[Formulajones]

I think you'll find that once you move your fan controller from the radiator to the engine like I mentioned in one of the first few posts, you'll see much better control of the fans and engine temps.

Get that under control and get the fans working like they should, then you'll be able to determine if there really is a heat issue and at that point start chasing other scenarios.

Those fans should not be waiting until 220 to kick on when you have a 180 controller.

[andrewT]

yesterday went for a little 30 minute romp. Wired the fans to keep them on the entire drive. Water temps never got over 210, and oil only hit about 230 towards the end of the drive

will check the water pump and hopefully that will help out even more with temperatures

[AG]

Just put a 530 Hp 464 ci in my brother's 1970 LeMans to replace the 350 2 bbl. It has the stock radiator, 10.5 CR with Ali heads, clearance WP, 160 °F Tstat and a 7 blade flex fan and won't go over 165°F on a 80°F day.

[ta man]

I think the next step is to confirm your temp gauge is accurate. Take it one step at a time. It is puzzling on these forums that there are more cooling issues with electric fans and new rads vs good factory pieces.

[andrewT]

Originally Posted by ta man

I think the next step is to confirm your temp gauge is accurate. Take it one step at a time. It is puzzling on these forums that there are more cooling issues with electric fans and new rads vs good factory pieces.

You're right

But I had a factory rad and fan in it last year and it was even worse!
Just didn't get to drive the car long enough before tear down to diagnose the problem. But ya if the factory stuff works, then if it ain't broke don't fix it!

[Formulajones]

Originally Posted by ta man

It is puzzling on these forums that there are more cooling issues with electric fans and new rads vs good factory pieces.

Isn't it though? Dad's been going through the same thing with his for a couple months now. His 571 ran cooler and more consistent temperatures with the stock shroud and clutch fan using a 25 year old 4 core copper radiator than it does now with a fancy thick 2 core aluminum with 1 1/4" cores and dual electric fans.

We've made a bunch of changes to at least get the engine temps more consistent and slightly cooler, but I think the fans still run a little too much for my liking, especially after a good drive and heat soaking. It does clean up the engine bay and free up some HP, I'll give it that. But I expected better cooling and consistency.

[TedRamAirII]

I think the electric fans/shrouds used actually restrict air flow, through the core. Above 45 mph, a fan isnt really needed.

[Formulajones]

Originally Posted by TedRamAirII

I think the electric fans/shrouds used actually restrict air flow, through the core. Above 45 mph, a fan isnt really needed.

That's what I believe too and exactly what we've been seeing with this setup. We've opened the shroud in spots with small rubber flaps to help airflow and that has seemed to help a bit. I think it could be better but he wants to drive it more for a while and see how things go.

[Scott Stoneburg]

Ive been fighting cooling issues since I filled the block to the bottom of the freeze plug holes. I know everone says there is no heat there so it wont make a difference in cooling. But it takes 1/2 gallon of water out of the cooling system. I am using a Mezere electric. Pump and electric fan. Great for cooling it down at the track. But I am seriously looking to go back to a mechanical pump, will leave ghe electric fan for now. But if I continue to have issues I will go to a plastic fan. I dont want a heavy clutch fan hanging on the water pump at 6800 when I race.

[torqhead]

Originally Posted by adynes

I've noticed that my factory gage isn't very accurate compared to the reading from my efi computer.

Also, in your third picture, is that your sensor mounted in the top of the passenger side ("cold side") tank of the radiator? If so, I think you need to mount it on the other side, the hot side of the radiator (or on the engine itself). Aside from being the wrong side of the radiator temperature-wise, the sensor located there might not even be submerged in coolant, as the coolant level gets pulled down significantly on the suction side. My coolant sensor for the efi (that controls the electric fans) is in the crossover.

AndrewT, I saw your response to adynes and I think there was a misunderstanding. See pic I attached, is this the temp sensor for your electric fans? If so, that's more than likely your issue as it needs to be on the other side of the radiator.

[andrewT]

Originally Posted by torqhead

AndrewT, I saw your response to adynes and I think there was a misunderstanding. See pic I attached, is this the temp sensor for your electric fans? If so, that's more than likely your issue as it needs to be on the other side of the radiator.

yes it is...

thanks

[torqhead]

Originally Posted by andrewT

yes it is...

thanks

I wouldn't waste time doing anything else, change the sensor to the drivers side and make sure it's close to 1/4 or more down from the top of the radiator. If you use the pin type sensor that slides between the fins, just ensure you don't have the front tip of the sensor sticking out past the fins on the front/forward side of the radiator.

Although putting a sensor on the motor isn't a bad idea, the solution of putting the sensor in the radiator close to the input hose from the motor will make the fans turn on when the thermostat opens. It's a solid solution and works just as consistently as using a sensor in the motor.

