A couple of photos from my "another cheap electric fan build"

[kevmic28]

How were you able to remove the threaded bolt in the head. I have been trying to get mine out and its not budging. Even with a cheater bar it didnt even budge. I tried using a propane torch to heat it up a couple times but no dice. Im going to head into town and get some pb blaster, let it soak over night and try again in the morning.

[Old Yeller 1970]

My OEM heads are sitting on the shop floor. I put the plugs in myself when I built the engine because I have a set of Pro Lightening heads on my rig. But I think I'll go look at my old 441s and see what the plugs look like and report back.

EDIT: The plug is missing out of my head. When I pulled the heads off the engine I must have salvaged the plug for use elsewhere. It must have come out easy enough or I wouldn't have fooled with it.

[kevmic28]

The plug (between 6 and 8) has a 3/8 square female socket. With the engine out of the truck it would be so much easier to remove this plug, right now I am dealing with working around the headers, fenders and ac cables.

[Classic Heartbeat]

Well, Jegs said to put it in the engine (the right head in my case). I think that's logical because that's were the thermostat is and also the sending unit for the water temp gauge on the dash. Since the water heats up there sooner than the radiator, I'd want the radiator fan to turn on and start cooling the water as soon as the engine reached the thermostat's operating temperature. That way cooler water immediately starts to keep the engine cool. Maybe putting the sensor in the radiator would work but I don't see an easy way to mount it.

There is a problem not considered here. Once the hot water flushes from the engine, it is replaced with cooled water from the radiator. The cooled water flushes from the radiator into the engine, reaching the temperature probe in the head (almost immediately) and the fan shuts off. Now you have a radiator full of hot water, the fan will have shut off and won't come back on until the water in the engine reaches temperature again. Then the cycle starts all over, only now the water in the radiator is hot because the fan didn't have sufficient time to cool it. See what I am talking about.
Both Flex-A-Lite and Deraily sell thermostats that either go directly into the water through the top nozzle in the radiator or slip into the cooling fins in the top of the radiator core itself. WES

[mustardjimmy71]

^x2
ive used the adjustable with the sensing bulb that goes in the fins several times with good success. make sure you use a relay and put the sensing bulb low in the rad so if you run low on fluid the fan comes on.

[Old Yeller 1970]

Wes, I see your point. But if it was working exactly like you say wouldn't the temperature gauge on the dash swing up and down as the hot cold water entered/exited the engine? My gauge comes up to operating temperature and stays in one position. I don't know what the open/close range is on the units you mentioned. The Jegs sensor closes at 185 degrees and stays closed till the temp drops to 170. I would think that at that point the fan is going to be kept on till the engine is shut off. Maybe the other method is better but so far the Jegs kit appears to be working fine. Unfortunately I won't be driving it for awhile to keep testing it out. My PS gear box just gave out. Don't you have those variable ratio gear boxes?

EDIT: I found the gear box.

[68GMCCustom]

my "Old Air Products" dual e-fan setup thats made for these trucks uses a probe inserted into the rad fins to monitor the temp. With a stock LSx thermostat (195?) my gauge sits in the 180-185 range once it warms up. Haven't seen it higher except for when I was 1st filling up the system. Mine's setup for the low speed fan to run when the keys on, and the high speed only comes in when and as needed (as set on the thermostat) then shuts back off.

[mustardjimmy71]

another disadvantage of the one in the side of the motor is it usualy needs to be removed to remove exhaust manifolds

[Classic Heartbeat]

Wes, I see your point. But if it was working exactly like you say wouldn't the temperature gauge on the dash swing up and down as the hot cold water entered/exited the engine? My gauge comes up to operating temperature and stays in one position. I don't know what the open/close range is on the units you mentioned. The Jegs sensor closes at 185 degrees and stays closed till the temp drops to 170. I would think that at that point the fan is going to be kept on till the engine is shut off. Maybe the other method is better but so far the Jegs kit appears to be working fine. Unfortunately I won't be driving it for awhile to keep testing it out. My PS gear box just gave out. Don't you have those variable ratio gear boxes?

