Five Oh

So I guess the general consensus is upgrade the fans? How do I check to make sure the water pump is actually pumping? Only other thing I can think of is the almost 40 year old gauge...

The13Bats

I do not know what the general consensus is, if your car overheats at idle it's likely air flow IF it cools while driving,

I went to electric fans because I modify everything, almost,

I wanted the look of it I also had to upgrade my alternators and wiring,

The factory shroud and clutch fan will cool a c3 and even more so with the nice big aftermarket radiator you have...if it didn't cool with the factory shroud and fan something is wrong...is air leaking where the shroud meets the radiator is the clutch not locking up?

augiedoggy

The point I was expressing here was the rad is fine but the fans (which perform the function of cooling the rad surface and antifreeze in turn) are not enough to do their job when the car sits in the driveway idling for long periods. This is not the fault of the rad being too small although a larger one would provide more cooling surface directly in the fans path and help.

waterpumps do fail... The one in my old boat was barely trickling. if your cooling system was mistrteated and your old rad was a mess theres a good chance your water pump prop could be badly corroded.

depending on the year of the car the lower air deflector is very helpful and inmproving air flow... There is a thread here somewhere when one of engineering types actually took temp and time measurements with and without it and reported they have a large impact on them.

I dont have my side rad seals in my car and have no issues so I would agree they are not always needed but they have to help from and engineering standpoint and my rad is overkill for my setup.

augiedoggy

How about the sending unit for the temp gauge on the head? it is the original one right? they are all different and the universal ones will read waay off in temp. I had to mount mine in my intake when installing dart heads because the threads are too large for many aftermarket heads..

The13Bats

Every forum has the guys boasting about their engineering degrees,
again no argument on the stuff being there for a reason on a bone stock car, The factory did all that because they had to it did cost them money they wanted to save, however, when people run oversized aftermarket radiators and big fans things get more forgiving or even unnecessary...if I was running a stock factory radiator I would worry far more about each and every seal.



I have often wondered just how good was the stock temp gauge and sender when new, and now they are old, if 10 were tested how much would their readouts vary even though they were all in the same temperature,

While a bit jalopy or steampunk I have always placed a good and tested to be accurate temp gauge right in the intake or head, while I know if we split hairs even the sensor position can show different temps I still like a temp gauge right there on the engine, then at a glance while tuning or whatever I can see the temp....tech has caught up and those laser temp guns are pretty cheap at import tool fright but I still do mine old school.

augiedoggy

I'm not really sure twehat you meant there,
I dont think I ever mentioned anything about engineering degrees? I was saying that it logically made sense from an engineering standpoint.. You only need common sense not necessarily any degree to understand forcing more air through the rad is better than around it. again I agree its not needed but can help as you said.

I simply commented from my experiences on the subject since thats all I have as far as knowledge on this matter. I dont recall trying to be argumentative or discredit people either.
As far as the sending units, They have specific ohm values and if you use a generic one that is not the same value as the one for your year car you would be waay off in temp readings. I realize they all very a bit even when new but I'm talking way out like as much as 30 40 degrees. You can do a search here and find it actually happens a lot. I thought it was an issue with my uncles car until I used a temp gun to verify things.

As far as the water pump.... Its my understanding the op has had these issues since he bought the car so whos to say it wasnt a gradual thing before he bought it?

Five Oh

Y'all aren't going to believe this ****... I was taking the two 12" fans off to replace with a 16" fan with more cfm and somehow damaged the radiator removing the fan from the push through clip that holds it on. It's freaking leaking now! I want to throw up...

SH-60B

Yeah I never did like the idea of that mounting option, for that exact reason.

0Tom@Dewitt

I totally disagree

95 customers out of 100 solve this issue by putting the vacuum can back on the distributor. I have un-sold many radiators by suggesting this first.

https://cdn.shopify.com/s/files/1/01...52338609142409

The13Bats

my bad

I had no idea that you kill 95% of potential sales due to c3's that do not have a vacuum can on their distributor.

I didn't realize so many people didn't use vacuum cans on a c3 street car and have the can removed from their distributors and sure missed where they OP posted he has removed his,

Many thanks for clueing me in, setting me straight and solving his cooling problems....




Five oh, man when I read that it sprang a leak I felt your pain I believe we have all had something craptastic like that happen to us and it sucks out loud.
All is not lost, Champion just might stand behind it so ask them and if they won't then a good radiator shop can weld up that leak,

I do not like the zip tie style fan mounts for just this and other reasons

cooper9811

Doesn't matter what radiator you buy, the zip tie mounts are risky IMO. When I bought my 79, the PO had installed a small (unnecessary) fan in font of the stock fan (on a stock rad) to help cooling. It was zip tied and sprang a leak when I removed it.

Timing could be an issue, so it certainly can't hurt to make sure your timing is not retarded - that could be a cheap fix. And it's always a good idea to know what you timing is for other reasons.

