General Tech Check my cooling system math for errors please

[Jay5.9L]

The 4.0L swapped into my CJ has always ran warm when the ambient temp goes into the 90's and above. It has a good factory replacement style radiator but the previous owner installed a E-fan with out a should which I think is causing the problem.

Please check my math. And yes I want to stick to a e fan vs. converting back to a mechanical for now.

Ford Contour fan: supposed to fit a CJ radiator like a glove and has ~3400 CFM


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Derale PWM Controller: soft start and can control multiple fans


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Inline radiator hose adapter: the Derale controller down fall is that the temp signal from the radiator probe can be suspect so a inline hose probe will solve it.



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Cool Jeep

 

[bryson]

Looks like sound math to me... That Contour fan should do just fine.

 

[TurboMinivan]

Yep, that all looks good.

Another option (if you're on a budget) would be to skip the Derale controller and instead find a Volvo relay in a junkyard.

Go ahead and buy that same hose adapter, but insert a temp sensor that sends out a 'ranged' signal (ie, on at 210^, off at 195^), such as this one.

Assuming your thermostat is below 195^ (in this example), that should work very well.

 

[Greg]

Having a shroud should make a huge difference, IMO! If it's still a little warm, add a bottle of Water Wetter to your coolant.

 

[Jay5.9L]

I saw the Volvo relay setup and that may be an option. I like the idea of a soft start and a variable speed to keep the noise and the amp spikes down. Did water wetter and purple ice over the years. Think it helped a little but not where I feel comfortable driving in the heat.

 

[TurboMinivan]

I saw the Volvo relay setup and that may be an option. I like the idea of a soft start and a variable speed to keep the noise and the amp spikes down.

Yeah, I understand. Depending on exactly how many amps that Contour fan draws, the soft start feature may be a very nice thing to have.

I am using the Volvo relay in my Grand Prix, which is why I am familiar with it. The fan/shroud I currently have installed (from a Dodge Spirit) doesn't draw so much power that it blows any fuses. After the engine swap, I will almost certainly need to upgrade to a better fan; we'll see if the rest of my setup can handle its power needs.

 

[Jay5.9L]

I've read the fans can spike up to 40 -60 amps total so the controller should work fine

 

[Jay5.9L]

Its been a while so here is a an update. After much work, rework, leak fixing, new hoses, t-stat, etc, adding a last minute trans cooler, the system seems to be working well. The previous owner never checked the over flow tank. The nipple for the radiator tube did not have a hole so the tank was doing nothing! I wondered why my hoses were always deflated when cold. Other than the space in between the terminals being a little tight, the PWM controller is a nice unit. Works as advertised. I need to turn down the setting so it comes on a bit earlier. It takes 30 seconds to ramps up and at max speed the twin fans suck a ton of air and are fairly quiet compared to the old generic straight bladed fan. We will see how it works in the summer heat. And why are my pictures always inverted after upload?

 

[Omgbecki]

That's a cool update. How tight is that fit?

 

[Jay5.9L]

The fan to radiator is almost perfect, just a little space at the top and bottom that is not covered but the shroud. Since the fans are offset on each side the water pump clearance is pretty good. Maybe 2 inches between it and the shroud. Looks fairly "factory" if I painted the aluminum brackets.

 

[Kevin B.]

Having a shroud should make a huge difference, IMO! If it's still a little warm, add a bottle of Water Wetter to your coolant.

I'm going to derail Jay's thread, do you still like this stuff? Any idea what sort of temp difference you saw after putting it in?

 

[Jay5.9L]

Hard to tell. The old system would be fine then in certain situation just start running hot. I think it was a combination of the blocked over flow and low air movement. For $10 it's cheap insurance. I threw a bottle in when I filled back up (twice since I nicked a tube and had to drain and rip everything out again to get it repaired).

 

[jackjoh]

This thread has been interesting, Thanks to everyone.

 

[Omgbecki]

I'm wondering if that would be better then my fan idea. Do you know how wide your rad is?

 

[Jay5.9L]

I can go home and pull a measurement. Your more than welcome to swing by and look if you want.

 

[Greg]

I'm going to derail Jay's thread, do you still like this stuff? Any idea what sort of temp difference you saw after putting it in?

It's been YEARS since I ran it, I used to sell it when I worked at a Speed Shop. It would reliably drop running temps by 10-20*, but works better with less coolant and more water. It breaks the surface tension of the water, allowing it to better absorb heat. It's neat stuff, but won't fix a cooling system that isn't properly sized or has some other glaring issue.

https://www.redlineoil.com/content/files/tech/WaterWetter Tech Info.pdf

DYNO TEST RESULTS;

Dynomometer tests performed by Malcolm Garrett Racing Engines showed significant improvements in coolant temperatures using WaterWetter. These tests were performed with a Chevrolet 350 V-8 with a cast iron block and aluminum cylinder heads. The thermostat temperature was 160°F. The engine operated at 7200 rpm for three hours and the stabilized cooling system temperature was recorded and tabulated below:

50% Glycol/ 50% Water- 228°F
50/50 with WaterWetter- 220°F
Water- 220°F
Water with WaterWetter- 202°F
These numbers are similar to the temperatures
recorded in track use and heavy-duty street use.

 

[Jay5.9L]

Interesting data Greg I used both Red Line water wetter and Royal Purple purple ice over the years and assume they are the same thing/idea just different companies and color. For $10 you really cant go wrong.