[Robbert D 70`Chally (383m]

Cooling system improvements

While my tranny is out I have easy opportunity to upgrade my cooling system. The Mopar cooling systems are said to be not too efficient. I have a 26” 3 row radiator, but capacity (the “Max Cool system”) on hot days above about 25 centergrade (77 Fahrenheit) is not enough. Getting in a traffic jam after an hour driving at 120kmh (75mph) leads to a watertemp meter indicating about 70 percent (original meter). This may also occur without the highway part, if it is hotter. An immediate stop at a gas station may imply 3 quarters of a liter (about 1 and a half a pint, be it imperial or united) of cooling liquid being thrown out.
Oh by the way, she is drinking LPG these days, not gasoline. LPG burns hotter.

Measurements:
(the “canals” in the engine are allready cleaned)
-My radiator is being cleaned, meaning airflow and waterflow is taken care of. I consider the radiator suspect #1.
-A transmission cooler of maximum dimensions is being mounted. This should restrict the thermal energy dissipation (?) of the ATF element in the radiator.

I have a 18” flex fan mounted, the original fan is 19”. (A flex fans are fans that are supposed to save a couple of horses by flattening out at high rpm to reduce drag, save weight and save the waterpump bearing too. Available from 12” to 19” in increments of 1). There is no shroud.
I am considering to find a shroud and mount it.
Thermostat has to be checked, I forgot whether the last owner did that or not.
There seem to be certain “air leading” rubber or steel parts available, that close the gap in the front valance panel and between the radiator grille and the small beam/strip the radiator top is close to. I don’t have them.

Any comments? Do I need the shroud? Will it be of use considering the one inch smaller than original flex fan? Do I need those “airconductors”?
What about those aftermarket high volume low weight waterpumps? And the “Flow Kooler water pump conversion disc” claiming 60% increase of flow for $5.95?
I think coolin science in general is not widely spread, so this is trial and error country I am afraid. Any experience considering an upgrade of the cooling system for my 383 is appreciated.

[Robbert D 70`Chally (383m]

Has anybody experience with those Robertshaw HiFlow Thermostats?
"(..) thermostat features a large 1.5" orifice and a a balanced popit valve that opens smoothly with coolant flow, not against. Al brass and copper construction. When used with a Flow Kooler water pump, coolnat fow an be increased from 68 to 100 gph". That is a 47% increase of flow.
What to think of these devices?

[Henry (Henry)]

The following site has a lot of useful technical information on cooling:
www.stewartcomponents.com

Dave R had overheating probs on his car & they ended up being mostly down to an undersize rad (2 row instead 3). I think he now has a wide tube 2 row where before it had been a narrow tube set up.

Increasing waterflow is apparently a major aid to efficient cooling as it prevents the coolant saturating with heat in the block, therefore it will get to the rad at a lower temp which means the rad has less work to do.

First thing to do is make sure there are no blockages anywhere assuming everything is working to spec.

[Dave-R (Roppa440)]

Have a good read of the tech section at http://www.stewartcomponents.com/

I would say dump the flex fan. They do not work well. The stock mopar unit with the thermostatic clutch is much better. A correct fitting fan shroud makes it even better. Fit the biggest core possible in your radiator frame and use the Air Con version of the stock water pump. Buy a high output water pump from Summitt Racing if you have any problems. This one has the disc on the back and lots of huge blades.

One thing I found with my high flow water pump was that when I removed the thermostat my overheating problem got much worse. This was possibly due to cavatation around the pump blades because of the lack of resistance in the coolant flow without the thermostat.

[Dave-R (Roppa440)]

Oops! You jumped in there just in front of me mate.

My rad was a big tube two row but is now a big tube three row. Everything seems OK so far but we will see what it is like mid summer.

[Dave-R (Roppa440)]

Also I forgot to mention that a high performance electric fan mounted engine side of the radiator is another good option but try the clutch fan first. Much cheaper and more reliable.

[Robbert D 70`Chally (383m]

Well, got my radiator back. (And my tranny!) The core was not good enough to clean it, whater flow was blocked for 50%) Now I've got brand new one with 50% more capacity than a Calcium free original. (finer "net").

Also I bought a Fan shroud, original Mopar. It cost me 158 Euros. Now I am not sure whether I nevertheless would be better of installing an electric fan...

electric fan advantages:
+max capacity
+only on when needed, saving 18-20 horsepower
+saving whaterpump bearing

electric fan disadvantages:
-they suck 22-30 amps!!
-Price (I have the idea that freeing those 20 horses with an electric propellor is relatively cheap.)
-not original looks (bolt on => no problem with that)

If I would be sure that I would not get any charging trouble I would go for an electric option (and if the price would be acceptable, I am spending the equivalent of a state of the art computer on my car again this month)

I can't check my alternator right now, really don't know which one it is. (Standard version would have been 37 amps, optional were 50 or 60 amps).
Ok worst electrical situation would be a hot engine on a hot day followed by rain. Wipers (?amps), lights (aprox. 12 amps), heater motor (?amps, temporarily on), defogger (?amps, temporarily on). The LPG system consumes quite some too, I can find tomorrow how much that is. How many current do these consume together? (Not to mention the hifi with booster, but I rarely use it). I will check the alternator tomorrow.
Then I have to decide whether I ask the supplier to take back the shroud tomorrow, because my intention is to get the car on the road tomorrow night.

Anybody having battery charging trouble with your electric fans?
What is the best make, type (single vs double) and model electric fan? What do they cost? On a forum somebody mentioned the Spal 16", 2360cfm for 21.6 amps. I would want max cool and min amps off course. Dave, why did you make your own fanblades? Sigh, maybe I’ll stick to my mechanical fan and shroud…
Sorry if this post is confusing, I am very tired.

[Christer (Christer)]

I am very sceptic abot that 18-20 hp saving. To my knowledge this figure is somewhere around 5 hp.

[Dave-R (Roppa440)]

I did not make my own fan blades or fan. I only made the shroud. I am happy with my electric fan but what hp you gain from it not being mechanically driven is more than made up for in the hp lost having to drive the alt. harder.

I run my electric fan full time as the thermostat was damaged when the car overheated. They do fail on occasion for no apparent reason.

The mopar clutch fan is only on when needed too but is engine driven and can never fail. It is cheaper too I think esp. if you can find a second hand one.

[Robbert D 70`Chally (383m]

Thank you gentlemen, I will stick with the mechanical option for now.