Is my cooling system operating normal?

[67_Slimer]

My 67 Dart with a typical built 10.5/1 340 , aluminum heads. I revamped my cooling system this offseason and thought I would get better results but maybe I'm being unrealistic. I have a Champion 3 row aluminum radiator , put all new hoses , Mr. Gasket 160 degree high flow thermostat , offhand I'm not sure of the fan size but its a clutch fan. I also have a 16 inch pusher electric fan for assistance. I have 4.56 gears with a 27 inch rear tire so it revs while cruising. I was cruising in 4th around 2500 to 2700 rpm on a 90 plus degree day with my electric fan on and the car was at it's hottest around 190 deg. I'm just wondering if my setup should be doing better or it's working to its potential? Any info helps. Thank you.

 

[Demonx2]

My avatar 408 runs a tad cooler (maybe 180-185-ish) with a pair of electric fans running in 90+ degree weather at those rpms. I'm happy with it as it will stay there or goes down slightly when stopped at a light or whatnot.

As for a mechanical fan, make sure you have a good shroud on it and the top of the clutch is about 1/2 to 3/4" from the rad. If the mech is set up properly, you might find the pusher electric is in the way/blocking airflow and can be removed.

 

[TrailBeast]

My 67 Dart with a typical built 10.5/1 340 , aluminum heads. I revamped my cooling system this offseason and thought I would get better results but maybe I'm being unrealistic. I have a Champion 3 row aluminum radiator , put all new hoses , Mr. Gasket 160 degree high flow thermostat , offhand I'm not sure of the fan size but its a clutch fan. I also have a 16 inch pusher electric fan for assistance. I have 4.56 gears with a 27 inch rear tire so it revs while cruising. I was cruising in 4th around 2500 to 2700 rpm on a 90 plus degree day with my electric fan on and the car was at it's hottest around 190 deg. I'm just wondering if my setup should be doing better or it's working to its potential? Any info helps. Thank you.

Lots of heat events with low gears.
That said, 190 isn’t bad.
Also, 3 row radiators can actually be a detriment.
Core tube size is sometimes more important than row count.
I run a 26 inch 2 row with 5/8 tubes here in AZ with zero issues.

 

[67_Slimer]

My avatar 408 runs a tad cooler (maybe 180-185-ish) with a pair of electric fans running in 90+ degree weather at those rpms. I'm happy with it as it will stay there or goes down slightly when stopped at a light or whatnot.

As for a mechanical fan, make sure you have a good shroud on it and the top of the clutch is about 1/2 to 3/4" from the rad. If the mech is set up properly, you might find the pusher electric is in the way/blocking airflow and can be removed.

It's funny you say that because It seems like after I installed the electric fan it ran a tad warmer. Seems weird because if it's on wouldn't it create more airflow? Also would I be better off with dual electric fans instead of my current setup?

 

[Demonx2]

If youre running 190 down the road and it doesn't go higher when idling, I'd day you're all good and leave it alone. But if you find the mechanical only insufficient at idle (just switch off the elec fan to run the test), then that tells you that you need the elec fan at idle and I would keep it.

As for dual electrics only, there are numerous combative threads on here you can search and read. I run a Jegs dual electric puller setup that comes in its own shroud. I sealed that shroud up pretty good to the rad and I've not had any issues with it here in Florida heat (mid-90's). As there's not really any bracket racing in the summer down here, I add street tires and mufflers to the car and use it on the streets. Then start over with the slicks and open headers for racing again in the fall.

I do not run the trans fluid through it as I have a separate Derale cooler/fan for the trans. The only time I feel the need to run that fan is after a pass at the track where it will hit 190-ish. Flip the fan on and by the time I'm back to my pit, it's usually back down to 160-ish. (Keep in mind I run an 8" converter that flash stalls at 5000rpm at the track.)

 

[67_Slimer]

If youre running 190 down the road and it doesn't go higher when idling, I'd day you're all good and leave it alone. But if you find the mechanical only insufficient at idle (just switch off the elec fan to run the test), then that tells you that you need the elec fan at idle and I would keep it.

