typical partly plug rad will show up at higher RPM's (eng producing more heat/rad cant keep up). I'm trying to decipher what is changing but nothing is jumping out at me. You're sure nothing has been changed/altered? It ain't making sense (but we love the toughies!). If it was OK WO a shroud then it oughta stay that way but SOMETHING is slowly changing/deteriorating & that is what we need to figure out. The cooling system will hold psi when hot/set overnight?

http://www.brewersperformance.com/proddetail.php?prod=RAD-SHR423

No, all 22" fan shrouds are not the same.

It might be the Hayden #2765 that is 2.67" long. EDIT & the cooling psi holding I was thinking of a potential slightly increasing head gasket leak. (& it may be as simple as the rad). I would want it at 185 or above with a confirmed accurate gauge.

http://www.brewersperformance.com/proddetail.php?prod=RAD-SHR423

No, all 22" fan shrouds are not the same.

You should also remember that in 70the lower outlet changed. If you are running an aluminum water pump then it's the later style, if you are running an iron water pump it's the early style,

If you are indeed running the later A body radiator like you think then

https://www.classicindustries.com/product/1972/dodge/dart/parts/ma2228.html

No, all 22" shrouds are not the same. You will need to know what the radiator was designed to fit to get the application for the shroud. And the clutch is a good idea, it reduces drag on the engine, but it will not do anything for the over temp issue you are experiencing. Your '65 did not come with one and it cooled fine then.

A good rule of thumb that we have always used to help solve over temp problems is; over temp only at slow vehicle speeds is usually an air flow issue, while road speed only over temp issues are usually water flow related. Now that is a very general statement, but does help narrow down the problem most of the time.

So, since your car controls it's temp at road speed, it is probably getting enough water circulating. At least at higher than idle engine speed. But it is possible that there is not enough water circulation at idle. Mopar used a number of different sized pulleys on the crank and water pump so different pulleys can be used to vary the water pump/ fan speed at idle. A quick test you can run is to set the idle up 300 RPM or so and see if that helps at all with the over temp.

And before you pull the radiator to have it cleaned, you can take a temp gun and go across the radiator when the engine is up to temp. If the temps are consistent across it, then you don't have any significant blockage. If the radiator has blockages, you will have much warmer and cooler areas. Then there's the fact that it cools going down the road which indicates that the water flow is at least adequate. But remember that the air flow through the radiator does increase substantially at road speed.

Next, how close is your fan to your radiator? A shroud is a very good idea and may end up being necessary, but having the fan close enough to the radiator might do the trick too. Then there's the fan itself. How much air does it move? If you do go to a clutch, you will need a different fan for it. And it will need to match the shroud, if you get one.

Thanks Dave a lot of good troubleshooting ideas hear.

Fan is about 1.5 to 2” from the radiator.

Have tried multiple fans no change.

I have a mopar clutch fan in the box but the clutch is too deep.


Can you post a picture or two of your fan/radiator so we can see what you have?

typical partly plug rad will show up at higher RPM's (eng producing more heat/rad cant keep up). I'm trying to decipher what is changing but nothing is jumping out at me. You're sure nothing has been changed/altered? It ain't making sense (but we love the toughies!). If it was OK WO a shroud then it oughta stay that way but SOMETHING is slowly changing/deteriorating & that is what we need to figure out. The cooling system will hold psi when hot/set overnight?

Partly plugged rad can show up at idle also, my 67 Charger always got hot in traffic, parades, in and out of heavy car show parking, had rad re-cored last spring, last year coming out of Moparfest, in line for almost 1 hour, never got over 185 on a 90 degree day.