Hi Fellas, New here and looking for a little input. I am in Arizona. I have a '66 Nova with the L-79 350hp 327 4 speed. It is a fun little car and basically stock. I have added a new aluminum radiator and it has a good fan clutch with the correct fan shroud in place. My problem is, because of the high ambient temps the cars still heats up easily in stop and go traffic or on very hot days. Doesn't boil over but gets up to the red zone if I don't shut it down. Gauge is accurate. If temps are down in the 80's or lower, I never have a problem. I added a 14" electric fan which I use on very hot days and this helps but doesn't solve the issue. My question is this, if I were to expand my cooling system by, say two gallons, perhaps by tapping into the heater hoses and adding a reservoir of some type for the additional 2 gallons, which would be approximately 50% more coolant, do you think this increase in coolant would abate the heating problem? Thanks, Ronnie
Nope. You need more cooling surface, and/or more air moving over it. All adding cooling system capacity will do is create a larger m*** to heat up, so it will take a little longer to get it too hot. It will then be even harder to cool it off.
Do you know how it it is when it gets to the "red zone"? 230 is ok, over 240 is too hot (for me). Boiling happens around 260 if you have a pressure cap and 50% antifreeze. If it's not boiling, it might be OK...kind of depends on the engine. Yeah, I have Chevy II with more engine than radiator, so I'm familiar with the problem.
A lot of time the radiator is big enough but the airflow is stagnant. You might have a larg enough opening in front of the radiator but no place for the air to escape the engine compartment. I've gotten by a few times by adding a small air dam directly under the radiator. I've gotten by with a 2" dam pointing straight down, what this does is create a vacuum at the back side of the radiator helping airflow.
Desperate conditions call for desperate measures - an auxiliary water cooler. <stand by for flack from folks that live where summer is a couple of months of poor ice fishing...> Derale # 15945 auxiliary cooler - Running coolant through it instead of oil. Bosch 392 020 073 Electric coolant pump Electric solenoid to raise the idle while sitting in traffic (higher idle pulls more air thru the radiator and circulates the coolant faster). Standard ES9 (Chevy 1968 - 1988, etc.) Notes: 1. This is an in-progress photo - Wiring not yet .completed. 2. Picture shows a home-made aluminum bracket. Engine vibrations snapped this bracket, I made a replacement bracket from steel. 3. Added Red Line Water Wetter - Sort of works, slowed the temperature climb when parked, idling and AC running. 4. Added insulation (header wrap) on the header and the exhaust pipe. 5. 6 blade fan. 6. Insulated fuel lines. 7. Home-made aluminum heat shield and insulating spacer under the carb. 8. WIX-33040 fuel filter at he highest point under the hood. Has a fuel return to bleed off the vaporized gas. Buick 1963-1967 and many other makes. Russ
What he said^^^! What's the size of you aluminum radiator? Is it a 2 row, 3 row? Which thermostat are you running? Is the 14" electric fan a pusher fan to support your clutch fan? Is the radiator a closed system where it recirculates or does it just dump into an overflow bottle? In the Arizona heat you need superior airflow. Clutch fans are good but I'd say find the biggest, baddest, most CFM electric puller fan you can find, mount it and see what happens. Derale makes a monster 2400 cfm fan............. https://www.summitracing.com/parts/...MIl9qU2JK88QIVuHxvBB0LVQeAEAQYBiABEgKpGfD_BwE If you wanna go the cheaper route, check your local Pick-N-Pull. I found this monster on an '89 T-Bird Super Coupe. Slapped it into my OT '89 Mustang. Not sure of the cfm but the price couldn't be beat. $12.50 on Pick-N-Pulls half price day!
I have to agree that air flow is at the top of the list. Not all electric fans are created equal and you can have two fans that are the same size and look the same and one will move twice the air as the other one. If you check the Spal fan selection page there are huge air flow differences between fans the same diameter.
Not just low, as wide as possible as well. This creates a pressure differential across the radiator, high pressure in front, low in back so the air will want to naturally flow through the radiator. Build that wall, make cooling great again.™ You will also want to verify that that radiator is sealed fairly well around to the radiator support. Air should be going through the radiator and not spilling around it. Sometimes a little ducting will greatly improve cooling ability. Use some cardstock(cereal box) and duct tape to seal around the radiator. And plug up any unused large holes that are in the radiator support. Air will find the path of least resistance. If too much air gets into the engine compartment that is not being utilized for cooling, it can pressurize the engine compartment and actually have hot air pushing back out through the radiator which will reduce cooling and cause overheating. Air should go around the car or be ducted to aid in cooling. Anything else is just drag on the car and can cause lift.
so what does the temperature do after shutting it down, and the coolant stops moving, - does it go up or does it go down ?
Ignition advance on idle? Ported or manifold vacuum? Supposed to make a difference in how much heat the engine produces on idle - and as it seems to be when you have the issues it's worth investigating.
Everybody's first thought is toward air movement, and I'm not saying that's wrong, but you also need movement of the coolant. We've talked about this many times before around here, but speeding up the water pump will help. The more the coolant circulates, the more heat it will transfer from the engine to the atmosphere. Check your pulley sizes, if the water pump pulley is smaller diameter than the crank pulley it will be overdriven, and if the ratio is flipped so the water pump pulley is larger it will be underdriven. You want it to be overdriven. There are various diameter pulleys available. There are also pumps with greater pumping capacity available for this reason. p.s. ignore the guys that say you need to slow the circulation down....
I would start by flushing the block and cooling system. Rust and sludge in the water jackets impede cooling. People want to start with electric fans and aluminum radiators when they have an over heating problem, but never flush the cooling systems. That's like putting new shingles over the old shingles on a leaking roof you didn't fix the problem, just patched it. Don't forget it has always been hot in Arizona and L-79 were sold new there then just as now people would not have tolerated their new cars overheating.
Just thinking out loud, an engine oil cooler can take 10* out of the engine. I would get an infrared temp device and verifie temps.
When the '68 Corvettes came out, they had an over heating problem that Chevrolet solved with an air dam.
I had the same issue with my hotrod....Ended up replacing the 4 row br*** radiator with half inch tubes which was a triple flow from US Radiator to a 2 row aluminum radiator with inch and half tubes...Cured my issue....
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