As for dual electrics only, there are numerous combative threads on here you can search and read. I run a Jegs dual electric puller setup that comes in its own shroud. I sealed that shroud up pretty good to the rad and I've not had any issues with it here in Florida heat (mid-90's). As there's not really any bracket racing in the summer down here, I add street tires and mufflers to the car and use it on the streets. Then start over with the slicks and open headers for racing again in the fall.

I do not run the trans fluid through it as I have a separate Derale cooler/fan for the trans. The only time I feel the need to run that fan is after a pass at the track where it will hit 190-ish. Flip the fan on and by the time I'm back to my pit, it's usually back down to 160-ish. (Keep in mind I run an 8" converter that flash stalls at 5000rpm at the track.)

OK , well I have a 4 speed so no cooling situations with that. I also have zero shroud. I'm sure that's a lot of my issue?

 

[Demonx2]

Issue only if you believe 190 to be an issue. But a mechanical fan will always work better with a proper shroud around it.

 

[Demonx2]

One other thing to keep in mind. There are 2 radiator companies out there and people don't usually segregate which one they have.

There are Champion Radiators and Champion Cooling System radiators. I run the latter and am quite pleased. I don't hear people touting the first one I note (Champion Radiators) but it's hard to know which one they really have.

 

[67_Slimer]

One other thing to keep in mind. There are 2 radiator companies out there and people don't usually segregate which one they have.

There are Champion Radiators and Champion Cooling System radiators. I run the latter and am quite pleased. I don't hear people touting the first one I note (Champion Radiators) but it's hard to know which one they really have.

Good to know , I'll check that out. Thank you for your time.

 

[69hemibeep]

190 is perfect leave it alone

 

[dano]

What's the tune on the engine? Too lean and too retarded on timing can cause overheating heat too. Might need a bit more initial or lessen air though the idle or both.

As said 190 is ok. A shroud with help.

 

[Syleng1]

I’ll chime in on this subject.
Why 160 t stat? Run a high flow 180. When the thermostat is open solid… there is not time for fluid to slowdown and actually get cooled in the radiator. It is flowing pretty fast with those gears/engine rpm.
Also, I’m not a fan of aluminum radiators. I run copper and have not had good heat loss from aluminum. Most like aluminum because they are cheaper, lighter and more forgiving than copper. I do agree on tube size. 2 rows of 5/8 is better that 3 rows of 3/8.

Also, all that motor and the same sized radiator opening. More hp requires more surface area for street driving and big gears.
Syleng1

 

[Dana67Dart]

My 67 Dart with a typical built 10.5/1 340 , aluminum heads

Nice, not out of the realm of normal for a dart.

I revamped my cooling system this offseason and thought I would get better results but maybe I'm being unrealistic

Probably!

. I have a Champion 3 row aluminum radiator , put all new hoses

Most likely you have plenty of cooling ability.
How thick is the core?

Mr. Gasket 160 degree high flow thermostat

Some will argue with me about this (RRR ) but a 160 deg thermostat ONLY sets the lowest low temp the engine will run. Think like in Alaska in the winter the engine will be running at the thermostat temp. But in the desert in the summer it will be running above the thermostat temp. That means the thermostat is wide open and the engine / engine tune, water pump, pulleys, radiator, airflow, outside air temp, etc. will determine the temp the engine runs at.

Once the thermostat is wide open it does nothing for the cooling system.

offhand I'm not sure of the fan size but its a clutch fan. I also have a 16 inch pusher electric fan for assistance.

Above 30 miles per hour the fans have little to no effect on the cooling system, unless you have an airflow blocking issue.

If you don't have trouble maintaining a temp at idle with just the mechanical fan, the electric is not needed.

I have 4.56 gears with a 27 inch rear tire so it revs while cruising.

Not relevant. Just the actual rpm the engine is running at a given speed.

. I was cruising in 4th around 2500 to 2700 rpm on a 90 plus degree day with my electric fan on and the car was at it's hottest around 190 deg.

2500 to 2700 is not particularly high by our cars standards. Modern cars with OD, 500 to 1000 RPM high

By my calculations you were doing about 50 mph, more than fast enough to not need any fans.

You engine maintained 190, that's where it wants to run based on your cooling systems efficiency, and ALL the other aspects of your engine combination.

