Cooling system overhaul

[fabio]

Hello guys,
So I just got this 75'Vette and I'm doing some work on the cooling system, I'm planing to put a Edelbrock aluminum pump, a 180degree thermostat, get rid of the cluch and install a 18.25" flex fan. Anyone have tips for me?

I'm kinda confused by the cooling system, this is my first chevy and it seems to be really messed up.

Besides the radiator hose there are two other exits on the water neck, one is closed with a plug and the other has a small tube with two connections, both closed with rubber caps. What are these suposed to be?

On the other side of the intake there are another exit that I thougt would go to the heater but the hose turns around on the ac compressor and connects back to the water pump. What is that? is it pumping hot water back to the engine?or cool water directly into the intake?

Some one knows where I can find a diagram or something that actually shows all the hoses and fluxes in the cooling system? I have a Haynes maintenance manual but there is not much there...


Thanks a lot guys,
Fábio.

[SIXFOOTER]

COngrats on the car, now you need some real books. You need an AIM (Assembly Instruction Manual) and a shop manual specifically for a 75, check Ebay.

The hose from the intake around the compressor to the water pump is heater hose, should go from the intake to the heater nipple on the firewall and then annother one from the other nipple to the pump, possibly thru a shutoff valve. It soumds like it got bypassed by a previous owner maybe because the heater core leaked.
Screw the flex fan, when it turns loose it will go thru the hood. Either put it all back stock, or change over to an electrical fn setup.
Don't waste your $$ on that edlebrock pump either, a new (rebuilt ) pump is only $35 or so, and if is not leaking it is probably fine.
Get a good cooling system flush like they sell at GM, its a powder that you run in the cooling system for 30 minutes or so and cleans out all the crud from the cooling system.

[bmotojoe]

Not sure what water pump is installed in your car with the extra lines that are plugged. The plug on top is normal and is correct. The heater hose making a loop is done to bypass heater core so expect that the core will leak when you repair the cooling back to original is you choose to do so.
In a different post you had,
On the refrigerant discharge to atmosphere by removing hoses when a system is still charged is against the LAW and if caught there are big fines and possible imprisonment. I would have a professional evacuate the system and then you can rip and tear.
Brian

[fabio]

Hey guys thanks a lot for the answers!
In fact the heater hoses are shamefully cut and bended under the fender, that is nasty bypass. On the inside of the car there is some water stains, I suppose you are right, the heater core was leaking...

About the flex fan, what do you mean by "when it turn loose"? When it bends at high rpm or the bolts getting loose and it flying away? The fan clutch seem to be in bad shape and all this stuff is just too heavy. I had a bad experience with electric fans on a Ford Maverick I did in Brazil, the flex fan worked like a charm on that project. But I wil consider it... The expensive pump is to be safe too, dont want it failing on me again(this one leaks a lot), the weight and higher volume can be a good reason too right?

I will try to get the radiator out and do that magic flushing.

I opened the water neck to chech the mistery tube and it seems to be a pressure valve only, not sure why it is intended to but is not being used. there is a similar one on the intake with lines from the carb attached to it... Still a mistery.

About the AC I read about this law in another thread, makes sense.
Thanks a lot for the info.

Fábio.

[fabio]

Ok guys new battle, THE DAMN SROUD!!!
I cant get this thing out, it is completely loose but I see no way to get it out without removing the controlarm or the radiator mounting frame...
I'm about to break it into pieces, please advise!
Maybe a bit of WD40 and some muscle would do it?

[BarryK]

why not stick with the stock water pump? The stock units work great.
The 180º t-stat is perfect
forget the flex-fan! flex fans tend to break and distinagrate and take large chunks of fiberglass with them when they go. I'd stick with the stock fanblade and fanclutch.

On the shroud, it will not come out until after you remove the radiator.
best way to remove is this:

1. undo the upper and lower rad hoses and trans cooler lines (trans cooler lines on auto trans cars only)

2.unbolt the shroud from the radiator top brackets and lean it against the fanblade

3. unbolt and remove the radiator brackets from the core support

4. if you have A/C, unbolt the front AC condenser from the radiator

5. unbolt and remove the upper two core support bolts on each side. There are three on each side but you can leave in the lower bolts.

6. once the top two core support bolts are removed on each side you can tilt the core support forward. It will only go an inch or two before hitting the headlight vacuum actuators but that little bit makes a lot of difference in removing the radiator.

7. now you can pull the radiator out of the core support. It usually requires a little finagling to get the lower hose housing past everything but it will come out.

8. if you need to remove the shroud you can now do so AFTER the radiator has been removed and you do not have to cut it up

On reinstall simply reverse the steps and don't forget new radiator seals

[Vettehead Mikey]

Originally Posted by fabio

Hello guys,
So I just got this 75'Vette and I'm doing some work on the cooling system, I'm planing to put a Edelbrock aluminum pump, a 180degree thermostat, get rid of the cluch and install a 18.25" flex fan. Anyone have tips for me?

Why change all that? You'll spend a lot of money and improve nothing in functionality.

More often that not, the shade tree re-engineering makes things worse not better. Like Barry said, the stock stuff works great.

[chevy6673]

Originally Posted by Vettehead Mikey

Why change all that? You'll spend a lot of money and improve nothing in functionality.

