Cooling problems

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zigs

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I have a 68 dart with a 470 . I'm in the process of getting it on the street . When I switched over from the 354 I left the 22" radiator in , it was fairly new . I had been using it with the 470
idling in the garage and about a two mile test trip. This week end I dropped the tranny pan and replaced it with an aluminum pan with plug. I put fresh fluid back in and let idle, I ran it in neutral and through the gears. I decided to take it out and check it out , same run as I had done before . By the time I got back the radiator was boiling over. It was over 90 degrees here. I wouldn't think the transmission would have something to do with that ? or coincidence.
Maybe should think about bigger radiator? Any ideas?
 
Take pics of your fan, radiator setup. Also, when is it getting hot, idle or on the road at let's say, a constant 45mph+?

I assume you are running coolant and not just straight water.
 
Take pics of your fan, radiator setup. Also, when is it getting hot, idle or on the road at let's say, a constant 45mph+?

I assume you are running coolant and not just straight water.
Idling it was pushing 200 . I was doing about 40 . Radiator is 22" with 16" electric fan with shroud and using coolant
 
Over 40ish mph is a cooling system problem, assuming adequate ignition timing.
By this speed ram air should have taken over. The shroud and fan are by now out of the picture, and the stat should be running wide open.
So you need to look to the basics;adequate rad exposure to the wind,adequate waterpump rpm, and rad efficiency.
Of course it wouldn't hurt to verify the stat is opening WIDE.
There should be,at 40 mph, a 30 to 50 degree difference in the cooling system temp between the top of the rad and the bottom. Straight water is a better coolant that any ratio of antifreeze. To run it tho, you have to protect the water-pump seal with an additive-package.
Adequate waterpump rpm starts with your engine rpm at the overheat speed. And Adequate engine timing usually includes the VA system. Most SBMopes like 44 to 54 degrees at about 2200 rpm when cruising. I have no idea about 470's but I can't imagine they would be much different.
 
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I was speaking to a rad guy last week about recoring my rad and my "high" temps (190ish). $600 for recore...lol
Anyway a trick he uses to check for plugged rad is to drain it, then fill the rad up from the BOTTOM. Once its filled, pull "the plug" so to speak.
If it takes longer than 3-5 seconds to drain, its partially plugged.
For each "extra" second it takes to drain accounts for 10% blockage.
 
600$ recore ? You can get custom radiator made for less.
 
Over 40ish mph is a cooling system problem, assuming adequate ignition timing.
By this speed ram air should have taken over. The shroud and fan are by now out of the picture, and the stat should be running wide open.
So you need to look to the basics;adequate rad exposure to the wind,adequate waterpump rpm, and rad efficiency.
Of course it wouldn't hurt to verify the stat is opening WIDE.
There should be,at 40 mph, a 30 to 50 degree difference in the cooling system temp between the top of the rad and the bottom. Straight water is a better coolant that any ratio of antifreeze. To run it tho, you have to protect the water-pump seal with an additive-package.
Adequate waterpump rpm starts with your engine rpm at the overheat speed. And Adequate engine timing usually includes the VA system. Most SBMopes like 44 to 54 degrees at about 2200 rpm when cruising. I have no idea about 470's but I can't imagine they would be much different.

Tonight when I got home I started with the basics. I pulled the pump belt and made sure the pump spun , Its oem passenger side inlet , spun free . Next since there was no water left I filled the radiator and pulled the drain plug , dumped easy no problem . then I pulled the thermostat put the neck back together filled with water only.
I started it and let it run for about 20 min in park then neutral , drive etc . temp stayed good for about 10 min , between 15o and 180 then the last ten min moved up slowly to 200. I shut it down and took temp readings for what its worth. The radiator 150 , heads were 215, water pump 200. If I had taken it for a run it would have blown again .
Here are a couple pictures of the radiator. Radiator core is 21 1/2 " X 18 1/2" I don't know the size of tubes as I've had this for several years . I'll try and find something on
it. Fan is a 16" fan did the paper trick in front grill fan sucked it up to the grill. I'm thinking a flow issue.