I've got the flex-a-lite dual fan set up and ran it for 25 years on my GTO, port work, etc., (creates plenty of heat) and just recently replaced the fans with the same thing as one of the motors had failed. I've done this type of setup on many cars and it's worked flawlessly on both the stock radiators as well as the aluminum ones.

[geeteeohguy]

I'll be the first one here to say that there isn't an overheating problem if the coolant is at 200 degrees. The engine is not boiling over per the OP, is not showing any symptoms of overheating, but 200 degrees is seen as an overheat condition. It isn't. 235-240 is. Not 200. The oil temp seems a bit high, though...........
For the past 40 years, I've driven several Pontiacs running 200-215 degrees for 100's of thousands of miles without issue. Sometimes they ran 180-190, on hot days over a lot of ground, hotter. No overheating, though.

[torqhead]

Originally Posted by geeteeohguy

I'll be the first one here to say that there isn't an overheating problem if the coolant is at 200 degrees. The engine is not boiling over per the OP, is not showing any symptoms of overheating, but 200 degrees is seen as an overheat condition. It isn't. 235-240 is. Not 200. The oil temp seems a bit high, though...........
For the past 40 years, I've driven several Pontiacs running 200-215 degrees for 100's of thousands of miles without issue. Sometimes they ran 180-190, on hot days over a lot of ground, hotter. No overheating, though.

Agreed, although the good news is we definitely found an issue as the temp gauge to turn the fans on is installed on the cold side of the radiator. Also, the odds are where it is installed it's potentially not in below the full level that you normally see theses radiators run after they puke at little out post complete fill...

[andrewT]

Originally Posted by torqhead

I wouldn't waste time doing anything else, change the sensor to the drivers side and make sure it's close to 1/4 or more down from the top of the radiator. If you use the pin type sensor that slides between the fins, just ensure you don't have the front tip of the sensor sticking out past the fins on the front/forward side of the radiator.

Although putting a sensor on the motor isn't a bad idea, the solution of putting the sensor in the radiator close to the input hose from the motor will make the fans turn on when the thermostat opens. It's a solid solution and works just as consistently as using a sensor in the motor.

I've got the flex-a-lite dual fan set up and ran it for 25 years on my GTO, port work, etc., (creates plenty of heat) and just recently replaced the fans with the same thing as one of the motors had failed. I've done this type of setup on many cars and it's worked flawlessly on both the stock radiators as well as the aluminum ones.

I installed it on that side becuase there is no port on the driver's side to put a sensor. This is on a champion 3 core...you would think they would put that port on the side of the input hose.
Should I drill into the rad or just mount on the motor?

[torqhead]

Originally Posted by andrewT

I installed it on that side becuase there is no port on the driver's side to put a sensor. This is on a champion 3 core...you would think they would put that port on the side of the input hose.
Should I drill into the rad or just mount on the motor?

I don't know what fan assembly you've gone with, but most of them come with a small probe (see pic) that you can just simply push between a couple of the rows in the radiator between the fins. I wouldn't drill on the radiator.

[Joe's Garage]

It doesn't really matter what the temp of the water in the radiator is.

You need the sensor to regulate the temp of the water in the ENGINE.

Thirty years ago, I tried electric fans on one of my 1970 GTOs. The controller with that setup came with a little rubber shim that went around the probe capillary tube and allowed you to snake the probe into the hot side of the radiator and down into the fluid thru the radiator hose opening. Primitive, but it worked.

The new electrical senders are fairly simple, but they need to sense the water temp in the engine itself, in the top radiator hose or in the hot side of the radiator.

Good luck!

[torqhead]

Originally Posted by Joe's Garage

It doesn't really matter what the temp of the water in the radiator is.

You need the sensor to regulate the temp of the water in the ENGINE.

Thirty years ago, I tried electric fans on one of my 1970 GTOs. The controller with that setup came with a little rubber shim that went around the probe capillary tube and allowed you to snake the probe into the hot side of the radiator and down into the fluid thru the radiator hose opening. Primitive, but it worked.

The new electrical senders are fairly simple, but they need to sense the water temp in the engine itself, in the top radiator hose or in the hot side of the radiator.

Good luck!

Not to be argumentative, just trying to help.

While I agree a temp sensor in the engine is used to indicate engine temp, it's used to provide information on a gauge or fuel injection system, etc.. Sensors don't regulate the temp of the water in the engine, the thermostat regulates the temp of the water in the engine.

The sensor for electric fans is to tell the fans when to turn on, such as 160 or 180. You can connect it to a sensor attached to the engine, but the goal is turn the fans on when the water in the radiator gets to a certain point. If you install one for the fans at the engine the fans would probably run more than required and you've got an extra set of wires going from radiator to the engine, not that it's an issue but it's not necessary.