I'm just wondering if my setup should be doing better or it's working to its potential? Any info helps. Thank you

I think it is working great.
Put in a high flow 180 deg thermostat so you don't run the engine too cold. Test without the electric fan, source a OEM style shroud, NOT the aluminum type that are a fraction of an inch from the core and parallel to the core, they actually block airflow at speed due to their design.

 

[72bluNblu]

Seems like the old wives tales are back in force.

- You can't circulate water too fast through your radiator. This is 100% bullshit, no one that knows anything about fluid dynamics or thermodynamics would tell you this. It's been proven again and again, but this misinformation will never die.

- You don't need a 160° thermostat unless your car is tuned to run at 160°. Once the thermostat opens, it's not doing anything for your cooling system anymore. Running a colder thermostat by itself does not reduce your cooling system temperatures- the entire cooling system has to be tuned to work in a certain range . On the street there is no reason to have a 160° thermostat. For a drag race only car, sure, you can cool it between runs and get that extra few horsepower.

- Aluminum radiators work just fine in literally millions of cars, and tube size vs # of rows is far more complicated than "bigger tubes are better". Unless someone runs the calculations and can show the results to you, saying a two row is better than a 3 row is just them buying into marketing hype. Some 2 rows are better than some 3 rows, some 3 rows will be better than some 2 rows. If you don't have the actual numbers, you don't know which is better in a particular case.

Now, on to your specific set up. Your pusher fan is blocking air flow by being in front of the radiator, and on top of that it shouldn't need to run at all once you're going more than 20 mph. The fan running at highway speeds is in fact reducing your air flow vs not having it there at all. Your 3 row Champion radiator can work just fine, I ran a 26" 3 row Champion in my Duster for almost 10 years with a dual electric fan set up (stand alone puller) on a 9.8:1 340 with ported iron heads pushing more than 400 hp and running the car a daily driver. I still run a 3 row aluminum radiator in front of it now, just a KKS because Champion changed the dimensions on their 26" 3 row.

You shouldn't need an electric fan in addition to a mechanical fan. Your mechanical fan by itself should be capable of cooling that combination. You should have a good fan shroud on there to maximize the efficiency of your mechanical fan. In addition to that, you need to make sure you have your pulley ratio's matched to the type of water pump you're running. Ma Mopar had multiple pulley ratio's, as well as two different output water pumps. If you've got a mismatch you will not be running the fan and water pump at the right speed for maximum efficiency.

All of that said, 190° isn't bad at all for 90°+ degree weather for a street car. I run a 190° thermostat in my car, my fans aren't even programmed to come on until 200°. I run a dual electric fan set up from a Ford Contour, the high speed has only come on when it was 110° and I was stuck in traffic. Now for a drag strip only car you wouldn't want to be running at that high of a temperature, but for a street car it makes no sense at all to tune for 160°.

 

[Dana67Dart]

When the thermostat is open solid… there is not time for fluid to slowdown and actually get cooled in the radiator. It is flowing pretty fast with those gears/engine rpm.
Also

I used to think that too but it is not the case. It is a wives tail, and has been debunked several times here and elsewhere.


If the fluid is going slow through the core it is also going slow through the block, slow fresh cool fluid entering the block means slow cooling of the block.

 

[67_Slimer]

Seems like the old wives tales are back in force.

- You can't circulate water too fast through your radiator. This is 100% bullshit, no one that knows anything about fluid dynamics or thermodynamics would tell you this. It's been proven again and again, but this misinformation will never die.

- You don't need a 160° thermostat unless your car is tuned to run at 160°. Once the thermostat opens, it's not doing anything for your cooling system anymore. Running a colder thermostat by itself does not reduce your cooling system temperatures- the entire cooling system has to be tuned to work in a certain range . On the street there is no reason to have a 160° thermostat. For a drag race only car, sure, you can cool it between runs and get that extra few horsepower.

- Aluminum radiators work just fine in literally millions of cars, and tube size vs # of rows is far more complicated than "bigger tubes are better". Unless someone runs the calculations and can show the results to you, saying a two row is better than a 3 row is just them buying into marketing hype. Some 2 rows are better than some 3 rows, some 3 rows will be better than some 2 rows. If you don't have the actual numbers, you don't know which is better in a particular case.

