I was sitting here in idle chit chat with my father..talking to him about getting an aftermarket hood, putting some form of fresh air system on it...

He asks "why"

Simply because my under hood temps are high. Cruising I dont have a problem...but idling, the temps starts to creak upwards....now I know what you are saying...they do get up to 200º...the problem is...is that sitting there idling...she can hit 250º-260º. My carbs are dialed in exactly where they need to be, did that by my wideband O-2 sensor. My timing is set up at 16º intial, my MSD has the black bushing (which is advertised as 18º) so I have 34º total. I have a MSD Timing advance when I first crank over the car so I get about 48º when starting and then backing her down to 0º on the controller, adjusting along the way if there is detonation (the fuel here is crap)

Anyways....he had an idea as to why my temps rise at idle....My transmission, 727, has the tranny line going to the radiator first, then it comes out of the radiator and goes to my B&M Tranny cooler, from the Auxiliary cooler it goes back to the transmission. Could the temperature of the tranny fluid be so hot that when it reaches my radiator its like a furnace and boiling all the engine coolant above?

I should point out I have a Gear Vendors behind my 727 and I normally just leave it in Auto Overdrive. I don't have a problem when I drive though, cruising along I am about 180º (I run a 160º thermostat) going 2500rpm at 75mph. So the engine isn't working hard to move the car.

Engine: 440, bored 30 over, HP Manifolds, Edelbrock 84cc, 4 core Chrysler radiator, SPAL 12" fan, No Air Conditioning, 7-blade fan with a viscous Clutch, CH-28 Edelbrock with Dual 500s.

Trans: 727 with a 2200 stall converter, Stock sump, Gear Vendors.

I have an Autometer Tranny gauge around here somewhere...Can I thread that into the 727 casing somewhere? Do I have to drain some fluid out in order to install that? Not as a permanent install but more of something to see what the 727 is operating at.

Thoughts?

It can't hurt to bypass the radiator altogether with the trans cooling lines. It sounds like you need a bigger radiator/fan. Is this engine >470 cubes?

sitting there idling you really aren't making a ton of heat even with a 2200rpm stall. If the trans is putting out enough to cause you to overheat then there is something wrong with the trans and it would be worse when driving .

Trans fluid temp should be checked from the output line going to the cooler. It will give you the best indication of the fluid temps passing through the tranny.

But Like John RR said it probably isn't your problem.

Do you have a fan shroud to direct the air through the radiator? If not you could be swirling air around the fan and not flowing enough through the radiator until your moving.

Do you have a spoiler to prevent air from recirculating itself from the back of the radiator around to the front? That is not usually a problem on old mopars with front valences but if the gap between the valence and the lower radiator is too big use something to make a barrier across the gap.

How good is the core? Is it clogging? Start it cold and let it run until the temp starts to rise enough to open the thermostat and check the front and back of the radiator for cool spots.

Does the pusher fan spin in the correct direction? Sounds simple but I have had more than one fan wired to blow the wrong direction.

Hope it helps.

A question just for clarity. Are you talking about under hood air temps or coolant temps?

I had my trans tempertature sending unit in the left front corner of the trans pan at first on my 1998 Ram 2500 CTD pickup, I switch to the little hole on top of the front servo because that is what the Turbo Deisel tech guys recommended, I didn't see any real differences in the temps I put the trans temp sender in the same location on my Duster, I never saw above 220 F when racing a very seldom saw above 180 F when crusing in the summer with the Duster with a high stall converter.It did not have the fluids going through the radaitor, small external coolor only The truck never got above 140 F when empty, summer or winter at or above 85 MPG getting on it around the corners and on the straight aways in the mountains of SO CA Hooking up the 24 Ft enclosed car trailer would make th trans temps go up to 160 to 190 during the summer at 65 MPH on the flats and go slightly above 220 F blasting up long hills at 70 MPH with the O.D. locked out Most conventional ATF will start to turn colors from red to brown at 275 F, it will go black above 325 F according to the Mopar drag seminar techs. years ago I would check the ATF temps before getting worried, most in the radaitor coolers are really warmers to help keep the ATF at or above 160 F My truck fluids would go really yucky looking real quickly when not towing Most ATF has additives in it that need to be at or above 160 F for them to work properly

largest trans cooler that will fit, different opinions if it should go before or after the rad bottom cooler. largest crank pulley/smallest WP pulley to speed up the WP/alt & an anticav plate on the WP. MP thermal clutch fan 1/2 way into a shroud. Plenty of rad which I believe you have. When idling #1 you need adequate airflow