Cooling help?

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Iceman_krebs

Iceman_krebs

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Hey guys. I have a 1969 Dodge dart swinger with a 340 in it. I've been having cooling problems but I suspect that it is due to fact I don't have a shroud and thermostat. Any suggestions on a thermostat that would fit the neck of an air gap edelbrock intake #7576 and what temp to get? Also, I have a 15" flex fan (pic) and a 22" x 18" radiator. Any ideas what fan shroud I should get or how to go about finding one? I've tried the google searching. Should I stick w the flex fan or get another one? Any help would be greatly appreciated. Thank you.

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That's funny, the Iceman needs cooling help. But seriously folks, I haven't heard much good about flex fans. My understanding is you are better off getting a stock style clutch fan. I can't help you with a part number for a shroud, but I did see somewhere an article on making a decent looking fiberglass one, I'll see if I can find it and a link.
Fan Shroud Fabrication - Street Rodder Magazine
 
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definitely a fan shroud with the fan sticking half in the fan shroud to take full advantage of the rad air flow. You could use a 180 or 195 thermostat, either will work. As for the 15 inch flex fan I would ditch it and go with a 18 inch Mopar OEM fan 2863224 it will pull more air through the rad.
 
I had a cooling issue as well with my 68 340. Using stock fan and clutch. I went with a 4 core rad, shroud and high flow 180 therm from classic industries. I also added a high flow water pump from Summit. The water pump did not have the normal high flow impeller like you would see on a 340 with AC. It has an impeller like you would see on hydronics system pump in a building if you know what i am talking about. Here is the link FlowKooler Hi Flow Mechanical Water Pumps 1701. Motor runs cool. Oh and car has AC. Nice last name!
 
Before you buy anything else, ditch that fan!

Then we need to know when is it not cooling; is it at idle? or speeds under 30mph? or from 30 to cruising speed? Each of these has different solutions
 
Like others have said. Ditch the flex fan and get a viscous clutch fan and a shroud. You shouldn't run without a thermostat as it could cause damage. Not running hot enough. Of course you don't have that problem. Assuming your water pump is in good shape and your radiator isn't clogged with crap. I would think you would be in good shape after a decent fan upgrade. I don't use a shroud, but I have one in case I have cooling problems.
 
7 blade non flex, add shroud, clutch is good, but they fail at the weirdest times.
I once changed a water pump on a small block, and it had lost about half its blades.
That made a big difference.
 
FWIW.

I have several vehicles successfully running around with 7 blade viscous fans, NO shroud.

Can you get a measurement from the fan mount flange to the rad. It's gonna be close, but a OEM 69 clutch fan is 2 5/8 inches from flange to end of clutch, 3 1/2" for a moho 7 blade clutch that I commonly use..

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hope it helps . cheers

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and Yep, the fan clearance is only about a 1/4 inch from the clutch to the rad, the motor is secured from moving forward in case of abrupt stops.

After 4 yrs of spirited driving by my son,, no interference yet.. lol

I'm touching wood here.. lol
 
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inertia said:
FWIW.

I have several vehicles successfully running around with 7 blade viscous fans, NO shroud.

Can you get a measurement from the fan mount flange to the rad. It's gonna be close, but a OEM 69 clutch fan is 2 5/8 inches from flange to end of clutch, 3 1/2" for a moho 7 blade clutch that I commonly use..

View attachment 1714943336

View attachment 1714943338

hope it helps . cheers

View attachment 1714943340

and Yep, the fan clearance is only about a 1/4 inch from the clutch to the rad, the motor is secured from moving forward in case of abrupt stops.

After 4 yrs of spirited driving by my son,, no interference yet.. lol

I'm touching wood here.. lol
Click to expand...

Quarter inch is scary!, but should pull air through like crazy, without a shroud.
 
Darthomas said:
Quarter inch is scary!, but should pull air through like crazy, without a shroud.
Click to expand...

I was a little worried when I put it in, But since then I've used 2 other similar units from motorhome's, cheap at $30, no interference from any, it's closest by the upper tank, did a little adjusticating there.

cheers.
 
Thank you so much for all the info guys. I greatly appreciate it. I've got a 180 thermostat on order and I'm gonna fifth the flex fan for an 18" clutch fan. The water pump and 2 stage radiator are brand new, but I guess that doesn't mean I could have a blockage. I'll throw the new fan and thermostat in and see what happens and then if I need the shroud I'll put that in too.

Definitely starts over heating while at idle to 30 mph. Any other info or advice is welcomed and appreciated. The iceman needs to stay cool!
 
Problems from Idle to 30mph point to not enough air-flow through the rad.This usually points to the fan. But can include the shroud, a faulty fan-clutch,and airflow to,through,and around, the rad and also out from underneath the hood.
The stat sets the minimum running temperature. If/when over-cooling is possible,the stat will close, to try to keep the engine at a minimum running temperature.
Good cooling from cruising speed, down to about 30mph, indicates that the system is able to shed heat with ram-air flow through the rad, and adequate coolant circulation.
 
Got it running cool now fellas. Thanks for the ideas. Went w a derale single electric fan and shroud combo. Put some low profile bolts on for the water pump pulley. I have 3/4" to spare. Also went w the derale single fan controller. Don't recommend this though. The temperature sensor in the radiator works intermittently at best, so I use the manual switch most of the time.

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Yeah that WP pulley looks to be mighty small, which means that if the lower is still original size, That WP is gonna be slamming the water through at a higher speed than Might be required.And if it gets to moving too fast,it may not pick up the heat. Or it may cavitate and destroy the pump. And you may not realize that has happened, cuz the only evidence is the rapidly climbing temp.gauge.
But if the lower pulley is properly sized to maintain the factory ratio, then you're good.
Manually operating the fan-controller is not a good idea. It is ok to have a manual over-ride, but the automatic mode should remain operational.Running the engine too cool is not a good thing either. Not good for power,or economy,nor engine life.
 
Just looking at the 2nd pix in the 2nd pix group, the crank pulley looks to be smaller than the WP pulley......it is almost totally hidden by the WP pulley but you can see it.
 
nm9stheham said:
Just looking at the 2nd pix in the 2nd pix group, the crank pulley looks to be smaller than the WP pulley......it is almost totally hidden by the WP pulley but you can see it.
Click to expand...
Yep, most the aftermarket pulleys are all under driven, in fact I have yet to see any sold for mopars that are over driven, it is the exact opposite of what you want when you have cooling issues. If you have an aftermarket aluminum rad with 2 cores, like a lot of them are, the core tubes are larger and you need more flow to get the coolant to tumble through them and shed heat.
 
Here's a new car we fired last thursday. It was a 93* record breaking day.

The car is 340, with a new Champion rad, and thats a 5 blade clutch fan.

It ran all thru break-in, thru tune-up, then the nec test drives, 180 thermostat, and never moved past 185 ish.

No shroud, seals, electric fans.

hope it helps, cheers

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The water pump pulley is smaller than the crank pulley. I don't kick the fan on until it hits 180. Doesn't go above 190 usually.
 
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