440 heating only on highway speeds

[josephqatarcarguy]

hey guys,

my 1973 challenger 440 auto goes upto 210 - 220 only if driving at 3000 rpms constant on the highway , comes down when driving normal / stuck in traffic, 4 core rad , high flow dual fans , high flow waterpump , 180 thermostat
i live in qatar and the weather here is 110f or so , it that normal and alright? when the weather gets down to 95 100 she runs a steady 180 -200 , she has never puked over or anything.

built 440 - dont know specs but she idles at 950 , 7.5 inch of vacuum at idle - mean idle .

Let me know guys

 

[451Mopar]

I found the 4-core radiator I was using was real thick and made it hard to get air flow through the radiator.
I switched to a Griffin 2 core, but the cores are 1.25", so pretty much the same capacity as the 4-core, but the overall thickness is thinner.
Wow, prices have really gone up since I bought mine. looks like they are around $1,000 now.

 

[dan juhasz]

I agree 4 core radiators have small tubes , clog quickly and in general don’t allow air to flow through easily.

 

[WileE]

hey guys,

my 1973 challenger 440 auto goes upto 210 - 220 only if driving at 3000 rpms constant on the highway , comes down when driving normal / stuck in traffic, 4 core rad , high flow dual fans , high flow waterpump , 180 thermostat
i live in qatar and the weather here is 110f or so , it that normal and alright? when the weather gets down to 95 100 she runs a steady 180 -200 , she has never puked over or anything.

built 440 - dont know specs but she idles at 950 , 7.5 inch of vacuum at idle - mean idle .

Let me know guys

I'll assume you got 3.91 or 4.10 in the rear ? I'd like to know how much airflow is being impeded by those "high flow dual fans" .

 

[josephqatarcarguy]

I'll assume you got 3.91 or 4.10 in the rear ? I'd like to know how much airflow is being impeded by those "high flow dual fans" .

3.5 rear gears and 4000 cfm , don't think it has anything to do with fans mate , I run them on all the cars I've built and they work fine in this weather

 

[69hemibeep]

220 is at the top of the normal operating range just as long as it doesn't keep going up. Got a spring in the lower hose?

 

[rickseeman]

That's what I was thinking. No spring in the lower hose.

 

[josephqatarcarguy]

220 is at the top of the normal operating range just as long as it doesn't keep going up. Got a spring in the lower hose?

Yes I do

 

[451Mopar]

I would run an external transmission cooler and plumb the trans output to the external cooler before the radiators cooler. Running with the trans outlet into the radiator makes the radiator do extra work cooling the hot trans fluid along with the engine.
Not sure if you have A/C, but the condenser blocks air flow and also adds heat in front of the radiator when using the A/C. Not sure if a pusher fan on the A/C condenser would help or hurt?

 

[josephqatarcarguy]

I would run an external transmission cooler and plumb the trans output to the external cooler before the radiators cooler. Running with the trans outlet into the radiator makes the radiator do extra work cooling the hot trans fluid along with the engine.
Not sure if you have A/C, but the condenser blocks air flow and also adds heat in front of the radiator when using the A/C. Not sure if a pusher fan on the A/C condenser would help or hurt?

I do have an external cooler for the transmission and I took out the fan in front of the AC condenser as I figured it would block air flow since it's only gets to higher temps on the highway

 

[mopar 3 B]

Have you cheeked radiator temperatures at the inlet and outlet? A lean running engine also creates more heat. Just trying to determine if this is truly a radiator problem or if problems exist elsewhere.

 

[1 Wild R/T]

On modern cars the computer typically turns on the fan to low at 221 degrees

 

[mopar 3 B]

At highway speeds of what good are the fans? If the isn't enough air flow into the radiator going down the road at speed fans are not going to help. After all air is being forced threw the grill into the radiator.
Infact, I have used that air flow to turn the solid mount fan to turn the water pump. It kept the engine cool as long as the air flow was maintained. This is the reason I don't see this as a fan problem. Fan problems should only occur at lower speeds and while parked.

 

[Demonic]

Flow restriction. Try a high flow thermostat. The actual opening section should be 1 7/16" Summit has the EMP Stewart brand.

 

[josephqatarcarguy]

Flow restriction. Try a high flow thermostat. The actual opening section should be 1 7/16" Summit has the EMP Stewart brand.

Already got one mate , i think its just the weather here....110 -113f and it just runs in the upper heat range ... like i said if the weather comes down to 90 - 100f she runs 180-190 all day

 

[#41]

What do the plugs look like after a highway run? A vacuum leak can be cause a lean / run hot condition at higher speeds.

 

[Demonic]

Already got one mate , i think its just the weather here....110 -113f and it just runs in the upper heat range ... like i said if the weather comes down to 90 - 100f she runs 180-190 all day

Ah. Well, the other rule of thumb for Mopars is - your radiator is dirtier inside than you think. Lay it on it's back and fill it with a gallon or two of white vinegar, let it sit for 12 hours, then flush the heck out of it, opposite normal flow.

 

[bm02tj]

If the water flow is to fast it will not release its heat
Try driving at lower speed and gear so motor is at 3000 and see if same result if so add a restrictor or lower flow water pump

 

[1967coronet]

There are different diameter pulleys for A/C and non A/C cars, also different water pump impeller vane count between the two.
Not sure if this is a factor on your car but could reduce coolant flow at higher rpms.
Just a shot in the dark.

 

[Geoff 2]

Didn't read all the posts but a high probability that your fans are acting like a baffle at highway speeds. Get rid of them & use a factory clutch fan. Also, w/pump should be overdriven 10-20%.

More info here: www.stewartcomponents.com