Do all A bodies have overheating problems?

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bluefish1967

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I've owned a wide variety of muscle.cars, from Mustangs to Camaros to Challengers without any significant overheating problems..My current ride has frustrated me for years. After several different engines, and engine combinations over the years, one thing remains the same. If I idle for more than a couple of minutes, the engine temp starts creeping up. Not sure where or when it may stop, but I tested the car today after driving home in stop and go traffic. After 10 minutes of idling in Park the temp was up to 220 and still climbing.
My current combination is a fresh mostly stock 340, Weiand intake and Holley 570 street avenger carb, stock manifolds with duel exhaust, a Milodon high volume water pump and matching thermostat, a new 3 core U S Radiator( in place of the stock 2 core ), and a 6 blade fixed fan to replace the sock 4 blade. I also installed a new electronic distributor, and the vacuum advance is installed and working.
I can't believe these cars behaved this way when new. If moving down the road, the temp stays in the 180-185 range.
It appears that the heat cannot get out of the engine compartment. I noticed today when sitting in traffic, that heat was coming out from under the car when my hand was out the window. You can see the heat radiating off the hood.
I am confident of the tune ( timing and jetting ), the car starts, idles and accelerates beautifully. I just can't trust it to be stuck in traffic too long.
I tried a couple of years ago a generic 10 inch electric fan mounted behind the radiator pulling. It did not cover the radiator completely. It seemed to slow the overheating problem down, but it did not cure it. I'm thinking as a last resort a better electric fan system to help get the heat out from under the hood.
I would appreciate any help or advice, as I am seriously thinking about selling the car. Larry
 
bluefish1967 said:
I've owned a wide variety of muscle.cars, from Mustangs to Camaros to Challengers without any significant overheating problems..My current ride has frustrated me for years. After several different engines, and engine combinations over the years, one thing remains the same. If I idle for more than a couple of minutes, the engine temp starts creeping up. Not sure where or when it may stop, but I tested the car today after driving home in stop and go traffic. After 10 minutes of idling in Park the temp was up to 220 and still climbing.
My current combination is a fresh mostly stock 340, Weiand intake and Holley 570 street avenger carb, stock manifolds with duel exhaust, a Milodon high volume water pump and matching thermostat, a new 3 core U S Radiator( in place of the stock 2 core ), and a 6 blade fixed fan to replace the sock 4 blade. I also installed a new electronic distributor, and the vacuum advance is installed and working.
I can't believe these cars behaved this way when new. If moving down the road, the temp stays in the 180-185 range.
It appears that the heat cannot get out of the engine compartment. I noticed today when sitting in traffic, that heat was coming out from under the car when my hand was out the window. You can see the heat radiating off the hood.
I am confident of the tune ( timing and jetting ), the car starts, idles and accelerates beautifully. I just can't trust it to be stuck in traffic too long.
I tried a couple of years ago a generic 10 inch electric fan mounted behind the radiator pulling. It did not cover the radiator completely. It seemed to slow the overheating problem down, but it did not cure it. I'm thinking as a last resort a better electric fan system to help get the heat out from under the hood.
I would appreciate any help or advice, as I am seriously thinking about selling the car. Larry
Click to expand...

You didn't mention whether or not a shroud.
 
Your fan is the problem. It's that simple. If it cools cruising down the highway, the radiator is good. My "problem solver" is a factory flex fan. That usually cools anything at idle. I don't run shrouds either. If you don't like the flex fan, try an electric or clutch fan. I've run A Bodies as daily drivers for 40 years. They do not run hot. None but a very few were stock.
 
Everyone I've seen that posted about their A body running hot has been running one of them universal aftermarket fancy looking fans. Yet the guys running the stock ones don't seem to have near the issues
 
OLDMANMOPAR posted something interesting some time ago, and "it fits" what mine was doing. The original 273 "round tank" was in front of a 360, later a 318. It would overheat some worse on the highway. I was at a loss. A rad shop said "it flowed fine"

OldManMopar claimed that the thermal cycling over the years can crack the fins loose from some of the tubes. It can flow all the water in the world and won't "radiate."