If you're cruising down the road at a moderate speed and assume there's more than enough air going through the radiator to keep the water cool enough to meet engine demands, the fans shouldn't turn on, but when the engine hits whatever temp you set it for they're now running and not needed.

To put the sensor on the hot side of the radiator, when the thermostat opens to let the 190 degree water or whatever degree it opens at flow into the radiator the fans turn on and it cools as it travels to the other side of the radiator. Right now the way it's installed and if the sensor is actually in water with the current setup, the sensor is reading the water after it's been cooled some by the radiator.

[Joe's Garage]

Not the temperature in the radiator - whether hot side or cool side. If my engine stays close to my thermostat's rated opening temperature then it really doesn't matter to me what the actual temperature of the water in the radiator is.

The only thing that matters about the radiator is that it is efficient enough to remove sufficient heat from the coolant/water to keep the engine below the temp at which driveability is affected or where damage might occur. This ability is augmented by the fan's forced airflow past and thru the radiator's cooling fins and tubes.

The whole idea of a cooling system being equipped with temperature regulators such as thermostats and fans and directed airflow is to keep the engine from getting too hot or too cool so that it will operate most efficiently and at a safe temperature for its' construction.

If the sender/probe/controller is adjusted right, then it will turn the fans on at a certain temperature and then turn them back off at a certain temperature.

You can't set an adjustable fan control to 180 degrees if the thermostat is 180 degrees or the fan(s) will run constantly and those fans and your thermostat would fight each other keeping the engine at your intended temp.

You normally would set the control at 190 or 195, so that if and when the temp rises to that point, the fans will come on and push it back down towards your target temperature of 180 degrees. In an ideal world, you could infinitely control airflow and water flow thru the radiator to keep the engine temp 'just right', to quote little red riding hood.

Driving down the highway, so long as there is sufficient airflow, cooling capacity AND water flow to keep the water in the engine at whichever temperature that you are comfortable with, and that temperature is below the temp at which the fans turn on, they will normally be off. At that point your intake-manifold-mounted coolant thermostat should pretty much control the engine's temperature.

If or when the cooling system is temporarily overloaded while driving down the highway at speed, say with A/C running, going up a long grade or even extreme outside temperatures, the temp will rise until the fans kick on and force additional air thru the radiator, increasing it's cooling ability. Once the temp drops back down, the fans go back off. Same way the thermostatic fan clutches work.

At lower speeds or sitting still, the fans will come on more often, but still cycle as the water gets either a little too hot or a little too cool. Sometimes the fan(s) will run almost continually if the outside air temp is hot enough.

The water in the upper hose and hot side of the radiator will be pretty close to the same temp as whatever temp the thermostat is maintaining, so the precise mounting location for an electric fan probe or sender is not critical so long as it is on the hot side of the cooling system. I've never had a radiator with a fitting on the hot side, thus my suggestion to mount the sender/probe in the water crossover.

Regardless of where it is mounted, if it IS adjustable, you can always 'fine-tune' the adjustment to get the fans to kick on precisely where you want them to. If it is NOT adjustable, you would need to tune the system to keep things at your targeted temps by changing the sender to one that closes at a higher or lower temp.

The temp on the cool side of the radiator will be around 20-30 degrees cooler than the hot side, depending on the efficiency of the radiator in removing heat. Mounting the sender on the cooler side, as the OP has, would allow 20 or 30 degrees of additional heat to build up in the engine itself before the water on the cooler side of the radiator got hot enough to trigger the fan relay(s).

In that case, a sender that was adjusted to trigger the fans at 190 would actually allow the engine to get up to around 215-220 before the fans kicked on.

Having that sender in the crossover as I suggested, or at least on the hot side of the radiator, shouldn't let that extra 20 or 30 degrees happen.

As noted by several members, running at or about 200 degrees probably won't hurt anything. The original engines in our cars ran at close to 200 degrees almost continually and they ran for 100,000 miles.

And, as Cliff and others have pointed out, CHECK YOUR PUMP CLEARANCE and make sure you have the CAST IMPELLER. Both of those items will make a HUGE difference in how efficiently the water pump works.

Good luck!

[andrewT]

Originally Posted by torqhead

I don't know what fan assembly you've gone with, but most of them come with a small probe (see pic) that you can just simply push between a couple of the rows in the radiator between the fins. I wouldn't drill on the radiator.

Ya I know those probes. This champion rad came with nothing but a rad. And ya I'm not about to put a bunch of metal shavings into the rad.
Looks like water crossover will be getting a sensor and I'm going to pull apart my water pump