440 Water Pump Pulley/Crankshaft Pulley Sizing to Overdrive Water Pump

[MoparCarGuy]

Exactly. And have you actually tested the coolant temp before and after the thermostat ?
Are you relying on your dash gauge for the temperature reading ?
Did you test your radiator cap. They go bad quite often and are seldom even considered.
16 lb cap raises the boiling point considerably.
Modern cars run over 200° all the time on purpose to help lower emissions.

What process would tell me temps before and after the 195°F thermostat? I have a laser thermometer but have not checked the water pump housing temp or any other area with it.

I tested the thermostat prior to installation in a pot on the stove. Started opening at 192°F and fully open at 195°F so it is good.

I am monitoring the temperature with the Digital Coolant Temperature Sensor (CTS) on the EFI display and also the factory gauge. The factory gauge never leaves the upper portion of the marked normal range.

Cap is repro 16psi and is 20+ years old. Radiator cap is not releasing any overflow or boiling and both gaskets look new. I could get the auto store’s loaner cooling system pressure tester to test the system and cap but it is not overheating or boiling over.

Consensus is there is not a problem so I will monitor temps when in traffic. I have the EFI display CTS programmed to change from green to yellow at 210°F and from yellow to red at 215°F.

 

[Challenger RTA]

Just a simple thought. Did you recheck the thermostat? I have had only 1 or 2 newish ones go bad over the decades. It might have been my error. As on some newer cars the radiator has to be burped. So would a high flow pump churn up the water an not let out all the air at once. When you change one thing it changers an other. Cause and effect. Going from one extreme to an other.

 

[moparleo]

I learned a very long time ago to never assume because something was working before, that it still works now.
Ever have a light work and then not anymore ?
These are not aircraft precision parts.
Anytime you are trying to diagnose a problem, you always start at the beginning and with the most basic parts.
I have found after many years in the automotive repair business that 90 % of the time it is the very basic, simple stuff that fails.
Time is not the friend of belts, rubber, liquids, gaskets, seals.
They must be serviced/replaced on a time or miles basis. Which ever comes first.
New does not always mean good. Always verify if a part is good, if you can before you install it.

 

[MoparCarGuy]

I tested the thermostat before installation and I can see the temperature change when it opens. I can also see the coolant flowing into the radiator with the cap off.

My conclusion is 90+°F days with “feels like” temps over 100°F are taxing the system at idle and in traffic with the A/C on Max.

Tomorrow, I am changing the coolant ratio to a 70/30 water/antifreeze mix. I will take some CTS temp photos afterward and laser thermometer temps of the water pump housing, intake, heads, etc.

Temp right now.

 

[moparleo]

Idling is when the cooling system will run its hottest. Proper size/type fan blade and thermostatic fan clutch/shorud are your friend. 200° + is not unusual or worriesome if it does not continue to climb much above 215-220.
Thgis is wehere electric fans shine. At idle speeds. just keep air moving through the radiator and you should be fine.
Remote trans cooler if automatic.
And also note thaty as the radiator gets hotter, it will transfer some heat to the condenser causing a/c temps to also go up until you get moving.

 

[MoparCarGuy]

So here are the results of changing the coolant-to-water ratio to 70/30. Spoiler: Ended up with a 74/26 ratio (74 antifreeze/26 water).
BTW, the existing 24-year old Modine 26" radiator is a three-row with 1/2" tubes. Far from ideal considering what is available now.

I had to put my brain in gear early this morning to figure out how to make the change from 50/50 to 70/30 without draining the block, heads, etc. Looking at the FSM chart (posted earlier in this thread) I noted the capacity for a 26" radiator/440 engine system is 17 quarts (4.25 gallons). To get from 50/50 (2.125 gallons water/2.125 gallons antifreeze) means I had to remove about 2.125 gallons of the 50/50 mix and replace it with 2.125 gallons of distilled water. I figured it this way, half of the mix was antifreeze and half was water. That is antifreeze (1.0625 + 1.0625 gallons) and water (1.0625 + 1.0625 gallons). Removing exactly 2.125 gallons of 50/50 and replacing it with distilled water would mean the mix was 3.1825 gallons of water and 1.0625 gallons of antifreeze. A ratio of 75% water to 25% antifreeze. Not exactly what I planned but close enough.

