The Stovebolt Site Forums The Shop Area Engine Shop over-temp problem with '46 1/2T with '55 235 eng.

When I had first assembled my project to the point of starting the engine, I found that it took only a few minutes to overheat. Knowing that it had the original radiator which had a few leaks repaired with stop-leak, I decided that the least expensive, easiest trouble shooting approach would be to replace the radiator with a new radiator. Let met add, do not choose RadiatorExpress (I hope that opinion does get me banned). After compensating for a 1946 radiator that did not fit a 1946 truck. After getting all back together, I started the truck.

Now, here is where I would like some input. I had intentionally left out the thermostat. I had it in neutral, at idle. I had it running for maybe 15 minutes, noting that it took a while for the temp to make it up to the 180 mark, at which point I shut it down. Is this about what I should expect? Is it still running hot, even though better? If so, what next?

Bob

Put the thermostat back in...you could be flowing coolant to fast through the Radiator and not letting it do it's job!

Don't forget to stove top test the thermostat first to make sure it opens.

Mike B

Here is my take on a particular engine which overheats when the thermostat has been removed. That particular engine has another reason for overheating than whether or not it has a thermostat in place.
To answer your question about the engine taking a long time to heat up to 180 without the thermostat. That should be expected. A more significant question would be what would the temperature have been if you would not have shut it of as soon as it reached 180.

My well-tuned and in good shape high-pressure 235 engines would never warm up to 180 degrees without a thermostat (simply idling in my 50-60 degree garage).

Well when I had an overheating problem it was timing, retarded to much, might check that?

A couple of factors are in play here. A thermostat sets the MINIMUM temperature a cooling system sees by restricting coolant flow until its opening point is reached. It's up to the radiator, the fan, and the water pump to maintain that temperature once the thermostat opens and coolant starts circulating. Idling is a poor way to evaluate cooling system performance- - - -neither the water pump nor the fan is turning fast enough to be efficient. Install whatever temperature thermostat cranks your tractor- - - -I prefer a 180, and set the engine speed up to around 1500 RPM with the idle speed screw to see where the coolant temperature stabilizes, or do it the right way and take a test drive. I'd recommend using a laser thermometer to check various places on the engine block, hoses, and radiator core to see what's actually happening- - - -a dash-mounted temperature gauge is a wild guess at best.

If the coolant isn't boiling, the engine is not overheating.
Jerry

I'm running a later 235 engine also, trouble is water pump/fan location, much lower that the original, I installed an electric pusher fan up high on the radiator problem solved. There are better fixes now with the adaptor plate so you can run original w/pump up where it belongs. Best of luck

BobS46,

What year engine do you have in your truck ("'55 235 eng").

1955 1st series or 2nd series?
What is the engine serial number pressed into the block behind the distributor?

I hope this gets viewed by both JiMerit#43 and tclederman -

TC - no idea what series - serial number looks like 016II95F55Z

JiMerit - having done some investigating into comments made in this thread, is beginning to look like I might have normal performance, running hot because the fan is sitting so low on the radiator. I would like to know what fan you are using.

Bob

Bob, I picked up a generic fan at the local PepBoys several years ago and just run if off a toggle switch, can also be run by a theomostatic switch. I will try to find the brand name and get back to you.
Assuming your 235 is the most common style (2nd series) with the water pump lower in the block vs the early style with water pump up under the thermostat housing,
Note: my 46 only boiled over in the summer time and mostly in traffic also I'm running a radiator from a 2 ton truck, a giant compared to the half ton rad. During nice weather I do not need to switch it on.

This is the brand of fan I used, link to Summit racing. These come in several sizes, get the fan that fits your radiator best. I mounted the fan up high to the front as a pusher, a puller may also work by itself, may need to remove the stock fan for clearance.

https://www.summitracing.com/parts/...-_-shopping-_-srese2-_-hayden-automotive

I have a 49-3100 with a 55-235 engine. Water pump and fan are lower to the radiator. I installed a 17 inch 6 blade fan and used spacers to locate close to radiator. I used a Robertshaw high flow 180 thermostat and the motor runs at 180 degrees with no over heating issues.

Be careful, if the spacers are single items, vibration might kill them. Find a friend with a lathe or mill, and make a solid plate with your bolt pattern and thickness to install, Al would be fine.

Many engine configurations allow the temp to open the t'stat. at some stated temp shown on the guage(220) then cool down to some static temp that is tolerable(180). My 503 is this way since original t'stats no longer available, put in radiator down pipe.

Ed

You are right. I made spacer in my shop to fit. All I can say is the 180 Robertshaw thermostat has has worked great. Engine runs great at 180.