Now, on to your specific set up. Your pusher fan is blocking air flow by being in front of the radiator, and on top of that it shouldn't need to run at all once you're going more than 20 mph. The fan running at highway speeds is in fact reducing your air flow vs not having it there at all. Your 3 row Champion radiator can work just fine, I ran a 26" 3 row Champion in my Duster for almost 10 years with a dual electric fan set up (stand alone puller) on a 9.8:1 340 with ported iron heads pushing more than 400 hp and running the car a daily driver. I still run a 3 row aluminum radiator in front of it now, just a KKS because Champion changed the dimensions on their 26" 3 row.

You shouldn't need an electric fan in addition to a mechanical fan. Your mechanical fan by itself should be capable of cooling that combination. You should have a good fan shroud on there to maximize the efficiency of your mechanical fan. In addition to that, you need to make sure you have your pulley ratio's matched to the type of water pump you're running. Ma Mopar had multiple pulley ratio's, as well as two different output water pumps. If you've got a mismatch you will not be running the fan and water pump at the right speed for maximum efficiency.

All of that said, 190° isn't bad at all for 90°+ degree weather for a street car. I run a 190° thermostat in my car, my fans aren't even programmed to come on until 200°. I run a dual electric fan set up from a Ford Contour, the high speed has only come on when it was 110° and I was stuck in traffic. Now for a drag strip only car you wouldn't want to be running at that high of a temperature, but for a street car it makes no sense at all to tune for 160°.

Thank you so much for this. So in turn , should i remove my mechanical fan to lighten up the weight from my pump or should I remove the electric and go just mechanical?

 

[Dana67Dart]

One last thing...

The pulley ratio needs to match the water pump design.

On 273 and 383 the ratios are .95 and 1.4

With .95 the wp has a larger dia impeller (4.2 to 4.4") and the number of vanes is higher at 10.

With 1.4 the wp has a smaller dia impeller (3.5 to 3.6") and the number of vanes is fewer at 6.

They have to match, a .95 ratio pulley with 1.4 pump and you most likely will not have enough flow.

1.4 ratio pulley with a .95 pump you will most likely have cavitation resulting in lower flow

 

[Inertia]

This is one of the most helpful cooling system 3d vids I have found, that gives a complete rundown of how the whole system works together.
Please note how the thermostat modulates to keep the temp at the "stamped" temp, and only opens fully when the rad cannot cope with the heat being created.

Low heater temp in winter is usually a stuck full open thermostat, - the rad capable of shedding +/- 60* of heat lowers the coolant temp way below comfortable, - the heater blows cold air, cuz the thermostat isn't partially closing to modulate the coolant.

Watch the vid, particularly the operation of the thermostat, skip the ad.
Cheers

 

[72bluNblu]

Thank you so much for this. So in turn , should i remove my mechanical fan to lighten up the weight from my pump or should I remove the electric and go just mechanical?

In your situation I would remove the pusher electric fan. More than likely that fan doesn’t push enough air (CFM) to be a standalone fan.

With the electric fan removed you can then see where you’re at with the mechanical fan, but based on what you’ve said already you should add a fan shroud. You should also measure your fan and crank pulley diameters to make sure you’ve got a pulley ratio that’s correct for your application. What water pump are you running?

I’m all for electric fans, but running a stand alone electric fan on the street is a lot more involved than just taking the mechanical fan off and slapping an electric fan on. The fan has to be able to flow enough CFM, which typically requires a higher output alternator and a heavy duty relay system. It also needs a good controller for street use, which usually needs its own sending unit, etc. A strip only car can get away with a simple on/off, but that’s not how you want to run on a street car. So unless you’ve already set some of that up, it would be easier to just remove the pusher and figure out what your cooling system needs to run efficiently (shroud, proper pulley ratio, etc)

 

[67_Slimer]

In your situation I would remove the pusher electric fan. More than likely that fan doesn’t push enough air (CFM) to be a standalone fan.