More often that not, the shade tree re-engineering makes things worse not better. Like Barry said, the stock stuff works great.

shade tree re-engineering thats a classic,,and if its not broke dont fix it words to live by good luck

[petes74ttop]

Hi again, The two exits on the water pump neck? If you mean on the thermostat housing, they were for the TCS system, if it's pluged they are bypassed and you can leave it that way with no problems. ( Haynes Page 6-6 ). Pete.

[fabio]

In another thread you were taling about changes to the cooling system that didn't entirely make sense to do as you laid them out.
Maybe it would help to explain what your plans/goals are on this car so we can better understand what you are trying to accomplish and help you out more.

Ok let me open my heart so you would underdstand why I am doing all that. I

I'm a software engineer, and all I do all day is almost invisible. So my hobby is to play craftsman, that way I can see some material result for my sweat.

I'm most extreme DYIer you could ever met, and many times I regret that. Have you ever seen that 60's cartoon about a DIY bear that never wanted to hire a professional? That's me!

So, yes I will disassemble and reassemble it a lot of times just for fun, yes I will re-engineer and get things worse before they can get better, yes I will fix things that are working perfectly. Should I look for a shrink?

Getting to the point, I love american cars, I love the sound of a V8, I mostly came from Europe to the US thinking about re-engineering a rust bucket C3 Vette and a garage filled with tools.

Thats it about me

[fabio]

So this is not the first time I make a project car. Before living in Paris where there is no space or cool project cars, I lived in my home town in Brazil, down there I got my hands on a 1979 Ford Maverick in really bad shape and got it 'done' during two long painfull years.

One of the pain points were the cooling system, I got the car a nice torker II intake a 650cfm Holley, nice flowing headers and yes tweaked the compression rate to 9.6:1, insane high for Brazil's gasoline(82 octanes and below)

Colling became an issue and the winning formula was a high volume aluminum water pump, flex fan, and a taller wider triple(or was it quad?) core radiator.

My plans for this Vette are not much different, better cooling, better flow, better sparks, better... I'm not going all the way to a supercharged frame twister monster, just want a nice looking car with some muscle.

One mistake I'm not making in this one though is the aggressive cam with solid lifters, that was a step over the line, I'm planning to redline at 6k rpm, hidraulic lifters and single springs. Low end torque is the way for me.

Being a sw/hw engineer there are a few strechs that I would make, like spreading microcontrolers among the car and have the lights working thru a one wire network instead of fighting with a 50-wire harness, put some more sensors in the car and monitor more stuff, put some servos in the carb and have a computer controlled carb with my implementation of fire by wire? Computer controled pneumatic valve system? GPS? Vista? Internet connection?

No I'm not going to put wings or knight rider ligths on the front, won't have purple lights underneath, or 18" chrome wheels. I'm not that guy! It will always look 70's, will always sound 70's, but it wont be stock just because, I'm not that guy either.

Take a look on my Maverick pictures you will understand what I'm talking about.
http://picasaweb.google.com/MaverickAzul/Maverick/


Oh and let me say this, I made that project pratically alone and I know how hard it was. Having you guys here arguing with me, questioning, sharing, is PURE GOLD. Thanks to you this project will be much better in all senses!!!!

Thanks a lot.
Fábio.

Ps: Barry, the sroud is out, thaks so much!

[BarryK]

ok, glad you got the shroud out.

next, now that we understand your "motivation" on makinng changes please try to keep this in mind on the cooling system on your car......... many, many, many people have treid to re-engineer the cooling systems on these Vettes to help them run cooler as they can and many times do tend to ran warm or even hot but if you search thru the forum archives you will see that the end results usually fall to two basic answers for a vette to run at the proper operating temps.

1. a completely stock and correct cooling system meaning a correct, properly functioninng original or the even better option of a replacement aluminum radiator from DeWitts along with the correct stock water pump, 180º t-stat, the stock fanblade and clutch, shroud, all the radiator seals, and the correct airdam under the nose.

OR

2. remove the fanblade and fanclutch, shroud and radiator. Replace with a DeWitts replacement radiator and dual spal fans.

most other alternative methods on the cooling system and attempts of re-engineering of the system seems to create thread after thread of continued problems of higher than normal operating temps. These two methods are "proven" to work time after time and you can put your desire to "re-engineer", fabricate, modify, etc on other areas of the car you want to .
Regardless of what you do I'd still avoid using a flex fan because of the horror stories I've heard about them coming apart and causing other damage when they do. i've never heard of a stock fanblade coming apart

[SIXFOOTER]

I agree with Barry's recipe. My version is aluminum radiator with dual 12" electric fans on a DCControl PWM controller. The hi volume waterpump is a waste of time on a street motor if the other cooling components are working correctly.

[fabio]

Ok guys you talked me out of the flex fan thing. But the DeWitts stuff is too expensive for me.
So I'm considering a bunch of options and maybe you can say what you think...
Should I go to a cheaper 16" 2000cfm(noisy?) or dual 12" 1000cfm?

Shroud is really necessary? What is the gain? I see that with sroud the fans will act in the whole surface but without will give greater flow when the fan is not turning an the car is running. 16" is almost the whole surface anyway right?

What about the temp sensor to control the fan? I dont want to loose my heater hose to it, is there something I can fit on that thermostat housing plug?

PWM seems like a good idea if its not $50 expensivier than a relay...

I'm so sorry to not to follow your wise advise and play safe guys. Please don't give up on me, lets make history here

Thanks a lot.
Fábio.

[Vettehead Mikey]

What problem are you trying to fix?