ELECTRIC vs FLEX FAN ????

[Vegas T]

I need help from you guys, I currently have a 350 crate engine with a flex fan. Not sure how many cores the radiator is but I just changed the coolant and the car help exactly 2 gallons. I'm in Vegas so the temps are extreme out here. I installed a 180 stat and on an 85/90 degree day she runs at about 190 to 195 (if the autometer gauge is correct) and if I sit for about 5 minutes in traffic she will climb to 210 to 220. I have heard an electric fan will do more good than a flex fan, can anyone confirm this before I go through the process of the swap only to find I am back where I started. Thanks for the help, I am a new guy to the board but can't believe how helpful everyone here is. I plan to be here a while.
Buck

 

[bill4u6]

i use a electric fan wired with a relay and controled with a thermo switch in the head. i have a mild built 350,a mustang 3 row rad.i have been in some stop and go trafic with the temp at 90 + and it ran 195 to 180 the electric fan so far does a good job

 

[tfeverfred]

My flex fan cools mine good, but the engine is stock and the radiator is rated for 650HP. I have never been over 180 degrees, even in traffic. She cruises at 140 - 160 degrees.

 

[Vegas T]

I get the feeling my radiator is not anything special, just your average 17"x21" standard T unit. Again, any input is helpful on this...

 

[bill4u6]

i like my engine to run at least 170 and above but not over 195 i think these temps are more efficient for a engine

 

[VegasBruce]

Buck,
I'm running a flex fan on mine. I won't run an electric if I can get out of it, just doesn't look right to me.
At Henderson days in April I had a problem with running hot, up over 220 when sitting in traffic. Afterwards I drained out the coolent, including the block drains to get it all out. Replaced it with water and a bottle of Water Wetter from Redline. I didn't have any problems in Bolder City last month. I still feel the need for a fan shroud, i just need time to build it.
I hope this helps.

 

[Vegas T]

Bruce,
When I drained and filled with the 50/50 dextron mix I added water wetter hoping this would help. I was hoping changing from green to orange coolant would help. I really have nothing to compare the new coolant to as I just aquired the car a few weeks ago. I did have a guy tell me today at Freemont Street the electric fan will make it run cooler but I'm not sure about that...

 

[Duke]

I am surprised that yours only holds 2 gallons, mine holds 3 1/2 gallons. I have a 350 Vortex Crate engine in mine. I would make sure you haven't any air pockets in the system. You may have to drain and fill slowly. Make sure your thermostat has a small bleed hole and it isn't plugged, You can turn the thermostat upside down and hold up to the light, there usally is a little dimple inside you can see light thru, less than 1/8". That is the thermostat bypass, it lets air bleed while filling the system. Another thing, make sure the radiator is large enough for a 350, an electric or flex fan should do job. OH, one other thing, make sure the fan is installed for the right rotation ( sucks instead of blows ) I have seen flex fans put on backwards.

 

[VegasBruce]

Bruce,
When I drained and filled with the 50/50 dextron mix I added water wetter hoping this would help. I was hoping changing from green to orange coolant would help. I really have nothing to compare the new coolant to as I just aquired the car a few weeks ago. I did have a guy tell me today at Freemont Street the electric fan will make it run cooler but I'm not sure about that...

I left the coolent out, just used the water wetter. The electric fan will help it run cooler in traffic. It speeds up the airflow thru the radiator when your not moving. Oh, I forgot earlier I gutted the thermostat, cut it apart and just used the outer housing for a flow restrictor. A t-stat is not needed here in the desert, but you do need a flow restrictor.

Do you have your car on Fremont Street this weekend. I waited to long and didn't get a spot.

 

[donsrods]

This is one subject that has people lined up on both sides of the argument......some like engine driven fans and some like electric fans. I live in Florida and use only electric fans on our cars because at idle an engine driven fan is running at it's slowest, exactly when you need the most amount of air flow. An electric fan runs at much higher rpms and therefore IMO provides much better cooling when sitting at a light.

I also use a fan shroud and a 16 inch puller fan. I prefer SPAL fans because I have had such good luck with them. My T runs down the road at 150-160 and at a light may come up to 180, but as soon as the fan is turned on it drops to 150 again. I am going to bump up from a 160 thermostat to a 180 to get the engine to warm up somewhat.

I can't stress the importance of a fan shroud enough. Just tacking the electric fan to the bare radiator only pulls in a certain amount of air, the shroud lets it catch the entire surface of the radiator.

I also prefer aluminum radiators, but again, that is a hotly discussed subject.

Don

 

[Shawn F.]