I stopped selling the variable ratio steering gears because the turning radius was slightly less. We still sell the "RedHead" quick ratio and have had great reviews with them. Our customers (several of witch are board members) love them. I have a couple in stock.
To speak to the thermostat issue, they are all basicly the same temprature range wise. However they are adjustible as to what temprature you want them to turn the fan on at.
To speak to the fluxuating temp gauge, yes the gauge will move some because you are cooling the engine some when the water moves, but that is what is supposed to happen. You do not ever maintain one even temprature. After all the hot water opens the thermostat that allows your water to exchange, and the cool water closes it.
The real test to a cooling systom is not while driving down the road where you have ambiant air forced through the radiator witch asists in cooling, but just sitting in traffic idleing. Then the fans have to do all the work. That is where the temprature sensor in the head will be innefective. WES

[Old Yeller 1970]

Originally Posted by Classic Heartbeat

The real test to a cooling systom is not while driving down the road where you have ambiant air forced through the radiator witch asists in cooling, but just sitting in traffic idleing. Then the fans have to do all the work. That is where the temprature sensor in the head will be innefective. WES

I'll keep on eye on it. As soon as I'm able to drive the truck again, I'll let it warm up and see what's happening (fan either running or not) while it's idling on a hot day.

[kevmic28]

I have not been able to remove that plug, can I just wire it up to the temp sender unit?

[Old Yeller 1970]

That won't work. The temp sending unit operates under completely different principles. The only two options I can think of are to put it in the intake manifold if yours is aftermarket and has an extra port (Edelbrock Performer for example) or get the kind of sensor that goes on the fins of the radiator like WES was talking about.

[kevmic28]

Ok, what about a water outlet neck that has a sensor port in it? Like this one
http://www.oreillyauto.com/site/c/detail/MUR0/84842.oap
I have just about rounded off the plug trying to get it out. Tried, heat cycles and pb blaster but no dice. If this wont work Ill probably just end up taking it to a shop and having them pull it.

[Old Yeller 1970]

I bet the sensor port would work. That's a lot cheaper than pulling off the head and having it worked on. As long as the fans come on once the engine warms up that's what really matters. Since it will be right next to the thermostat that shouldn't be a problem, IMO. If the sensor port doesn't work you're only out a few bucks anyway.

[kevmic28]

ok sounds good. Ill pick one up tomorrow and throw my system together. I have been having issues with running hot in town, hopefully this will solve those issues.

[Old Yeller 1970]

Originally Posted by kevmic28

I have been having issues with running hot in town, hopefully this will solve those issues.

If you still have the original copper radiator and haven't had it rodded out in a long time you may want to do that too while your working on it.

[kevmic28]

Its a new 4 core radiator, new heater core with the Vintage air and new water pump. Since I am gonna take the thermostat cap off to replace I will go ahead and replace the thermostat while I am in there.

[Old Yeller 1970]

I'm about to head out of town on business so I won't be able to respond till tomorrow but its my understanding that if you have a closed system cap on it without a recovery tank you may be getting air in the system and causing your trouble that way. Right now I have the same issue (closed system cap with no tank - the tank closes the system). I'm waiting on the back ordered tank from Jegs to see if this resolves the issue for me too.

[kevmic28]

I have a tank. I have been wondering if its a bad temp sensor too.

[kevmic28]

Ok I got mine installed today. My temp gage still goes way to high, it must me a bad sensor or the wrong one for my truck. At any rate Ill replace that tomorrow but as far as the fan kit goes it works just fine. I had to replace the circuit breaker that came with the jegs kit. It would shut off after 20 seconds so the fan was constantly shutting off. I tried wiring it with my ac so it would come on as soon as the ac turned on but it would blow the circuit breaker if I turned the ac above low so I wired in a toggle switch to the cab so i can turn the fan on with the ac. I found a wiring kit that works with the ac so I may pick it up this week and try it out. Here is the part number if any one wants it.
TorqFlo part# 733647
The suction through the radiator at idle is enough to suck the bugs up to the radiator. So I will have to make sure I keep the radiator clean.
Anyone have the correct temp sender part number for our trucks? I want to pick up a new one tomorrow at autozone/ Advanced/ or Oreileys tomorrow?

[Wooderson]

Hey guys! New to this board and already found tons of great info. Quick question - I have a 1970 with a basic 350. Can I run this fan with my stock alternator (63amp - I think?) or do I need to upgrade the alt? Thanks.

[kevmic28]

Im runnig it with the stock alternator. Check the Faqs sections for a complete run down of this install.

[68GMCCustom]

I would think you'd run into a problem with fans running, headlights on, stereo, turn signal, maybe the wipers too or heat/ac.....all while sitting at an intersection idling.
I upgraded from a 63amp to a 93amp when I added my e-fans and the new alternator handled everything fine.

with the new LSx it has a 140amp now.

[kevmic28]

When I have the extra cash I will upgrade to a better alt. But right now the truck doesnt get driven much. Im usually on my Harley. Much cheaper on the gas... But then again I dont know if the alt has already been upgraded already. How can I tell?

[Old Yeller 1970]

I'm still running my stock alternator. Someone in the build thread said these fans don't pull a lot of amps so I"m not too worried about it. I'm also sans A/C.