I'm CERTAIN that was my problem. As a 'try this' I swapped in a two core slant six rad out of a later car and the change was immediate and enormous.
 
I run an aluminium Champion 3 core radiator in my small block Duster and it runs 180 degrees in July. Works great.
 
"thermalcycling over the years can crack the fins loose from some of the tubes."
Wow, that's something to think about right there.
 
nitroneal said:
You didn't mention whether or not a shroud.
Click to expand...
I"ve added a factory shroud. I've also tried a Mopar Performance factory style clutch fan and fan. Didn't seem to help.
When i purchased the car, it had a very sick 273 2bbl. Car would overheat anytime I idled in traffic when it was hot out. No factory shroud, 4 blade fixed fan. I just tried to not get stuck idling .
Then switched to a friends 318 4 bbl engine, when we upgraded his car to a 340. Never ran more the 195 in his car. Started having problems as soon as I installed it in my car.
Took the radiator to a radiator shop, they said it was 40% . clogged so they repaired it. No difference. That"s when I upgraded to a 3 core factory style radiator., along with a lot of other changes.
Now with a fresh 340, the problems persist. Today was the first time in hot traffic. I was OK with 190 or so in traffic, but the longer I putted around in traffic, the more the temp climbed.
I'm reluctant to try electric fans again for a variety of reasons. Maybe I need to look at a different type of fan blade.....Larry
 
Tune can cause over heating. What is your 340 build, timing total and advance and when. Carb and it a set up etc.
 
dano said:
Tune can cause over heating. What is your 340 build, timing total and advance and when. Carb and it a set up etc.
Click to expand...

Bingo.

You said you have had numerous old cars so you probably know your way around one. I'm not trying to be a jerk at all but you could have been making the same mistake the last xx amount of years. This could explain why it's been happening for so long and why it never happened with the same engine in your friends car. In my profession I see old timers that are doing something completely backwards but they have been doing it for so long that it is routine for them. What is your tune and engine details?
 
doogievlg said:
Bingo.

You said you have had numerous old cars so you probably know your way around one. I'm not trying to be a jerk at all but you could have been making the same mistake the last xx amount of years. This could explain why it's been happening for so long and why it never happened with the same engine in your friends car. In my profession I see old timers that are doing something completely backwards but they have been doing it for so long that it is routine for them. What is your tune and engine details?
Click to expand...
Agreed...that's why Im asking for help.


The engine is a stock bore 1968 340, with a stock 68 340 cam degreed in straight up ( .444 lift intake and exhaust). Carb is jetted slightly over base on primary , 56/65 jets, 8.5 power valve. Engine idles cleanly at 650 rpm in gear, 17 inches of vacuum at idle in nuetral. Base timing is 12 degrees initial, 36 degrees total without vacuum advance. Spark plugs are stock Champions, and are running clean. Larry
 
The only difference I can see ( and this is a stretch ) between this engine/setup from all of the other 273/318/340 engines I have had, is that the 67 Cuda radiator has the inlet and outlets on the same side. It has a different timing cover, with the degree marks on the passenger side. The water pump must exit on the drivers side.
When I installed the 318, then the 340 I had to swap on the 273 timing cover and water pump to make it work without changing radiators. Larry
 
Do you have the hood to radiator support rubber seal in place? Lots of times there discarded and not given a second thought.
 
Have u always used that high flow water pump on all the engines? I've heard that pushing too much water too quickly thru the rad does not allow it to cool enough.
 
Okay. Similar set up. 340 six pack in barracuda. Same problem in traffic. Same timing. Cam 528/528 solid lifter cam. My over heating solution. Griffin 2 core. Two cores are 1.25" wide. Hayden short fan clutch with viscious fan. 5 blade. Aluminum fan shroud. Two 10" electric fans mounted on the front as pushers. I only need to turn the fans on in traffic. Now the fans will not lower the temp in traffic but the temp does not climb. I also have a trans and oil coolers as well. Hope this helps.
 
