VCCA Home Forums TECHNICAL - 1945 AND NEWER 1949-1954 Cooling system

Hello, I am new to this wonderful sight and I need some advise on my 53 Chevy 1/2 ton truck. It has a 61 235 motor. This truck sat for ten years and the old owner would start it up about every two weeks. I bought this truck about a year ago and have restored it the best I can. The problem I am having is that when I drive it on the road it run about 180 degrees. When I stop at a stop light and the light is a long one it will go up to about 190 to 200 degrees. I had the radiator boiled out last week and it still runs the same way. Let me note that the weather here in Calif. has been about 95 to 100 degrees. Is this normal? I am running a 180 thermstat. Any advise would make my day. Thanks...Oscar

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Now that the radiator has been worked on, I would do some serious flushing of the engine. A combination of water and air is the recommended solution. The thermostat could be reduced to 160 degrees if you can locate one. (Leave the thermostat out until you have finished flushing the engine.)

Thanks Ray, last night I opened the petcock on the block and nothing came out. I have already found a 160 theromat and plan to flush the motor this weekend. The truck manual mentions a reverse
flush but dosen't say how to do it. Do you know a good flush product that I can use? I think my jets inside my block are clogged.Thanks...Oscar

Hi Oscar,

The normal path of the water is up the upper hose and into the top of the tank. To reverse flush you would remove both radiator hoses and have the flow from the upper hose, through the engine, and exit the lower hose. Disconnect both hoses to the heater, we don't want any of the 'crud, to get into the heater core. Flush the heater by it' self. Go both ways and have the heater set on max-heat on the dash. Make sure you remove the drain plug on the back side of the block.

For more advice on flushing radiators/blocks do a search on this forum and you will find many. I run a mixture of PRESTONE SUPER ANTI-RUST and good water year around. (All cars spend the winter in a heated show building so freezing is not a problem.)

If you want to get serious, remove all the "freeze" plugs you can get to easily. Run a stiff but flexible wire into the freeze plug holes and the drain plug hole.

Thanks Ray, I will do this this weekend. The heater is not hooked up yet but will be soon. Is the drain plug on the back of the block the pet cock and can I remove it and just put in a plug?Thanks for the advise...Oscar

Yes, the pet-cock is the rear drain location. It can be replaced with a plug, however it would be more user friendly if you used the pet-cock.

I printed my membership form and will be sending
it in tommorrow. All you guys are greate and I am
looking forward to becomming a member. Does this mean I will be a local? Thanks for all the advise and help...Oscar the grouch

Be sure to follow the advice on doing the heater core it can be done with the block but seperate is better, however be sure to do it now and do not hook it up with out flushing or you will just flush a bunch of rust back into the radiator and the block.

Thanks Glyn, the heater that is in the truck is brand new. The person I bought the truck from said it needed a heater core. He didnt know what he was talking about because the heater core is built in the heater. It has two tubes sticking out from the firewall. Should I still flush the heater core? Thanks again guys for all the help...Oscar

I would at least do a cold water flush of the heater just to check on the color of the water that comes out.

Maybe the P.O. meant the heater core leaks, thus the reason for needing a new core? If you are running a 50/50 mix of antifreeze and water, the boiling point is somewhat above that of plain water, so a heat gauge going to 200 won't loose fluid except that lost due to expansion of the fluid due to heat expansion, keep the coolant within a finger's length (3" to 4") down in the radiator neck. You should be ok when you install the proper 160 thermostat,
what fan are you running ? they make a heavy duty truck fan with more blades on it than a standard fan.
When the later model engine is installed in a 49-54 truck the fan is lower on the stock radiator and does not give as effecient cooling air flow and the older engine and it's fan.
I would be sure the petcock is opening, pull it out and check it.

Thanks MrMack, I flushed the radiator last night and run a cleaner through it for about 1/2 an hour. I couldn't get the petcock on the block to open because the the little wings are stripped. I will have a shop replace it. I did put in a 160 theromat. After all that I took her out for a test drive and everything seemed fine. She ran 180 185 degrees. That was in the evening though. I wasn't very hot outside. My fan is hevyduty, it has six blades and you are right about the radiator is not centerd with the fan. I will be driving here this weekend and will keep an eye on the temp gauge. The tempgauge is not stock but will be soon. Thanks...Oscar

In the evening when it is cooler, a temperature reading of 180-185 degrees is still a little too hot.

