The "pancake" fan is what I'm running now, a 16" one. I figured I would get better results with a shrouded fan. But I don't know, maybe I'm running as cool as can be expected in this weather...
Are you running an aluminum radiator? Makes all the difference in the world with a modified V8... I had hot problems for years, and messed with thermostats, cooling fans, antifreeze percentages, etc, but when I swapped to a thicker aluminum radiator, I found that I had to back off on the fan usage or it would run too COOL!!! In south Texas... If the fan ran all the time, it would run 160-170, so I put in a thermostatic switch and it now runs right at 180-190, then kicks off.
That's what's puzzling me. I run just under 200 on the highway, and about 210 or more in traffic. Granted it's been upper 90's outside lately, humid, and there's the radiant heat from the asphalt - it's been terribly hot these past couple of weeks. But I have a big, thick aluminum radiator, looks just like yours or Bryant's. My fan's also on a thermostatic switch. My water pump is new, thermostat is good, running about 70/30 water to antifreeze and a bottle of "WaterWetter" too. I've rigged my fan as a puller, reversed it as a pusher, still no luck in this heat. My carb is well tuned, timing is right, runs great otherwise. So I think either my fan's inadequate, or maybe there's too much electrical load on my stock type alternator for the fan to run optimally. I do have a stereo with an amp, MSD box, halogen headlights... At idle, my ammeter sometimes goes into the negative with all of that on and the fan running. So maybe I need to get a higher amp alternator?
Where is your temperature sensor located...just wondering out loud if you are picking up a false hot reading or reading at a hotter area in your cooling system... I used to run one that had a long line that had to be routed over the top of the engine toward the "cockpit", and I thought I was running hot, but it was picking up heat from sitting on top of the head it was sitting on. I lifted it and put it on top of the valve cover bolts, and it cooled down about 20 degrees. On the highway, it doesn't matter what fan you are running because the 70 mph air being forced into the radiator is more than any fan can push/pull. What temp thermostat are you running? High flow stat? Just tossing out brainstorming questions, because you shouldn't have a problem keeping cool with your setup. (by the way, I never read your entire signature description of your engine until just now...)
I will try that. I'm running a mechanical gauge, sender is toward the front of the intake manifold and the line to it does go over the top of the engine. I hope that fixes it, but I do think the heat problem is real because if I shut if off after being in traffic and don't get some wind on it, the gauge will climb sometimes as high as 230 and when that happens the starter strains to crank it. At normal temp I can bump the starter just once and it fires right up. Thermostat is a Fail-Safe 160 with a couple of holes drilled in it. (I know, I know - Fail-Safe thermostats are the devil, but it was the only 160 they had in stock and I got really paranoid after my regular 180 'stat locked shut on me. First time I'd ever seen that happen.) That's why this is serious business! Do you have any idea what this kind of heat can do to a lateral spark plenum? Especially with a port job. It'll eat right through the hydraulic fluid jacket and blow us all to hell!
Switch to a 180 degree thermostat. It will slow the coolant flow which gives it more time in the radiator. It may not change your temp but it is a cheap alternative.
Well I figured it out. Not the thermostat. Not the water pump, heater core, radiator cap, timing, carb, or fan. Although I have legitimately had to fix all of those in the past six months or so. No, it's better than that. I went back to the junkyard today and got an Escort fan, (thanks, Bryant!) I did make it fit. I checked my coolant level and it was low again. Typical. I figured it puked out again due to the heat. I touch off the wires to make sure the can spins freely before I wire it up, and WHOOSH! I get a huge misty cloud of coolant in my face. Yep! I have a hole about halfway up my radiator. I guess it is (was) a hell of a good radiator to have kept it as cool as it did. But no more... Guess I'll probably get another one of those (~$200 From Jeg's) unless anybody has a better suggestion.
Glad you found your problem. It just didn't seem to jive that you had that good of a setup and were running hot. There has been a thread on here lately a couple times, where someone is selling direct fit aluminum radiators.
Here it is... 8 left as of July 12. $240 +$25 shipping http://mmb.maverick.to/showthread.php?t=45697&highlight=aluminum+radiator+fit
Yeah, but I hadn't noticed since my overflow tank is black and opaque. I might get something else next time I go to Pull-A-Part. I just love an excuse to go there. Weather permitting, of course. I found the hole easy enough, and I soldered it. Maybe it will hold, we'll see...