The water pump could be pulling too much volume thru the radiator and collapsing the lower rad hose creating a starvation issue ='Increased heat
Be sure the lower hose is good and has the internal spring in perfect condition
 
If it works over 30 mph, then the cooling system is adequate.Your problem is all in the moving air thru the rad when stopped or under 30 mph. That points squarely at the fan,it's drive ratio,the shroud, and . with a possible aggravation if the carb is sucking hot underhood air.

I run;
The fan I use is a 7-blade hi-attack unit off a 73 Dart 318 with A/C. The blades are the biggest widest most pitched I have ever seen. I run it with a thermostatic clutch,( NOT the Mopar viscous coupler) off an early 2000s F150. And I run the 73 shroud, with the fan well into it. I run a slight underdrive ratio on mine cuz I wind it out to 7000 all the time.I run 50/50 antifreeze.And I moved the front Liscence plate way over to one side, and removed the OEM plate bracket(68 Barracuda.) I also run that same 1973 A/C Dart rad. Hyup,44 years old this year.And I run fresh cold air into the 750DP.With these parts installed, my approximate 420 hp 367 runs a solid 205 all the time. I am so confident in the system that I run a 7 psi cap, and have since 2002ish
>I had no luck with the OEM type 6 narrow-blade fan nor the 5 blader with the very wide blades, nor a flex-fan that I tried (that was the worst).

IMO;Your timings are fine, and so is the hi-flo pump/stat (I run those same items).
Have you verified your gauge readings with an IR gun?
You're not running an A/C condenser up front are you?

I had a 69 340-4gear FormulaS, with the totally stock cooling system. It ran fine.As did my 74 DartSport 360 4-gear.And my 70 Swinger340-4 gear. And every other Mopar I ever had, since 1970. The factory systems always got the job done.
So, please don't put all Mopes into the same category as your unit.
 
pa340dart said:
The water pump could be pulling too much volume thru the radiator and collapsing the lower rad hose creating a starvation issue ='Increased heat
Be sure the lower hose is good and has the internal spring in perfect condition
Click to expand...

Good advice, but his problem is at idle and at low speeds in traffic. He did not mention a problem when running hard.
 
Even when my car was running high 11s in the 1/4 with its original, non stroked, 340, it could idle until it ran out of gas on a 100 degree day without overheating.

Most cooling problems are owner caused by trying to reinvent the wheel.

My secret..... 100% stock cooling system for an AC equipped car with all components in place.

This is the cam in running, not that it really matters.

Voodoo Solid Roller Cam - Chrysler 273-360 273/279 - Lunati Power
 
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check your belts, that thay not setting way down in the pully riding the bottom side slipping threw the pullys! seen it happen when wrong spec belts used or pullys wore out, it rare but happens! might try a different thermostat, i like the ones that stay open when thay fail. my 71 340 duster with stock radiator high compression over cammed over carb'ed threw stock manifolds with no shrowd and a flex fan never got above 185/190 stop n go 100 degree days...over 10 years never a issue,dont even think it had a thermostat, never even looked....DWB
 
Yote said:
Unless I missed it , what thermostat are you using (temp rating) ?
Yote
Click to expand...

I'm using the Milidon high flow thermostat that was recommended with the Milidon high volume water pump. I believe the thermostat was rated at 185.
I agree about moving water too quickly through the radiator, but the problem was there using the stock water pump and 180 thermostat. I've considered putting a stock thermostat back in.
The lower hose is not collapsing, it has the coiled wire in it and is firm when the engine is running.
I am running electric Accumeter gauges, but have checked the temps with an IR gun. Yesterday, the upper hose was showing 221 degrees, the lower showing 210 after idling for 15 minutes.
Agreed, the open element air cleaner makes it worse.
I've owned this car for 14 years, and thought recently that I had finally turned the corner. At this point, I really don't know what to try other than a different style of fan blade....Larry
 
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