Do you run a shroud? I'd try to get it running at about 180 constant. You do not want a engine to run TOO cool either. Most people think that the cooler the better but that is not the case and we all here can probably go into why, how, what happens to metal when it's hot and cold, expanding, yada yada...
Anyways check for air pockets. Take all fluid out, fill it up slow, park on a hill and let it run with cap off for a bit. Another thing you can do is drill a small hole in the thermostat (I guess someone said they already have this hole but I didn't see one on some of them) which will let the air pocket out. Shroud is a big part of it though, if you do not have one, get one and I bet that will solve most of the problem right there. That water wetter stuff I hear will bring temps down a whole 10 degrees too. As for electric vs flex fan, I hear a lot of people argue back and forth. As for what is correct I don't know, I'm just some dumb 20 year old kid that messes with hot rods. I run flex fans on my old cars and they do just fine. I've put electric fans on a few hot rods (one 57 Chevy comes to mind) that would not stay cool enough with a flex fan so on went an electric fan with a thermo switch ran in line with a relay and it did the trick.
If I remember correct or was told correct, you want an engine to run at 180-190 no less no more. Please correct me if I am wrong, I don't like to give out false info.

 

[tfeverfred]

"If I remember correct or was told correct, you want an engine to run at 180-190 no less no more. Please correct me if I am wrong, I don't like to give out false info."

I have heard this too. I have noticed that my car seems to run better when it gets in traffic and heats up, but the difference is minimal. Or so it seems. What would be some of the bad things, if it runs lower than 180 degrees?

 

[Vegas T]

I am running a shroud, and though about air pockets, on the re-fill, I put in what I could and them warmed the engine up until the stat opened. Then I let it cool, thinking any air would collect in the radiator since it's the highest point. This is when I was able to squeeze in the rest of the 2 gallons. Forgot to mention when I drained it I had a greese like substance on the inside of the radiator cap. At first I freeked, thinking I had oil in my coolant, however, after consulting 2 different mechanics I know they both feel it was block seal which I guess some builders use on a new engine. When I opened the cap today I did find some more of the substance but reolized I never flushed the aluminum overflow. When I opened it up it had some residue in it and that is probably where the second batch came from. Again, I thought running the engine and then letting it cool would bring air to the radiator and it did. When I open the cap not the coolant is about 3/4" from the top of the radiator. Any thoughts?

 

[Shawn F.]

One of the reasons is because an engine is built to certain specs and things are tightened to certain specs, etc. When metal heats it expands. Piston, rods, etc etc. Takes up that space that was left (can't think of the name you would call it right now). See what I mean? Plus another one has to do with fuel, spark, etc but has too much math for me to explain. I understand it in my head but can't explain it in words. I was never any good at math.

 

[Brucer]

hello.. its the argumentive guy...



if your running a flex fan and want to keep it.. i have an option.. might work, might not, but its worth a shot...

try a truck oil filter and an oil cooler, if i were in vegas i would have them anyways... a fram hp373 i think thats the part number, it should be about a 1 1/2 quart oil filter, you might have to order it.. its an extra capacity oil filer for industrial trucks and the like... a $50 oil cooler and your good to go.. believe it will drop your temps down a bit


i have a big block, running 11:1 compression, standard 3 core radiator, an oil cooler and a tranny cooler and can do 100 degree summer days in western kentucky...


and with that, do you have a tranny cooler? you can add a tranny cooler, and that will allow your radiator to cool your engine more effeciently..might look into seperate tranny unit with a fan on it with a stand alomne fan on it, b&m sells a nice compact unit with a fan an sending unit on it..

its all about total system cooling than it is just one paticular unit.. just something to think of.. outside the box anyways..

 

[RPM]

Just some food for thought on engine temps. All of the stock factory cars I have ever worked on had a 195 thermostat in them from the factory. The factory cars with electric fans, have that fan come on at 230. So this tells me they want these engine to run between 195 and 230.

 

[Rick]

Thats where NASCAR runs um.

 

[GT63]

Just some food for thought on engine temps. All of the stock factory cars I have ever worked on had a 195 thermostat in them from the factory. The factory cars with electric fans, have that fan come on at 230. So this tells me they want these engine to run between 195 and 230.

My 2008 Silverado runs right at 210 all the time.

 

[Vegas T]

Bruce,
I didn't have a car in the show, just found out about it saturday morning. There is a Meet and Great on camino al nonte at North Star Bar N Grill I am going to make on June 28th, starts at 4pm. They had flyers at the shop yesterday.

 

[LumenAl]

I had a Welbaum Brass radiator that was custom built back in the early 70's as confirmed by Bill Isley prior to his passing... in the original setup it worked OK... leaked, but got that repaired. Upon rebuilding the engine, adding the tunnel ram and 2-4 barrel carbs onto this high compression engine, it simply no longer kept it cool... any delay in traffic became a major problem... I also emptied the system, ran pure water and a water wetter additive, but only helped slightly. The down side to this approach is the coolant also acts as a lubricant for your water pump and running without any will take a toll on your water pump.

I then had Bill build me a new Brass Radiator that was 2 each 2 inch cores that sandwiched a electric fan inside... it works great!, but still looks old school as you can't see it... Price? lets just say well over a $1,000 and it took me a long time to make that decision, but once I did, I was very pleased with the results...

So clearly, a well designed radiator with an electric fan is your best protection against over heating, but a larger capacity radiator with a coolant recovery system can also work with a flex-fan... so my take is, if you're over heating and using a flex fan... better get yourself an electric fan as they do a much better job of providing airflow when you need it the most... traffic conditions and parade pace cruising...