1970 Challenger 440 Heating Problems

[Orange Man]

I have gone through a lot of the posts on this site concerning heating issues with the 440 Magnum. Not many fit my situation. First of all, I bought this car from my friends widow. He bought it off of Ebay from the guy that restored it in Florida and had it shipped to Texas. I did not know my friend long before he pasted suddenly and he never mentioned overheating problems but then again he did not have it long and did not get to drive it much. I do not know if it was having heating problems then. The only thing he changed on the car was to put a Holley Sniper EFI. He had a lot of problems with it which some were caused by the installers.

Here is what I have done to it to try and fix the problem. I replaced the 13# radiator cap with a 16#. Ran the car and it heated up like before. I replaced the 160* thermostat with a 180* thermostat. It helped some but not much. I replaced all the plug wires because 5 out of 8 were burned through. They are too close to the headers but there is not much I can do except use plug wire looms and retainers. Runs better now.

Here is what is going on when it starts to heat up. Both electric fans are pullers. The bottom fan comes on at about 160*. It takes it several minutes before it gets to 180* The thermostat opens like it should, then the upper fan comes on when the temp gets to 180* but then the lower fan shuts off and will not come back on when the engine starts to heat up. The temp stays at about 195 for a while then goes to 210* and stays there for about 5 minutes then will steadly climb to 250* by then I will have shut it off. It takes driving about 20 minutes for all this to happen. I can hear the water gurguling in the radiator when it hits 235*. This is all on an 80 to 90 degree day. I use an infrared thermometer to check the temps. The temps at the thermostat housing are very close to the gauge.

Here are my thoughts. I think the EFI programing is screwed up and should allow both fans to run at the same time not just one. I think this because of all the clutter in front of the radiator and not enough grille to let a lot of air through to begin with. The radiator is a 2 row 26" radiator. The number of rows may be not enough for this setup. Also, there is a puller fan that pulls air away from the condenser towards the grille. It is actuated by the A/C switch on the dash. It does not run unless the AC is turned on. Should the fan in front of the AC condenser be a pusher which would push air towards the radiator instead of pulling air through the condenser towards the grille?

From friends of mine that got to know my friend "Will" before I met him, they said the car ran fine with no heating problems before Will had the Sniper put it. I am thinking that the programing got messed up and will not allow the bottom fan to come on. It gets awful hot in that engine compartment in 90+* Texas weather.

I think there is a combination of things going on that all contribute to the heating problem.

I was always a SBC guy and have been thrown into the Mopar crowd by purchasing this car. I like a challenge but this is begining to work on me because of the electronics stuff.
Please be gentle.

 

[Challenger RTA]

I would think you conclusions are correct. A combination of things. I'm not an EFI guy, but someone here is.
Nor am I a fan of Electric fans, and then there is the louvered cover? Maybe the front one maybe obstructing air flow.
The one thing I would like to add is to remove the water pump and inspect the impeller. Rusted away loose or other. I have experienced that even a new one.

 

[MoparCarGuy]

The Holley EFI kits allow you to set the Start and Stop temperatures for each fan. Obviously, since you see that both fans work, your EFI output to the fans are working to switch on your fan relays. Your next step would be to check the EFI settings for electric fan control.
On the Holley touchscreen, select Tuning>Basic>System>Outputs.
The menu allows you to set each fan independently for Start and Stop temperature.
A staggered setup is what most people run. Stagger the "Turn On" temperatures for the fans by 5-10°F so that they do not come on at exactly the same time. This reduces the initial current draw on your charging system.

If you are using the Holley computer software, the Electric Fans settings are under SYSTEM PARAMETERS>Basic I/O.
My settings are below for Holley Terminator X EFI. The menu can be a bit confusing but here is a summary.
Engine warms up to 195°F and Fan #1 turns ON. If temp drops to 190°F, Fan #1 turns OFF.
If temp continues upwards to 200°F, Fan #2 turns ON with Fan #1 already running. Both fans continue to run.
If temp drops below 200°F, Fan #2 turns OFF and Fan #1 keeps running unless temp drops less than or equal to 190°F.

My setting will be different than yours because I am running a factory clutch fan with two front-mounted SPAL pusher fans.
My electric fans are only for extremely hot days in traffic.

You may want to set your fans to come on at lower temps. You might consider these settings and test it out.
Fan #1 On 185°F Off 180°F
Fan #2 On 190°F Off 185°F

Check it out and let us know what the system had for settings.

 

[Ricks72Chlgr440]

Overheating can be caused by a number of things. A few of them are:

- retarded engine timing
- air/fuel ratio too lean
- improper coolant flow
- improper thermostat
- poor flow through the radiator

1. What is the initial timing set to?
2. I know you changed the thermostat, but did you install a high flow one? There is a big difference.

I had a 69 Charger 440 that would overheat. Found the thermostat was the correct temperature but was a low flow. Note the big "windows" in the thermostat shown.

