Overheating has ME overheated!! 2nd Electric fan(s), I think it's not the fan or radiator

[Dan64]

^^^ I do like the Derale shrouds with the rubber flap "Air letter outers" ,lol, which help stop the air flow from deadheading in the shroud at speed. I used the Derale with twin Spal fans for that reason over the C.C shroud set up. you could always modify an existing shroud ,it's only rubber and some screws.

 

[Dan64]

You know they never overheated when new with all O.E.M. equipment,even with a 30"x 8" grille opening,this has never been over 200* under any condition,idle,on the road or whatever !

View attachment 1006912

Your right but once you start getting into stroker motors and more race type stuff it's a whole new ball game ( and a rabbit hole).

 

[Dan64]

Agreed on the spring, especially if you decrease the clearance on the water pump impeller, as that will create more coolant flow, and increase suction on that lower hose, and that could become a new culprit if it isn't already.

But if you are not actually boiling coolant out, I would disregard the radiator cap as a cause. The cap maintains a pressure rating, which raises the boiling point, but doesn't change hte coolant temperature. Increasing the cap rating also increases pressure on your heater core. I always want the lowest pressure cap required to prevent boiling.

I've always been told that a bad cap can cause a vacuum problem which can make the lower hose collapse?.

 

[Fury Fan]

Your right but once you start getting into stroker motors and more race type stuff it's a whole new ball game ( and a rabbit hole).

And that can cause aftermarket parts that get good reviews in run-of-the-mill installations to not work well on the edge.
Or a combination of good parts that doesn't work well together.

 

[Fury Fan]

I've always been told that a bad cap can cause a vacuum problem which can make the lower hose collapse?.

I've not heard that before, but I surely don't know everything.
But I would think the head pressure of coolant above the lower hose would make a cap located physically higher irrelevant vs the lower hose? And if the cap wasn't sealing well, atmospheric pressure would actually help push coolant into the lower hose?

As I think of this some more, perhaps a bad cap could allow air into the coolant, which could entrain down to the lower hose, and then those bubble collapse under teh suction, which would cause the hose to collapse. But that would seem to need a lot of bubbles to cause that?

But regardless, any suction hose needs to not collapse, and a spring is a fine way to assist with that.

 

[Lionized]

FYI; the spring in the lower rad hose is there from the factory to install the coolant. It serves no other purpose than to prevent the hose from collapsing during the factory installation of coolant as they used a high pressure vacuum to draw coolant through the system. After that, it's useless. If your system is collapsing the lower rad hose you have other problems.

My cooling system issues were due to the PO installing an under-drive pulley on the crank. At low speed/idle in traffic I could watch the temps climb and it took me a lot of trial and error to source the issue. No problems since replacing that pulley with a factory reproduction.
Something to consider.

 

[Dan64]

FYI; the spring in the lower rad hose is there from the factory to install the coolant. It serves no other purpose than to prevent the hose from collapsing during the factory installation of coolant as they used a high pressure vacuum to draw coolant through the system. After that, it's useless. If your system is collapsing the lower rad hose you have other problems.

My cooling system issues were due to the PO installing an under-drive pulley on the crank. At low speed/idle in traffic I could watch the temps climb and it took me a lot of trial and error to source the issue. No problems since replacing that pulley with a factory reproduction.
Something to consider.

I was wondering if the CVF for the Pontiac was using a pulley that was too large making the system cavitate as speeds?. Hoping for something simple so Bio can get as least one of his rides to Cruizin the Coast.

 

[biomedtechguy]

Does your setup look comparable to this one?
View attachment 1006913

The 1st fan setup I got from Cold Case, the radiator manufacturer, was a dual 12" fans and aluminum shroud assembly, but the cutout openings for the fans made up a much larger area that the one pictured.
Here is the dual 12" shroud:

Here's the 16" two speed single fan shroud, 4.9 out of 5 stars, 70+ reviews, and my vendor SWEARS by them:

The reason why they are off the car is because the dual fans are going back regardless, I already have a RMA for the return and I have my doubts as to the quality of the fans themselves. (I still can't believe they'd sell a product that doesn't work though). The 16" fan is off because I just put the factory mechanical clutch fan back on, the factory shroud will NOT fit because the CVF Wraptor serpentine belt and accessories system pushed everything too far forward making the shroud enclose too much of the fan for effective cooling. I'm about to refill the cooling system again, drive it on the highway, and if it doesn't overheat, I'm going to carve up the factory shroud to make it work with the mechanical clutch fan, and tear my vendor a new *** if I can't get a full refund on the 16" fan.
Honestly, I'm also trying it because the next step is removing all of the Wraptor stuff that is in the way of getting the water pump apart, and that's going to SUCK, but it will be my next move. I may see if I can find or make a spring for the lower hose first, and try that.

 

[wagonman]

Got a buddy with a 71 Buick Skylark with a 455, he had low speed cooling issues. I told him to bring it over and I will take a look. Turns out the solid flex fan was on backwards. DOH. Never say never.

 

[biomedtechguy]

FYI; the spring in the lower rad hose is there from the factory to install the coolant. It serves no other purpose than to prevent the hose from collapsing during the factory installation of coolant as they used a high pressure vacuum to draw coolant through the system. After that, it's useless. If your system is collapsing the lower rad hose you have other problems.

