Cool/Heat: Overheating Custom Restored Studebaker C Cab Truck - 76 Camaro Front/Rear Chevy 350 Engine

[MIKWIN]

My truck is overheating. It is a custom restoration 1952 Studebaker 2R6-12 with a 76 Camaro front/rear end and Chevy 350 engine.

On a 75F day it averages 180F engine temperature as long as I am going down the road at normal traffic speeds. When I stop and let the engine idle, after driving the truck for 10 miles or so to warm up the engine, the engine temperature will gradually rise as high as 220F within 10 minutes or so depending on ambient temperature. I have not let it go above that...not sure even if it will. The engine compartment gets pretty hot regardless of the ambient temperature.....when I stop and turn off the engine I always open the hood to let the heat escape. My truck engine overheats faster when the ambient temperature is higher. I live in Las Vegas so it is hot here much of the year.

It has a 3-row down-flow Champion aluminum radiator with a core area slightly larger than the Camaro donor vehicle I got the engine from. I have a high-flow long water pump (Flokooler), and oversize pulleys for maximum water pump flow rate. The radiator has a Derale dual 11" electric "puller" fan mounted on the engine side of the radiator, with a 3750 cfm air flow, and a rubber seal at the interface to ensure it pulls air through the radiator. On the front of the radiator is an a/c condenser mounted with a 5/8" gap between it and the front of the radiator. I don't think my radiator, fan, or water pump are part of the problem. I don't know the thermostat "open" temperature, so that is an area for investigation.

I have some ideas...and maybe there are multiple contributors or just one of these. It may be the coolant mix, the thermostat rating, and/or cooling air flow. My plan is to
1) Check the coolant/water mix and change it if necessary to a 40/60 % mix for good heat transfer,
2) Remove the thermostat and find out what I have and possibly change it (to what I am not sure yet),
3) Make sure I don't have hot engine air being sucked around and into the radiator front end.

Right now I my suspicion is that number 3 is the main culprit. So I plan to do some measurements of air flow and temperature inside the engine compartment with the hood closed. I'm still working out how to do that, but that is my plan so far. I bought a $13 "pocket" anemometer that also measures air temperature, which I plan to mount in and around the radiator somehow to take some measurements and a $22 coolant refractometer to check the coolant mix percentage. Depending on what I find out I may have to improve the cooling air flow situation when the vehicle is not moving.

I have several pictures that should help. If anyone with experience with a problem like this has suggestions, please let me know. I could use some help. Thanks in advance for your time if you can point me in the right direction. I have a ton more pics and information if I left something out let me know.

[Studius]

MIKWIN, awesome looking truck. I had your almost exact situation a few years back. Also had much of the same equipment you have: SBC and big aluminum radiator and extra fans and shroud. I also tried much of what you've done. I finally solved it 100% by putting the stock water pump back on. I believe the FlowKooler pushes the water through the radiator too fast. Once I put the stock pump back on I had no more overheating - ever. The FlowKooler went in the swap meet box. How about sharing some more photos of your beautiful pickup?

[MIKWIN]

Thanks very much for the reply Studius, I appreciate it!! I have read that a too-high flow rate could result in overheating, and it makes sense. I don't have extra fans, and I don't have a shroud, but maybe that does not matter if the flow rate is too high then the heat is just not transferring to the coolant as it should. I wish there was an experiment I could do to confirm.........any ideas? What did you do, if anything, that led to putting the stock water pump back on? Do you recall if you ran the Flokooler without a thermostat? Did you suspect the Flokooler had failed, therefore the reason you replaced it? Sorry for all the questions. Changing out my water pump is a major PITA so I am trying to be sure before I dig into that project. Here are some more pics of my truck....glad you like it. I love my truck! Can you share a pic of yours? Thanks again!!

[StudeRich]

In Las Vegas, there would be no reason to run any Higher than a 180 degree Stat, that is the FIRST thing to replace, it's probably a 195 or 205.

Watering the Anti-freeze down won't do much except cause more Rust.

[studegary]

I like your pickup. I owned two C-cabs with GM sub frame and 350/400 engines, A/C, etc. I didn't have a cooling problem with either.
Is your fan thermostatically controlled, if so check that it is coming on properly, switch controlled or on all the time?
I suggest a 180 thermostat and a 50/50 antifreeze mix.
I think that between the pump and the pulleys you are chasing the coolant through the radiator too fast.

