The Stovebolt Site Forums The Shop Area Engine Shop Need Help: Radiator problem

I have a 235 in a 1949 Chevy 6400. I have an electric fan in it. It has been over heating when the motor is under a load. Example; I hauled 3 cord of cedar logs, when I would go up a hill and put a load on it you can watch the temp. gauge go up, go back down hill it goes back down but not as fast. If you pick up the radiator it is alot heavier on the bottom. I have had it cleaned and did not help. Took it to a shop to get recored and they said that it was not flowing real well and it would cost $500 dollars to recore. What should I do?

Please define cleaned. If it was just cleaned with a chemical remover, that may not do the trick.The radiater shop needs to rod out your radiater. $500.00 to recore is way to high. You can check the links pages for the vendors who will sell you a NEW complete radiator for much less than $500.00. I'd find a different radiator shop.

You can look inside radiator for evidence of corrosion and plugged cores. When engine is running (safer if recently turned off), feel around radiator for "cool spots" that indicate no flow of coolant thru a section of cores. What size fan you got? I've got a 16" electric pusher and no mechanical fan on a '60 235 in a '54 bel-air. Keeps it cool with a 160 deg thermostat. Check water pump, thermostat, coolant mix, and for corrosion in water jacket of head or block.

What year 235 you have? The '55-62 2nd series engines had better water pumps/water jackets than the '53-'55 1st engines.

Ignition timing (base and advance curve) have a lot to do with overheating under load. So does octane of fuel used and fuel delivery issues (carb jetting/adjustments, vacuum leaks, etc)

chip

I don't think my fan is 16". What cfm is your fan pushing. I can't go to another radiator shop. There is not any around, I had to go to Columbia for this one.

If you bought an aftermarket fan from an autoparts store it is probably too small. I think about 2500 cfm is the minimum for a worked 235 or 261. Mine is a 16" 2500 cfm and it draws about 15 amps when running. I had to look for it to find it, most of the fans were for auxiliary use and were less than 2000 cfm. My truck never overheats but it never gets very hot here and I haven't hauled any heavy loads in stop and go traffic. I've sat in the dump line for an hour with it running and no problem, though.

In the meantime, you may want to check your antifreeze mixture. 50/50 doesn't transfer heat as well as 30/70, and you can add some water wetter for a bit of added efficiency. Just make sure you check it before winter.

4onthfloor, I think it is only 1900cfm or 1600cfm, I can't remember. Do you think I should still do something with the radiator. I probably need to do both the radiator and the fan. How much did your fan cost and where did you get it.

Sounds like two problems, the radiator needs recored and the fan size being too small.

Since you have a 6400 series, your radiator should be a 4 row, and should be taller than one from a pickup. It will probably require a custom made core, which is why the price is so high. You might try calling a shop in a bigger city, but you will need to have the dimensions of the core in order to get a price. See what you find. I think the local shop is kind of high, but you never know.

Thanks a lot guys. The radiator shop is the only one around the area. I guess I will just bite the bullet and get it recored.

Take some measurements of the core, top to bottom, and side to side, and post them or email me. Also count how many rows of tubes the core has. I've got a catalog from a radiator supplier and I might be able to match up a new radiator which will fit your dimensions. That price on a recore sounds like you'd better bring a big jar of vaseline next time you visit that shop! Can you post some pics?
Jerry

Hotrod Lincoln, I don't have the radiator. It is at the shop a hour away. They orginally had quoted $250, but when they saw that it was a v-core, they said that those are hard to fit, or something like that. I told them to hold off until I did some more investigating.

OK, no hurry. I can probably help out with something that will fit, with some dimensions.
Jerry

In my "Brothers Truck" catalog, it lists a brand new heavy duty radiator for $280. I wouldn't even mess with the 50+ year old radiator, especially if it's a working truck. I would get the new beefed up radiator, flush the engine and heater and put a 50/50 antifreeze/water mix in it and be done and reliable for years. There are other vendors to choose from, "Brothers" is just what I had handy.
Scott

Make sure you have a thermostat and that it is a good one.

Believe it or not but the absence of a thermostat will cause overheating because the coolant flow is too fast and does not remove the heat from the engine as well.

Had the same problem with overheating only during the hot summer months when going uphill or longer freeway rides.
The quickest way to cool it down again was going downhill in neutral.
I went through two old radiators. The last one was better and looked very new on the outside.
However most all of the old honey comb single cores are partially or over 50% clogged and corroded inside.
Even concrete cleaner over night couldn't penetrate although it appeared that it really did its job.
I went to 3 radiator shops to hear their advice and believe to have found the best solution.
The cost to have my radiator recored or buying a newly build one was both $280.
It's always better to keep your original overflow tank, frame and possibly bottom, if it is in good condition or just needs sandblasting.
I got a 3 row modern core from Craig, which is the only way to go.

This summer I can stand in traffic even right after a long freeway ride with no overheating problems.
I also got an additional overflow tank just to be sure.

Bottom line, if you live in the southern states and still have an original honey comb core, have it recored and restored in any case - it is clogged even if you think it isn't.
The temperature sensor doesn't show how hot the cylinder walls really are and I was told that the old sixes were notorious for cracked heads from overheating.

While we are at it....
I am not affiliated with this company, but if you like your engine, please never use a single drop of water ever again.
This alternative really works and is not just another scheme: NPG+
No more worries about corrosion and water hardness and keeps your cooling system efficient for the life of the engine.

I am usually skeptical with all these new snakeoil additives, but this stuff is what every engine would put on its wishlist, no doubt.
All the bliss has it's cost. Not cheap but it's a one time fluid replacement and you never have to worry about your cooling system again.
Even the hoses require less frequent attention.

48Bigtrucks, does the new radiator you got fit in the stock bolt holes? If so where can I find this company.

For what it's worth, my '51 radiator started leaking back in February. Two local shops wanted $400 to recore. I ordered one from Obsolete Chevy in Georgia for $189 brand new. But the new one, with tubes, runs about 20 degrees hotter than the 53 year old honeycomb did. So, still looking for a shop that can fix the leak at the top tank. I think the honeycombs are a lot more efficient but more expensive to manufacture so now we all have tubes.

Coondog - Go to the links section (at the top of this page) and you will find several vendors under parts. In addition to Brothers, there are also some good ones in KC, which might save you some on shipping.

If my radiator is taller than the normal truck since I have a 2 1/2 ton, will the heavy duty that these companies have bolt in? Will it still look stock? I would like to kept this truck as stock as possible.

Coondog,
I also have the taller radiator in my 1/2 tonner.
The replacement cores can be ordered in many sizes, which ever fits.

Another thing that could be done is dropping the radiator as low as possible inside the support by drilling new holes in the mounting brackets of the radiator.
That's when the taller core comes handy, as it still looks stock after it's dropped.

Sorry about not replying right away, I just got back from the Car Craft Summer Nationals in St. Paul, MN. As far as the radiator fit, I've never fit one but I assume it would keep your engine cool since it's a heavy duty radiator for the same size engine you run. I run a 350 behind my original radiator with know problems. So I think a good clean radiator that may need minor refitting would fix your overheating problem. The catalog I've got is also online at www.brotherstrucks.com. The www.truckandcarshop.com also has them. So does LMC and Chevy Duty and many others.
Good luck,
Scott