't.... It is the factory unit and I do need to replace it soon because its noisy, and I can't remove it from the engine, for some reason when I take out the one bolt on top of the compressor freon starts coming out. So eventually I will need to get another one of those, but cooling is the first thing I need to take care of, then the steering... The steering has excessive play in it and it all leads back to the gearbox..

Any parts store will have one. A thermostatic fan clutch has a coil like a choke thermostat on the front of it. When the fan clutch coil starts to warm up it starts to release the fluid inside the fan clutch which makes the fan spin freely as it warms. The warmer it gets the more fluid it releases the easier the clutch spins.

Thanks for the help, when I get back from New Jersey I will go pick one up and hope and prey it helps with my cooling problem..

well I got back from jersey and bought a clutch. The guy at the 4x4 place in jersey said to try an additive called 40below its made by prolong, and between the 2 it seems to have cooled off about 15 degrees or so, and runs great at night and during the cooler days of Phoenix, but on the nice and hot days it starts to climb again. So I'm almost back to square one again, but made a little progress.. if anyone has anymore suggestions let me know please.. thanks


Mike

Mike,
I did a quick search for auxillary cooler at JCWhitney
http://www.jcwhitney.com/autoparts/Product...uxillary+cooler

I'm not suggestiong that is the way to go, just an option.