:( :(

Yeah , A little too hot where? In Alaska after dark it would probably be too hot also, but the heater would be nice and toasty,and the engine would probably benefit from the extra heat. The temperature gauge reading is the temperature of the coolant, and not entirely an indication of the engines operating temperatures, oil temp, cylinder temp, intake temp, exhaust temp. and what is correct coolant temp for one engine could be not correct for another engine of the same type and model.

In anyplace where the median air temp is 90-100 degrees F cooling the coolant down to 180-190 Degrees in a stop and go situation shows that your engine cooling system is doing a creditable job.

"In anyplace where the median air temp is 90-100 degrees F cooling the coolant down to 180-190 Degrees in a stop and go situation shows that your engine cooling system is doing a creditable job."

If "Rust To Shine" was driving his car under those conditions then, yes, his coolant temperature would be fine. However, the above is just a guess since Oscar didn't give the median temperature in his posting, nor did he mention the driving conditions. He did say that it was "cool" outside, so next we have to determine what "cool" is. However, on an evening when the temperature is only 60 to 70 degrees then 180-185 degree coolant temperature is still a little too hot. But again, in Texas when it is 100 degrees at midnight then 180-185 degree coolant temperature would be just fine!

:p

Hi Guys, on the day my truck was getting hot it was 100 degrees. I have many long stop lights I have to stop at. The reading on the temp gauge would go up to 200 degrees when I was at the stop light. When I would drive thriugh the green light the temp gauge would start to drop. Then another light and another and another. When I got home the reading was about 197 degrees. Is this normal for this kind of heat? Last evening the outside temp was abuot 80 th 85 degrees. My temp gauge only got up to about 180 to 185. Some one told me to get a cooling fan but to me that would not fix the problem. These trucks ran all these years without one so why should I need one.
Thanks...Oscar

Hi Oscar,

Hope I have not skipped a function in this string.

Have you flushed the heater core yet? Did it in fact have a hole in it?

I would now concentrate on the heater. If it checks out as serviceable, I would connect it up to the engine. In the off-season, a heater serves as an additional surface to extract some heat from the coolant. May just be the additional cooling needed to solve your problem.

I have all the hoses but I have to figure out how to hook them up. There are two outlets on the waterpump and two outlets on the firewall.
then I have two outlets comming from the heater core. I might add that this heater is brand new and has not been hooked up yet. Do I still need to flush it. My truck is going into the electric shop next week to have all the old gauges removed and the new rebuilt speedo and gauges installed. The heater power will be hooked up along with the stock AM radio I bought. I am going to the place all of us car nuts go on Wednesday. There is a girl there with a 53 Stock truck 235. I will take notes on where the hoses connect to. Thanks...Oscar

Okay, let's use my '51 Chevy 2 ton truck as a comparison. On a 100 degree day, stop and go driving, the temperature gauge will read around 180 degrees. Driving down the road the temperature gauge will read 165-170. On a nice spring day with the median temperature around 65-70 degrees the temperature gauge in the truck will read around 150 degrees contiuous driving. For stop and go driving the temperature gauge climbs up to around 160 degrees. The truck has its original radiator and a 50/50 mix of anti-freeze and water.

On my 1951 Chevrolet 2-door sedan, on a 100 degree day, stop and go, the temperature of the coolant will be around 180. Driving down the freeway the temperature of the coolant will be around 165. My 2-door sedan also still has its original radiator and it is running on a 50/50 mix of anti-freeze and water.

Based on what you posted above, I would say that on your truck is still running a little too hot on both scenarios.

:( :( :(

I agree JYD, should I get a new radiator and water pump or should I wait untii I get the heater going like Ray says?...Oscar

Well.......if you are going to do a lot of driving with the truck I would recommend getting a new radiator and water pump if you continue to have a heating problem. However, I would do what Raymondo suggested first so that you will know what you are looking at temperature wise with the heater connected before you spend the money to recore your radiator and install a new water pump. And, then you will also know what condition your heater core is in as well.

Thanks JYD, I'll do that...Oscar

:cool2:

One additional question, does the vehicle have an operating pressure radiator cap of around 7 pounds which is as I recall the original equipment requirement. That will do nothing about heating but will help control boiling and coolant loss.

Glyn, I think it is a 4 lb. I will check tonight
and if it is should I get a 7 lb.?...Oscar