However, given the relatively low airflow numbers you quoted earlier in the thread, I would lean towards needing better fans - 1700 cfm total seems low. I would look into going to the stock fan or stronger electric. I would stand behind Bats' statement that hot at idle but cool while driving is a clue that is supportive of this conclusion.

I like the champion rad by itself, but I do not care for any "zip-tie" fan attachment - lots of different companies selling electric fans provide that as a mounting solution, but it is one I would avoid 100% of the time.

BlackC3vette

Inadequate airflow through a radiator with the vehicle not moving (at idle) is a basic diagnostic statement and can not be negated by how many people with a limited technology base call somebody for technical advice.

SH-60B

[QUOTE=The13Bats;1592737357]my bad

I had no idea that you kill 95% of potential sales due to c3's that do not have a vacuum can on their distributor.

I didn't realize so many people didn't use vacuum cans on a c3 street car and have the can removed from their distributors and sure missed where they OP posted he has removed his,

Many thanks for clueing me in, setting me straight and solving his cooling problems....




Yeah, get 'em Bats, for daring to disagree with you about the vaunted Champion Radiator, (because-he-really-bought-a-DeWitts-and-forever-regrets-it), get 'em!

All hail Bats!

The13Bats

Thanks for the support, but actually dewitts is the "vaunted" radiator on this form, ad nauseam,
Disagreeing with me? I didn't see it that way I saw it more as tossing in their 2 cents, we all do that here
If a person does not believe that a widely accepted symptom of not enough air flow can be overheating at idle yet cool running at speeds I am good with that no reason not to be.
Regret buying dewitts? well "regret" might be pushing it a little I admit I wish I had saved several 100 and bought an import radiator,
However,
My dewitts is paid for and is a work of art that I have no doubts will perform as good as it looks....

would it be okay with you if we get back to helping the OP with his cooling and leak issues?
Perhaps you can shine some light on his problems....

Five Oh

Beside my now jacked up radiator. I put the stock back in and fired it up to let it run. I noticed the bottom hose coming from the water pump is not hard and did not feel like water was flowing through the hose. The motor rather quickly got hot up to 220-230 and I shut it off. On top of my fans not coming on due to what I think is a malfunctioning sensor of which just started happening. But this leads me to believe the water pump is out right? I mean both hoses felt no pressure top and bottom...

The13Bats

I sure do feel badly for all the gremlins you have messing with you,

Are you sure there isn't a large air pocket in the system,
It seems to work better filling and burping these when the front is higher than the rear, at my old house the driveway was steep enough, some put the front on ramps or jack it up but air in the system can in some cases be tricky to get it all out,

On your water pump like augiedoggy was talking about sure it could be corroded away,
You could just buy a new pump or if like me ( I am way cheap ) take the water pump off then the rear cover and check out the impeller for rot,

Since you have been having issues I would just use a toggle switch for the fans for the so called beta testing going on, worry about sensors later.

Five Oh

Hmm I just figured starting it and letting it run for a few minutes would sort of burp the air out of the system if the pump was working properly

The13Bats

Sometimes we get lucky other times not so much so,

The pump likes to move water it doesn't move air so well, some people have the system burp and stabilize no issues others have to work to get it right.

Things changed through out the c3 run but basically The c3 has the radiator filler on the radiator lower than the thermostat housing so the air doesn't want to move to the radiator fill, as I was saying I have seen people on here do things like ramps or jacking up the front to get the radiator higher, I do mine on a high angle driveway,

What I do is top off the system with coolant and have the cap off the radiator with it running as the temp starts to head towards whatever temp the thermostat is you might see a little pulsing of the water or even bubbles in the filler then when the stat opens you should have a rush of water and drop in amount in the radiator you can see the coolant moving then top it off and install the cap, this is a good start but in some cases things can be a real pain and still have a trapped air pocket.

Be sure the puke tank has it's water in it.

BLUE1972

Have you checked the lower radiator hose to see if it's collapsing when the engine starts to pump water. Sometimes the suction of the water pump can collapse a cheep hose. This may not happen at idle, but when the engine reves.

That will definitely cause a cooling issue.

Sometimes the answer is to put a "spring" into the hose, as some factory hoses had.

0Tom@Dewitt

My suggestion was to actually help the OP but if enough members shoot the idea down he most likely won't even consider it a possible source of running hot at idle.

Be honest, how many of you even clicked on the link and read it?

To Poo Poo someone that works through more cooling issues than most people, regardless of the owners knowledge base, is just silly. This is not my hobby. I do this for a living and for the last twenty years.

So I will say "Air flow is important!" The more you have, the higher the heat rejection rate. It is a natural assumption to think that if a car cools at speed but overheats at idle, it must be an air flow problem. The OP's dual fans seems like they would do a good job and combined with an aluminum radiator he shouldn't have any issue at all.

So I ask...Do you have a vacuum advance?

Does it work correctly?

Did you buy a MSD distributor without a vacuum can?

These are the questions I ask customers when they have this condition and most of them find out this works. That's all I got.