[38 old coupe]

Hello everyone
on my coupe the car runs around 190* give or take a few degrees I have a 180 * thermostat in their in 100 degree temps it still runs less then 200 going down freeway and traffic.
next when I run the air conditioner the outside temp was around 85 or so running down the freeway at speed the temp goes up 190 to 210.
and In stop and go traffic the temp went up to 220 plus.
I turned off the air conditioner it took a while for the electric fan to get it cooled back down to 180-190.

ive pulled over last summer when it was 105 outside temp out and car was running 220-230 with ac on and it wasn’t boiling over.
it has a 16 electric fan from the info on The fan its a 1000 cfm

Here is the radiator in the support.
I have read i need flaps so air will flow through when going down the road .
should i add and if so what should i use for the flaps?

next i also have read i need to fill in above and below the radiator so air wont flow though their instead of the radiator?

another question.
I have the stock p59 from a 04 Tahoe programmed for the 6.0 lq4 and the computer turns on the electric fan ..
i was wondering when im driving down the road at 60 mph and the temperature is above when the turn on does the computer still turn on the fan?

i talked to vintage air today he was telling me the fan should not turn on when im going above a certain mph.

Sorry so many questions .
thank you kelly.

im planing on driving the coupe from Seattle wa area to west Yellowstone car show next summer and visit Yellowstone for the first time .

 

[39 master]

Sounds like your fan is big enough to move the necessary amount of air so I'm guessing the radiator doesn't have the capacity to cool things off. When your fan does kick on have you noticed if the temp gauge jumps maybe 10 degrees? Sometimes things share a common ground and it will affect the temp gauge reading.

Not sure about the fan not kicking in at highway speeds but my thoughts are the computer gets an input from the coolant sensor and starts the fan regardless of speed.

You should be able to wire in an override switch so you can turn the fan on whenever you need to. Like a hot day traveling at 60 MPH and you will be pulling off for gas or onto surface roads. Start the fan BEFORE the temp starts to climb.

One last thought. Is there a way for large amounts of air to get out of the engine compartment? At highway speeds if air is getting stacked up under the hood this will affect cooling lots.

With antifreeze and a radiator pressure cap you should not boil at 230.

 

[38 old coupe]

The radiator is a 2 core from superior radiator it came with the fan I haven’t noticed any jumping on the gauge i data logged it when i drove to Portland
second i thought about putting in a light just to see if the fan comes on at speed at higher temps .
i figured the computer would get the info from the sending unit and turn it on at any speed ..
the guy at vintage air said if the fan is running as going freeway speeds it would be fighting the fan ..

on the sides of my hood their are areas to let the air out
in the engine bay their are 2 spots not sure if they are enough

im than king that maybe there isn’t enough to let the air out.
I thought about making flaps in the inner fenders and i was thing on a hot day this year take the hood off and see if it helps .

yea at 230 it wasn’t boiling over i was thing it was getting to hot so I pulled over and it was fine just warm.
here is what they are using 1” tubes
thank you for helping

 

[BogiesAnnex1]

Driving 60mph shouldn't turn on the fan in that it is unlikely to flow more air than the Ram effect at that speed. That’s not to say the engine isn’t hot and the trigger mechanism doesn’t turn the fan on, rather it is to say running the fan at road speed is unlikely to affect a temperature reduction.

What needs to be considered is Delta T between the temp of the incoming air and the temp of the coolant entering the radiator. The closer the incoming air temp is to the coolant temp the hotter will be the coolant temp. Running the air conditioning adds heat seen as temperature to the air flowing into the radiator and adds a power load to the engine. So your reducing the air’s ability to extract heat from the radiator while adding more heat from combustion and friction into the coolant.

Looking at the picture the shroud is not very deep and certainly not very streamline. It’s unlikely that the airflow across the face of the radiator is consistently high but rather mostly concentrated in the area immediately before the fan with the rest of the area working lazily if at all. You should test it without the shroud to see if there is an improvement at higher road speed, though the trade off maybe hotter at idle and low speeds.

Taking the air conditioning away generally overheating at idle through low speed is a lack of air flow across the core, where at road speeds it’s a lack of radiator size. The latter can be the radiator is simply not large enough or that air flow into the core is too hot or that all the core area isn’t being utilized.

Insofar as being large enough don’t forget that overheating of these old cars was a hallmark of them with a small low power engine. Today with no increase of face area for the radiator we expect them to cool engines that are considerably larger and develop more power, so there is a basic conflict going on. Multiple rows of tubes can help but one needs to consider that as with an air conditioning condenser ahead of the engine’s radiator the tubes following the first row are not as effective at heat transfer as the first row.

The problem you’re having is pretty common, there aren’t a lot of solutions. I’ve added plumbing to the frame to increase capacity and use the frame as a heat sink, add specific coolers for engine and transmission oil this takes some load off the engine coolant. The other is use waterless coolant which has a much higher boiling point like 360 degrees F without necessitating 15 to 20 pound pressure caps that only take 50/50 mixes to about 260 while applying explosive forces inside the cooling system. I never found water waters to offer sufficient improvement.

Bogie

 

[38 old coupe]

Driving 60mph shouldn't turn on the fan in that it is unlikely to flow more air than the Ram effect at that speed. That’s not to say the engine isn’t hot and the trigger mechanism doesn’t turn the fan on, rather it is to say running the fan at road speed is unlikely to affect a temperature reduction.

What needs to be considered is Delta T between the temp of the incoming air and the temp of the coolant entering the radiator. The closer the incoming air temp is to the coolant temp the hotter will be the coolant temp. Running the air conditioning adds heat seen as temperature to the air flowing into the radiator and adds a power load to the engine. So your reducing the air’s ability to extract heat from the radiator while adding more heat from combustion and friction into the coolant.

Looking at the picture the shroud is not very deep and certainly not very streamline. It’s unlikely that the airflow across the face of the radiator is consistently high but rather mostly concentrated in the area immediately before the fan with the rest of the area working lazily if at all. You should test it without the shroud to see if there is an improvement at higher road speed, though the trade off maybe hotter at idle and low speeds.

Taking the air conditioning away generally overheating at idle through low speed is a lack of air flow across the core, where at road speeds it’s a lack of radiator size. The latter can be the radiator is simply not large enough or that air flow into the core is too hot or that all the core area isn’t being utilized.

Insofar as being large enough don’t forget that overheating of these old cars was a hallmark of them with a small low power engine. Today with no increase of face area for the radiator we expect them to cool engines that are considerably larger and develop more power, so there is a basic conflict going on. Multiple rows of tubes can help but one needs to consider that as with an air conditioning condenser ahead of the engine’s radiator the tubes following the first row are not as effective at heat transfer as the first row.

The problem you’re having is pretty common, there aren’t a lot of solutions. I’ve added plumbing to the frame to increase capacity and use the frame as a heat sink, add specific coolers for engine and transmission oil this takes some load off the engine coolant. The other is use waterless coolant which has a much higher boiling point like 360 degrees F without necessitating 15 to 20 pound pressure caps that only take 50/50 mixes to about 260 while applying explosive forces inside the cooling system. I never found water waters to offer sufficient improvement.

Bogie

Thank you.
i guess 230 deg at 105 temp out side isn’t so bad then
yea with such a narrow radiator i get it .