Engine timing is a big part of cooling. In my 72 Challenger 440, I installed a Flowkooler water pump. I believe it is one of the very best, and moves a lot of water. Before you look at the fuel delivery, I would check the easy things first. Engine timing, thermostat type, and water pump operation.

 

[Adam]

I found the lower radiator hose, which is the suction hose, on my 70 Cuda would collapse when I revved it up. I discovered this by accident; but anyway… some radiator hoses come with springs in them, most do not. So at operating temp, open the hood and work the throttle while looking at the lower hose. Easy check, and easy fix if that is the problem.

Also, the EFI system allows you to look at the air/fuel ratio in real time; and it’s easily adjustable if you are running too lean.

 

[Orange Man]

Overheating can be caused by a number of things. A few of them are:

- retarded engine timing
- air/fuel ratio too lean
- improper coolant flow
- improper thermostat
- poor flow through the radiator

1. What is the initial timing set to?
2. I know you changed the thermostat, but did you install a high flow one? There is a big difference.

I had a 69 Charger 440 that would overheat. Found the thermostat was the correct temperature but was a low flow. Note the big "windows" in the thermostat shown.
View attachment 119913
Engine timing is a big part of cooling. In my 72 Challenger 440, I installed a Flowkooler water pump. I believe it is one of the very best, and moves a lot of water. Before you look at the fuel delivery, I would check the easy things first. Engine timing, thermostat type, and water pump operation.

I have not checked the engine timing yet. I did install a Mr. Gasket high flow 180* thermostat. Thermostat does open at it should and I can see good water flow through the radiator cap neck. I am suspecting that the bottom fan that cuts out when the top one kicks in is part of the problem. Process of elimination before I change to Flowkooler. Thanks

 

[Chryco Psycho]

The front fan is a major part of the problem , it needs to push air thru the rad not try to go against the airflow & pull towards the grille.
Electric fans are not nearly as efficient as a belt driven 5-7 blade & Having one not functioning is hurting you as well .
Timing can be a huge factor , , you need a minimum of 13* advance at idle increasing with RPM

 

[MoparCarGuy]

Yes, the A/C puller fan is a serious no problem as @Chryco Psycho said. First, get the main electric fans working together with the A/C off and temps under control. You can change out the A/C fan to a pusher later.

Your other cooler is contributing to heat at the A/C condenser and radiator. You should consider moving the smaller auxiliary cooler (transmission?) in your picture to another spot in the front valance.

 

[MoparCarGuy]

Another consideration with added EFI and electric fans is your charging system’s capacity. Do you know your alternator’s amp-rating? The EFI ECU plus the fans, aftermarket ignition, etc. need clean power (dedicated wiring) to operate correctly. A 100A Powermaster alternator is probably a minimum and separate control relays are a must for the fans to ensure they receive the proper voltage.

 

[Orange Man]

Yes, the A/C puller fan is a serious no problem as @Chryco Psycho said. First, get the main electric fans working together with the A/C off and temps under control. You can change out the A/C fan to a pusher later.

Your other cooler is contributing to heat at the A/C condenser and radiator. You should consider moving the smaller auxiliary cooler (transmission?) in your picture to another spot in the front valance.

The smaller cooler is for the rack & pinion powersteering fluid. The line is right next to one of the header tubes. It can not be moved because of the rack & pinion placement. My thought is like you mentioned, move the smaller cooler.

 

[Orange Man]

Another consideration with added EFI and electric fans is your charging system’s capacity. Do you know your alternator’s amp-rating? The EFI ECU plus the fans, aftermarket ignition, etc. need clean power (dedicated wiring) to operate correctly. A 100A Powermaster alternator is probably a minimum and separate control relays are a must for the fans to ensure they receive the proper voltage.

I have no clue on what the alternator rating is but I suspect it is only a 60 amp. I do notice that while working on the car and starting it and stopping it, the battery drops voltage and the engine gets harder to start. If it is fully charged, it starts pretty quick. Good info MCG

 

[MoparCarGuy]

I have no clue on what the alternator rating is but I suspect it is only a 60 amp. I do notice that while working on the car and starting it and stopping it, the battery drops voltage and the engine gets harder to start. If it is fully charged, it starts pretty quick. Good info MCG

Electric fans pull anywhere from 15-30 amps each. They can surge upwards of 30-40 amps due to startup current draw. A properly-sized alternator is a must with all of the accessories that EFI, etc. add to the electrical/charging system. A fan with <12VDC is not able to meet its design CFM rating.

I am running two 9" Spal pusher fans with two, separate 15 amp fused relays plus the 7-blade pulley driven fan with factory shroud. The 15A fan fuses are located at the relays under my Cuda's grille.
Spec sheet and my wiring diagrams below. Note that I am running a main power relay to an auxiliary fuse panel to power the EFI and other add-on accessories including an MSD shift light and LED tail lights.