I removed the radiator cap, opened the radiator petcock, and drained the radiator into a pan. The radiator stopped draining and I closed the petcock. I measured the amount in the pan and it was almost exactly two gallons. Missed the 2.125 gallons by 16 ounces. Oh well, replacing less than 2.125 gallons would yield a bit more than 25% antifreeze which is better but here is the math for the resulting ratio.
4.25 gallons of 50/50 minus 2.0 gallons of 50/50 leaves 2.25 gallons of 50/50 (1.125 water to 1.125 of antifreeze). Adding back 2 gallons of distilled water to the remaining 1.125 gallons of antifreeze yields 1.125 antifreeze divided by 4.25 capacity or 26.47% antifreeze/73.53% water.
Essentially a 74/26 ratio (74 water/26 antifreeze) and close enough without having to drain the block.

Test Drive
I headed over to a buddy's house to check out his `69 Dart with a MP crate motor 392HEMI, dubbed "Dart Vader" (pic below), and the temp did not reach 195°F. I did not run the A/C on the way over. His place is only a mile or so away and the speed limit is 30 mph so ambient temp was around 82°F at 10AM. The 195°F thermostat never opened (reached about 185°F when I arrived at his house) so I hung out at his place until around 12:30PM and then headed back home. The ambient temp was up to 91°F and felt like 101°F so I ran the A/C on High on my way back home.

Coolant Temp reached 195°F as I pulled into my driveway and I figured I would let it run standing still with the A/C still on High. The peak temp on the EFI display was 215°F and stable for well over 5 minutes and this was with both 9" electric fans turned OFF (disabled by dash-mounted switches). I decided to try a theory to increase water pump speed/flow and rev'd up the RPMs to about 1800. The temp fell about 2°F. More water flow seemed to help. I then re-enabled the electric fans and the temp fell to 202°F. That was better than I expected.
I took a temp reading of the water outlet when the thermostat opened and it was 195°F as would be expected.
I also took a reading of the lower radiator hose temp and it was 183°F which seemed to show the radiator was dropping the coolant temp by about 12°F before it entered the water pump inlet.
Everything seemed to be very stable and no signs of going above 215°F with the A/C running without the electric fans AND approximately 202°F with the A/C running with the electric fans. All in all not bad for the Florida heat.

I will monitor the temp closely as the weather gets even hotter in JULY and AUGUST. Our car show season is really from OCTOBER through MAY but there are still a few cruises happening year-round.
Thanks for everyone's input.

 

[Steve340]

That radiator may prove to be the Achilles heel of your cooling system.

 

[Challenger RTA]

Thanks for your informed replay. I was not a fan of electric fans. I thought and felt they would be more of an obstruction. I would now consider this as safe guard from over heating. The quality of the fan is probably the difference. As far as the radiator. AS Steve340 pointed out. That radiator may prove to be the Achilles heel of your cooling system.
There are or maybe better ones then stock. My personal preference and opinion, the brass is more durable and I like the look of the factory radiator it doesn't deter from the factory look.

 

[MoparCarGuy]

Thanks for your informed replay. I was not a fan of electric fans. I thought and felt they would be more of an obstruction. I would now consider this as safe guard from over heating. The quality of the fan is probably the difference. As far as the radiator. AS Steve340 pointed out. That radiator may prove to be the Achilles heel of your cooling system.
There are or maybe better ones then stock. My personal preference and opinion, the brass is more durable and I like the look of the factory radiator it doesn't deter from the factory look.

@Steve340 @Challenger RTA
I will likely plan on getting a Glen-Ray reproduction radiator with their Max Cooling option which is brass with 5/8" tubes & 7/16" spacing.

My preference is also stock-appearing and the durability of brass. I do not have an original 2998956 radiator to send to Glen-Ray for restoration.
That would be far more economical than buying a new reproduction.

This winter is on track to be a TKX 5-Speed/Pistol Grip installation. Hopefully, the Modine radiator will carry me through to the cooler months.

 

[Steve340]

I think your current radiator will be fine. It may last another few years if the cooling system is not really pushed. Just monitor it like you said in earlier post.
That Glenray radiator looks like a good option.