Need to stop overheating

[AmadeusCharger500]

I thought I posted this question but it seems to have dissappeared, if not I do apologize.
My car has been running hot during city driving in the summer, which now inlcudes spring and fall it seems. Anytime the outside temp gets above 85, It creeps up to 200 then 210 and sometimes as high as 220.
I have tried so many things I can't even remember all. Radiator has been flushed and tested, clutch fan added with a spacer to bring it closer to radiator. Its a rebuilt 383 with 2500 stall with trans cooler, 3.55 gears.

I tried purging the water system of air but that didn't do anything. I've tried the special water wetter stuff too.

The car has never actually boiled over but it makes for a nerve racking drive when I get in traffic, and since I want to take it to Carlisle, hottest damn week of the year, then I'd really like to fix this.

Barring the chance the water passages are plugged, thanks rebuild, I am willing to try anything. Do I need a new radiator?

[oldcarnut]

A few things to mention but you probably already checked.
*Does it have a fan shroud on the radiator.
*What kind of fan are you using?
*Lower radiator hose with spring inside.  Hose may collapse without one slowing coolant flow as you drive.
*Thermostat.  Is it opening all the way and what temp is set for?
*Water pump ok?
*Radiator was flushed and tested.  I had one on my Challenger that was tested and they said it was ok.  I went through the entire coolant system because of similar problem replacing everything step by step except the radiator but no help.  Put on a new one and it fixed it. 
*Temperature sending unit.  Is it accurate or has it ever been replaced?
*On my R/T with a non stock 440 I installed a push fan to compliment the regular fan with a thermostat switch to come on and shut off about 195 for heavy summer traffic.  Works good for me as it only comes on when a little extra air is needed and will run a little after shutting the car off for heat build up.
Good luck

[AmadeusCharger500]

Shroud yes, new milodon water pump and thermostat set for 180. I think its opening good. AFtermarket temp guage I can only assume its working since it conistently says 180 in normal driving. I have an electic fan I added but it seems to have died. I would like to know more about yours, brand and how you mounted it. Mine I had to install a switch to turn on and off.
So thats interesting about the radiator!

[3--Daytona]

You more than likely need a new core, the core is heart of  any cooling system.   A homemade way to test your core,,,,Remove lower rad,, hose,hold your hand over rad, opening, have someone fill full of water, when full of water, move your hand, water should "gush" out in 2 1/2 to 3 secends, if it takes longer, core is marginal.      3--daytona

[1969chargerrtse]

I've always found these cars to run a bit hot. My 440 is like yours as it gets hotter as the temp of the day goes up. There are some things you can do as listed but it just doesn't sound like it's really something to be over concerned about. When I go to shows the Mopars always seem to be border line over heating. The push fan sounds like something I may look into.  I run about a 1/4 up the gauge in cool weather and 1/2 way up in hot weather.

[68 RT]

If it only does it in stop and go traffic it is an air flow issue. Try going back to a stock 7 blade non clutch fan. My 440 rarely gets above 210 even in stop and go traffic. I have 22" 3core rad. no shroud, 160 deg t stat, milidon high flw aluminum water pump, ans stock 7 blade non clutch fan. 

[W4ATL]

Try going back to a stock 7 blade non clutch fan.

Do you have a source for a non clutch fan? I am having some overheating problems and the fan I have you can spin it no problem when it is hot.

[bull]

Is this the stock, two-row radiator? If so those were never good at cooling these engines. Just to remove that from the equasion I would probably either get an aftermarket aluminum radiator or have the core on your original replaced with a 3- or 4-row.

[flyinlow]

Just to clairify; starts warming up in traffic, run 180 deg on the road.

I would suspect an air flow problem. There are 2 types of clutch fans. Centrifical, which runs the fan alot at low engine speeds ,but freewheels at higher engine speeds. Theromstatic clutch lets the fan loaf along untill the air coming thru the radiator gets hot enough to heat the bimetal spring on the front of the clutch and direct the silicone oil inthe clutch to drive the fan at a high rate aidding in cooling in traffic. Thermostatic clutch is better and costs more. This type of clutch will make the fan roar in traffic on a hot day,assumming you can hear it over your exhuast.

The electric fan you installed . Is it infront of the radiator? Is it a pusher?

A simple switch will work. I use relays on my fans. They Come on with a thermostat in the radiator when warm or if I turn on a switch.   

[oldcarnut]

Here's my fan setup.  Fan is a pusher,  Thermostat came from Autozone.  I set it to come on around 195-200 and it will stay on after I shut it off  until the temp comes down.  Usually not much more than a couple minutes or so. Works good for me.

[oldcarnut]

Thermostat

[oldcarnut]

Inside shroud

[2Gunz]

Find an el cheapo aluminum radiator on ebay for a couple hundred bucks.

Thats what I did when I started having trouble.

Problem solved.

[AmadeusCharger500]

Yes fan is in front of radiator just like oldcarnut, in fact it looks almost the same but mine is hooked up to a switch on the console.
So how do I tell if my engine fan is Centrifugal or thermostatic. I got at least 3 different clutch fans from junk yards and just picked the one looked nicest for cleaning and painting.

Radiator is a 3 row recored about 10k miles ago.

Hey oldcarnut how do you have that thing attached to the radiator?

[Purple440]

I used to overheat around 220 until I realized my timing was way too low.  Your's probably isn't that bad, just my 

200-210 doesn't seem that bad, I hit that on hot days in the summer sometimes.

- Doug

[flyinlow]

The thermostatic clutches have a coiled bimetal spring in the center on the front where it can sense air temp coming thru the radiator.

Is used on a/c cars or hd cooling. Used with a steel fixed pitch fan ...5,6,0r 7 blades. Do not bolt a lightweight or flex fan to it. used in conjunction with a fan shroud.

When radiator is cool and the engine is running it only ports some of the silicone oil in the clutch to drive the fan saving power,noise,and gas milage.

When the radiator gets hot and the engine is running it ports all of the silicone oil to drive the fan at high speed ( uses a smaller pulley to overdrive the fan) when this is occurring the fan is noisy. It sound like a truck engine with alot of fan noise.

If the fan clutch has sat drive side down the fluid can leak out rendering the clutch ineffective. old age and loss of fluid can cuase the same thing.

[oldcarnut]

Yes fan is in front of radiator just like oldcarnut, in fact it looks almost the same but mine is hooked up to a switch on the console.
Hey oldcarnut how do you have that thing attached to the radiator?

Which thing are you referring too?

[AmadeusCharger500]

I was wondering how you attached the electric fan to the radiator. I have mine rigged with plastic ties fed through the fins and metal washers keep them from pulling through.

[oldcarnut]

Mine is attached about the same way only the ties are made for attaching fans and not the regular cable type ties.  You can see one of them between the blades and in front where it comes out thorough the fan mount grommet.