[Corbinstein0]

an experiment might be to pinch one of the hoses about half-way and see if that slows down the flow enough to create transfer.
You DO NOT want to pinch if completely off. If it does, then you need to either slow down the pump, or replace it and go back stock.

[swvalcon]

If i where you I would buy a new not rebuilt Chev water pump and put it on. Think about it those stock water pumps have cooled billions of small block chevs from 1955 and lasted for millions of miles. Pretty hard to beat that . Most aftermarket pumps just look nice don't work better.

[sweetolbob]

Remember that the thermostat only controls the temp until it's wide open and after that it's the thermo capacity of the system controlling temp. So if you want to change the thermostat, no problem if you want to see if it's restricting flow, but it probably won't change your overheating issue as long as it's working properly.

I like the pulley change idea as they made so many SBC's that finding a larger pump pulley to slow down the pump shouldn't be difficult.

Lastly, SBC's changed WP direction based on the usage. Be sure your's is the correct rotation for the application.

Bob

[junior]

In agreement with what others have said re: 180 t-stat, stock water pump and pulley size. Other than that is seems like all else is in order...but one thing that has not been answered is ...do you have the correct rotation of waterpump? Looks like you have a serpentine belt drive and that confuses some folks in making them think they need a reverse rotation waterpump, but in your case, since the belt is running over the waterpump pulley a standard rotation waterpump would be required. Just a thought. Beautiful truck, hope you get it to cool properly. Cheers, Junior

[junior]

opps, looks like Bob beat me on the draw about waterpump rotation...damn. Also regarding t-stats, running one typically aids cooling as opposed to not running one, as some folks yank them out of the system thinking cooling will increase, but that only decreases the amount of contact time that the heat has to transfer from the engine to the coolant. Also, if all else fails, consider engine compartment flow...perhaps the cooling system is doing the job but the hot air in the engine compartment is not being exchanged fast enough. Just another few thoughts. cheers, junior

[tsenecal]

Some racers just run a large washer in place of the T-stat. The hole size can be varied to restrict flow, but it is something that won't stick closed in the middle of a race.

[MIKWIN]

Thanks everyone for the great responses.

Regarding my Flowkooler high-flow water pump.....the spec indicates it pumps coolant the same regardless of the direction of rotation CW or CCW.

I also found this interesting article by the manufacturer Flowkooler, who states that contrary to popular belief, slowing down the coolant flow rate does not result in a cooler running engine.
https://flowkoolerwaterpumps.com/pag...nd-overheating

[MIKWIN]

Update...thanks for all the suggestions. I am not ruling out any of your ideas/suggestions, but I am going to do some things first that don't involve taking my truck apart and replacing components (water pump, radiator, etc.). First I will check the coolant mix and the thermostat and make adjustments if necessary to a 60/40 coolant mix (for better heat transfer) and a 180F thermostat. I don't expect that to change anything, but at least those will be checked off my list. Then I'm going to explore the cooling air flow.

Feedback welcome on my first simple experiment.....I will drive my truck until it is warm (180F engine temp going down the road), and then stop with the engine idling. I expect it to start overheating as always, and when it reaches 200F I am going to open the hood and watch engine temperature. If the temperature drops when I open the hood that will point to a possible excess engine heat under the hood, and/or a cooling air flow problem......possibly hot air being pulled into the front side of the radiator.

I am also going to attempt to temporarily mount my pocket anemometer in various locations under the hood, near the radiator, and see what the air flow rate and temperature is at those locations. I'll be back with the results of that, and depending on the results I'll decide what to do next.

Please keep the suggestions and feedback coming if you have any other ideas. I appreciate your ideas. Thanks.

[junior]

Regarding the Flowkooler website...if the pumps are so good, why does the site not provide any empirical evidence of the pump's superior performance? Just wondering. Also wondering why the site indicates that a short SBC water pump is the correct pump for a 1967 Marlin equipped with a 327 engine...first I've ever heard of a Marlin equipped with a Chevy engine...perhaps they didn't do their homework and realize that AMC built 327 engines too? Anyhow, luck with getting your truck to cool...being in Vegas is taxing enough on any cooling system. Cheers, Junior

[junior]

A while back this year I referred to a HOTROD mag article on cooling at low speeds...and a poster asked me to post it and I couldn't find it...well here it is. I found it interesting even though in my neck of the woods cooling an engine is usually not a problem for many builds. cheers, Junior

https://www.hotrod.com/articles/stop...0hp-ls-engine/