With the electric fan removed you can then see where you’re at with the mechanical fan, but based on what you’ve said already you should add a fan shroud. You should also measure your fan and crank pulley diameters to make sure you’ve got a pulley ratio that’s correct for your application. What water pump are you running?

I’m all for electric fans, but running a stand alone electric fan on the street is a lot more involved than just taking the mechanical fan off and slapping an electric fan on. The fan has to be able to flow enough CFM, which typically requires a higher output alternator and a heavy duty relay system. It also needs a good controller for street use, which usually needs its own sending unit, etc. A strip only car can get away with a simple on/off, but that’s not how you want to run on a street car. So unless you’ve already set some of that up, it would be easier to just remove the pusher and figure out what your cooling system needs to run efficiently (shroud, proper pulley ratio, etc)

I'm sorry , I didn't post that , it's a flowkooler mechanical water pump.

 

[Dana67Dart]

it's a flowkooler mechanical water pump

What are you crank and water pump pulley diameters

 

[Uncle Bob]

As for a mechanical fan, make sure you have a good shroud on it and the top of the clutch is about 1/2 to 3/4" from the rad.

Another thing to pay attention to is the pitch. You want as much of that as you can get. Flat fans don't draw enough air.

What are you crank and water pump pulley diameters

FWIW I went on a search to correct my factory sized 4% underdrive pulley setup and found a "high volume" 1:1 setup at CVF with the difference being the waterpump pulley. I replaced that and my fan at the same time so I can't say which one fixed it, or if they both helped a little bit, but my car doesn't run hot now. (I also have a flow kooler and a Cold Case radiator - those didn't help until I changed the pulley and fan.)

 

[Dana67Dart]

. I replaced that and my fan at the same time so I can't say which one fixed it, or if they both helped a little bit, but my car doesn't run hot now. (I also have a flow kooler and a Cold Case radiator - those didn't help until I changed the pulley and fan.

That's what the factory did. Speed up the fan and pump but used a less efficient pump to maintain the same flow?

 

[72bluNblu]

That's what the factory did. Speed up the fan and pump but used a less efficient pump to maintain the same flow?

So the factory AC cars got a 6 vane water pump with a smaller impeller and were run at a pulley ratio of 1.3 or 1.4:1 depending on the engine/car etc. The non-AC cars got an 8 vane water pump with a larger impeller but a .95:1 pulley ratio. Here's the factory pulley ratio's, as well as the fan diameters, water pump impeller size and radiator sizes. You can see that for most of the applications the AC option also upsized the radiator, with a few performance engine exceptions.

Obviously I don't know for sure, but my somewhat educated guess would be that the factory wanted to move more air to cool the loads incurred from running the AC equipment more so than increase water flow. But of course with a mechanical fan you can't spin the fan faster to push more air without spinning the water pump faster too. So they sized the water pump down. But that may have had more to do with water pump cavitation because of the impeller speed than just the actual flow rate. I think it's probably assuming too much to say the flow rates stayed the same without actually seeing the GPM numbers for the pumps. It may have just been because of the pump efficiency at the higher RPM, or even the rated RPM of the pump impellers, with the larger impeller being rated for a lower peak operating RPM. I mean, if you're at 1.4:1 instead of .95:1, and you spin your engine up to 6k RPM the pump impeller goes to 8,400 rpm vs 5,700. That's a BIG jump.

Problem is most water pump manufacturers don't publish GPM vs RPM graphs. For small block applications you just get "high volume" or "low volume" and if you're lucky an impeller vane count. But you'd have to compare the GPM outputs of the pumps, and even then you'd be comparing those outputs at different engine and pump RPM's to be apples to apples.

 

[Dana67Dart]

Problem is most water pump manufacturers don't publish GPM vs RPM graphs. For small block applications you just get "high volume" or "low volume" and if you're lucky an impeller vane count. But you'd have to compare the GPM outputs of the pumps, and even then you'd be comparing those outputs at different engine and pump RPM's to be apples to apples.

throw in an orange in there too as a newer vane design might be more efficient so it needs fewer to achieve the same flow at a specific RPM and lets not forget about static pressure! Pushing against a restrictive radiator design would impede the flow, a pump that can push harder can overcome the restriction compared to one that can not.

DANG now we have to add kiwi to the mix!