 

[sixpactogo]

I agree with the responders that mentioned the puller fan in front of the condenser has to go. It is working against you in every way possible. The two puller fans on the engine side should be ample for your cooling needs but they should both run when needed. Not sure why the PO added that puller for the a/c but maybe to run a fan when the AC turned on. What is really needed is to replace the Binary switch mounted on top of the drier with a Trinary switch using the third wire to activate the fans when the AC is turn on. Another thing that could be causing your overheating may be the serpentine pulleys. I remember when I installed the March serpentine kit on my 70 440 Six Pack Challenger, it would overheat at an idle. I contacted March Performance and was told the March system was an "under drive system". Meaning the water pump ran slower than the factory system. I upgraded my water pump with a Flow Kooler high flow unit that helped some. but it would still get hotter than it should have. I didn't have electric fans on mine but I had the 20 seven blade fan with shroud and thermo clutch. If your alternator is a 60A unit, it should be up to the task.
If I were you, I would ditch the front fan, wire the engine side puller fans properly and maybe install a high flow water pump at minimum.
If you are worried about both fans starting at the same time and running full roar, overtaxing your alternator you could do as I did. Contact Darryl the Auto cool guy.
He will get you set up with his fan controller that works like the new cars do. The fans ramp up slow and slow down as temps rise and fall. You can get rid of the relays and high current flow at start-up and not have to listen to the fans roar at a stop light wearing out your fans for no reason. Here is a pic of my controller and Darryl's info if you want to call him. Good Luck!

 

[Orange Man]

Everyone says check the timing. Before I address the fan problem, I am going to check the timing. Since this is a Sniper EFI, do I check the manual timing and adjust it if necessary before I go to the timing parameters in the software? Also, what should the manual timing be? The owners manual says TDC for a 440 with a 4 barrel. What should it be in the software settings? Thanks J

 

[Ricks72Chlgr440]

Everyone says check the timing. Before I address the fan problem, I am going to check the timing. Since this is a Sniper EFI, do I check the manual timing and adjust it if necessary before I go to the timing parameters in the software? Also, what should the manual timing be? The owners manual says TDC for a 440 with a 4 barrel. What should it be in the software settings? Thanks J

You cannot go by what the factory said about initial timing, as every engine/car combination may want something different. They did that for emissions reasons, not performance or best operation. Start around 12-14 and see how it runs. Lots of posts about how to tune your timing but the best thing is to give your engine what it wants, including the timing curve. In my 440, I run 18 initial and all in is around 36. I also run manifold vacuum since the engine likes it!

 

[plymouth67]

Something I see in the picture of your engine that nobody has mentioned yet would be the aftermarket pulleys. I just went through this with the 512 in my Challenger. I changed the radiator to a different one with the aluminum shroud with 2 fans in it but, the one thing I think is going to help the most is changing the crank pulley. My car has CVF aluminum pulleys on and, the crank pulley was an under drive unit so, it was much smaller than the water pump pulley causing the water pump to turn much slower. I ordered the larger (stock) size aluminum pulley and swapped it out. You could literally fit that smaller crank pulley inside of the stock size pulley. This speeds up the water pump. It seems much better but, I will really find out come July. I think a lot of people buy these aftermarket pulleys because they are aluminum and look pretty but, they don't understand the diameter of the pulleys and, what changing that diameter does.

 

[sixpactogo]

Something I see in the picture of your engine that nobody has mentioned yet would be the aftermarket pulleys. I just went through this with the 512 in my Challenger. I changed the radiator to a different one with the aluminum shroud with 2 fans in it but, the one thing I think is going to help the most is changing the crank pulley. My car has CVF aluminum pulleys on and, the crank pulley was an under drive unit so, it was much smaller than the water pump pulley causing the water pump to turn much slower. I ordered the larger (stock) size aluminum pulley and swapped it out. You could literally fit that smaller crank pulley inside of the stock size pulley. This speeds up the water pump. It seems much better but, I will really find out come July. I think a lot of people buy these aftermarket pulleys because they are aluminum and look pretty but, they don't understand the diameter of the pulleys and, what changing that diameter does.

I agree with the underdrive pulleys being a problem. I did mention them yesterday in post 13. It was an issue with my 70 Challenger many years ago with the March serpentine pulleys. I was not aware that they tooled up for a larger water pump pulley but yes, it would help move the coolant for sure.

 

[Chryco Psycho]

I agree , timing should be at least 12* at idle 16-20 is possible .

 

[Orange Man]

I agree , timing should be at least 12* at idle 16-20 is possible .

I got a chance to do a little research after my ranch duties. I checked the timing and it is approximately 5* BTC, this is at idle 980 rpm and stays there at about 1800 rpm. I checked the Sniper monitor and it shows no timing at all. Is 12* on the end of the tab?

 

[Orange Man]

I agree with the underdrive pulleys being a problem. I did mention them yesterday in post 13. It was an issue with my 70 Challenger many years ago with the March serpentine pulleys. I was not aware that they tooled up for a larger water pump pulley but yes, it would help move the coolant for sure.

I measured my water pump pulley and it is a 6" (5" 13/16") pulley. Is this an underdrive pulley? I could not find specs on the March pulleys. I don't know if these are March pulleys.