My cooling system issues were due to the PO installing an under-drive pulley on the crank. At low speed/idle in traffic I could watch the temps climb and it took me a lot of trial and error to source the issue. No problems since replacing that pulley with a factory reproduction.
Something to consider.

THANKS! That is a HUGE help regarding the spring!

The water pump from CVF is high flow and well made. That is not the problem.

 

[biomedtechguy]

I was wondering if the CVF for the Pontiac was using a pulley that was too large making the system cavitate as speeds?. Hoping for something simple so Bio can get as least one of his rides to Cruizin the Coast.

IF that was happening from the high flow pump, it would point to the gap being too big between the water pump impeller vanes and the divider plate. That is what I fear is the problem, because my installer on that job f'd up!

 

[biomedtechguy]

The cap is 16 pounds. The new thermostat is a high end Stant.

 

[Lionized]

I was wondering if the CVF for the Pontiac was using a pulley that was too large making the system cavitate as speeds?. Hoping for something simple so Bio can get as least one of his rides to Cruizin the Coast.

That could also be a possibility. You would like to believe these systems are engineered properly but you never know.

 

[biomedtechguy]

I'm going to refill the cooling system right now, and go drive on the highway.
Stand by for the next report.
The assho...I mean mechanic who did this work is coming by tomorrow to address some other issues, like the Dakota Digital dash light dimming or going out (it's bright daylight so I can't tell which is happening, but neither should) and explain to me how the AC levers are supposed to work. Right now, with both levers to the left (temp and choice of vents) I turn the fan on and the AC comes on. I need a refresher on what the damn horizontal levers do. I assume one changes the temperature, but I'd like to know if the other one makes the defroster work. Also, the AC compressor stays on with the temperature set to warm, and if the other lever is moved to "Heater" or whatever (my brain is mush) the damn AC compressor should NOT engage.
I hate having someone work on our cars, but at least the guy doing my Roadrunner is knowledgeable and trustworthy, and he is labeling the wires he's connecting to the Dakota Digital block and other stuff in my car so if I have to do something I know what is what. It's a good thing too, because OMG:

 

[493 Mike]

I bought this 22" for my 65 Belvedere from Wizard. I told them the horse power and they designed a system to cool. I hope it works! Might have the car assembled next summer.
Mike

 

[69b3rt]

What temp is the ideal running temp? Most electric fans on newer cars turn on at about 230-240 degrees and cools down to about 200-210 and shuts off. The radiator cap has to work correctly to hold the pressure to keep boiling point down.

 

[Dan64]

I bought this 22" for my 65 Belvedere from Wizard. I told them the horse power and they designed a system to cool. I hope it works! Might have the car assembled next summer.
Mike
View attachment 1007003

Mike, are you using a later k member in your 65'?

 

[Fury Fan]

The 1st fan setup I got from Cold Case, the radiator manufacturer, was a dual 12" fans and aluminum shroud assembly, but the cutout openings for the fans made up a much larger area that the one pictured.
Here is the dual 12" shroud:
View attachment 1006998
Here's the 16" two speed single fan shroud, 4.9 out of 5 stars, 70+ reviews, and my vendor SWEARS by them:
View attachment 1007001

Vs the picture I posted earlier - your box shroud, even for the 2 larger fans, is still blocking a lot of air, and the single 16" is even worse.

If the shrouds were deeper and funnel-shaped toward the fans it would help, but as-is there's gonna be a lot of trapped air in those corners.

The hub on that 16" fan is pretty huge, too.

All that will start to back up airflow out front of the radiator, esp if you are missing any factory seals that help cover gaps and force air thru teh radiator core.

Those will surely get high-star ratings from lower-HP guys that are running hot at idle, but IMO those shrouds are part of your problem. The one 493Mike showed is a better idea - each fan is shrouded individually to improve its performance, without blocking core airflow. A fan array actually needs to be shrouded like that, individually, to keep stress and noise down as the neighboring fan tips head toward each other. Each fan must be 'fenced in' and isolated from its neighbors.

BTW - is this car an auto-trans, do you have a large aux trans cooler in front of your radiator?

 

[Fury Fan]

FYI; the spring in the lower rad hose is there from the factory to install the coolant. It serves no other purpose than to prevent the hose from collapsing during the factory installation of coolant as they used a high pressure vacuum to draw coolant through the system. After that, it's useless. If your system is collapsing the lower rad hose you have other problems.

I've bought replacement hoses that have the spring in them, why would they include it then?

 

[coloradodave]

Bio, I recently replaced my Mopar 18" 7 blade fan and matching factory shroud with a dual electric fan/shroud set-up from Summit; https://www.summitracing.com/parts/sum-g4850. I have a Flow Kooler pump, a 190* Stant thermostat and a Griffin 26" radiator with 2 - 1.25" rows of tubes. I use 2 - 30 amp relays. 1 fan is wired to a 190* sender and the other fan is started by my Fitech EFI control, which is set at 200*.
Our temperatures here in Northern California have been hotter than normal this year; we have had 3 week stretches over 100* (up to 112*) and I drive my car a lot. I've found that both the mechanical fan and the electric fan set-ups work equally well for me. The car runs at 190-195* while driving. At idle, such as a long signal, it will increase to 205-210*.
I am very happy with the electric fans. I tried the Derale set-up, but, like your car, there wasn't enough room for the depth of the unit. Hope you get your car figured out so you can attend your event...