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IMG_20170626_163854927.jpg
IMG_20170626_163925829.jpg
 
Some of those types installations have problems they don't get enough air through them at speed, IE the fan actually becomes a restriction. Some shrouds have flappers on the rear so "ram air" forces them open and through the rad

fan shroud flapper vents - Google Search:
 
Some of those types installations have problems they don't get enough air through them at speed, IE the fan actually becomes a restriction. Some shrouds have flappers on the rear so "ram air" forces them open and through the rad

fan shroud flapper vents - Google Search:
Thanks Dell . Good read . My engine is getting hot at idle let alone pulling a load.
 
i don't see how air can get through that rad...at least half of it is completely blocked,unless that electric fan is moving 5000 + cfm
 
i don't see how air can get through that rad...at least half of it is completely blocked,unless that electric fan is moving 5000 + cfm
No I think about 2500. I did find the stats on it. Radiator is from CRF Performance . Cross flow 2- 1" tubes
 
No I think about 2500. I did find the stats on it. Radiator is from CRF Performance . Cross flow 2- 1" tubes

i've never used electric fans but have read a minimum of 3000 - 3500 cfm is usually required and think the Ford Taurus was a good piece among others.
 
i've never used electric fans but have read a minimum of 3000 - 3500 cfm is usually required and think the Ford Taurus was a good piece among others.
Tonight I'm going to measure pulleys. I think I'm good but want to make sure. I'm thinking
Maybe a high flow impeller and more fan
 
That fan is probably one of your issues. A mechanical fan with a shroud would do way better. If you're set on electric fans, look at the Contour/ Taurus fans that people on this site have had good luck with. Check Rock Auto for good pricing. That upper hose disrupts flow. Does the lower hose have a spring in it to keep it from sucking shut when you drive it. Get one from a Mustang parts supplier. You need to put the thermostat in a pot of water, and heat it up to verify opening temps. Buy a meat thermometer at the grocery store to test. I had some that didn't work properly.
 
Tonight I'm going to measure pulleys. I think I'm good but want to make sure. I'm thinking
Maybe a high flow impeller and more fan
Just measured pulleys .Crank pulley looked to be 7 5/8" and water pump 7" , so I'm almost 1 to 1 . Maybe this is a good starting point. Trade out stock impeller for high flow impeller and smaller pulley.
 
Pressure test...


But yeah... That shroud looks restrictive.
Fan is supposed to be shrouded. When I put it on it was set exactly to text. Blades in a 1/2" -1/2" out . I can put a paper in front and it will suck it right to the grill . I read a good read by Spall . They claim all electrical fans will loose as much as 700 cfm when in use that means my 2250 cfm fan is only making 1550 , not even enough to keep it cool in the shop.
 
That fan is probably one of your issues. A mechanical fan with a shroud would do way better. If you're set on electric fans, look at the Contour/ Taurus fans that people on this site have had good luck with. Check Rock Auto for good pricing. That upper hose disrupts flow. Does the lower hose have a spring in it to keep it from sucking shut when you drive it. Get one from a Mustang parts supplier. You need to put the thermostat in a pot of water, and heat it up to verify opening temps. Buy a meat thermometer at the grocery store to test. I had some that didn't work properly.

I like using an electric fan , as you know room is at a premium with a big block and I like the fact that at idle I'm pushing air through the radiator. When you get it right it works good. This is the first time with BB so I'm learning as I go. I think I need to step up water flow and maybe change fan,
. One step at a time. thanks for you input.
 
I said that shroud LOOKS restrictive. Deal with it... it does. if he isn't cooling at high speed, then he isn't getting enough air flow or coolant flow. until he pressure tests his system, we wont know if there are abnormalities. even with a shitty rad hose and stock water pump, he should cool.

You can always run a flowkooler, and a lower temp thermo... but it should be enough as is. For all you know a hose is leaking out a lbs or two of pressure, lower the boiling point but not leaking. OR... get a better fan design.

I daily drive my POS and beat the **** out of it and let it idle while im in the store or gas station... EVERYDAY. it hit 95 last week and my **** hit 205 at max. viscous fan, 22" champion rad, 185 thermo, dual circuit oil cooler in-front and utilizing the internal trans cooler. high initial timing and running slightly lean at idle.

I do run a cold air intake system so i dont breathe hot *** air. and I have coated and partially wrapped headers, an oil and power steering fluid cooler. BUT no hood scoop or vent to let out hot air. And when I say i beat the **** out of this car, I mean I am ruthless. I want the teener to pop so i can build a 408.

But for real, I cannot tell you how many cars I have worked on that leaked out pressure a bit on their hose clamps.
 
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