The Stovebolt Site Forums The Shop Area Engine Shop thermostat degree for a 235

So what temp should I get for a 56 235. I am leaning toward a 160. The 180 I have seems to be to high.

Thanks

180 is fine but check your cap. Why does it seem too high? The 160's were used primarily because of so much alcohol basd anti-freeze used back in the day. 200 won't hurt it. Think of how high the modern engines operate. If your radiator is flowing well, cap is good and coollant is clean your good to go.

moneypit....you da man

So I had a 180 in it but it keeps overheating and spitting out of the overflow. So I took it out and it ran fine. Is it just opening too late. I am only running it with water no coolant. Would the coolant make that much of a difference or should I get a 160. The pump works and the thermostat works boiled it on the stove. What do you all think. Why is this happening.

might be stucked.......I wouldn't think a 20 degree higher one would cause it to over heat,,, can you put one of these in backwards.. on some vehicles you can, by taking it out and it runs ok,, I would think that would tell me that something is wrong with it, but not sure about 160 vs 180.. how long does it take to get that hot where it boils out..

they are cheap so I suspose you could just swap them out and see........mine runs 180 when it is warmed up,,no problem with it..

My dad once had a 1953 Chevy sedan stovebolt. He ran 160 in the summer and 180 in the winter. Hope this helps.

The 160/180/195 thermostat rating refers to the degrees when it is fully open. It starts opening about 20 degrees earlier.
Best thermostat I found is the 'Mr. Gasket - high performance' type which is a better and smarter design which has least restriction when open.
It also stays open in case it ever gets stuck, unlike conventional types which would stay closed. Only a couple bucks more than standards.

Thermostats are there to provide the minimum temp the engine needs to run most efficiently with the least wear.
235 manuals recommend 180. Some think they run best around 200.
Once the coolant temp reaches 180 degrees, a 160 will be just as open as a 180 with the same flow - Meaning above 180 degrees a 160 will not cool the engine more than a 180 !
Especially in the colder months a 180 thermostat helps with warmup time and burning off harmful water vapor inside the crankcase when doing short runs.

If you get best results running straight water and no thermostat - your radiator or hoses are probably clogged (hopefully not the block) and it probably needs a recore.

Try first using a motor flush cleaner (or 4 gallons of vinegar from the 99c store soaking overnight) and then flush reverse from the petcock side with a water hose (on the drivers side next to the gas pedal linkage).

You can try flushing the radiator with DILUTED muriatic acid (or straight concrete cleaner from the hardware store).
But it's really ALWAYS best to get a recore or new radiator, if you have the funds.
Go for a 3 core type minimum and if funds are plenty also use Evans NPG+ coolant which is completely waterless and the best thing you can do for your cast iron engine, radiator and hoses in the long run.

Used or old radiators without known regular flushing history will almost always be clogged - water loves to corrode them sooner or later, even with 50/50 mix of glycol based antifreeze coolants. Regular flushing only slows down the corrosion.

Raw metals and water regardless of dilution or additives should never really be together. It's simply cheap and user friendly.

You should not run it with no thermostat, the thermostat act as a flow regulator. Without one, the coolant flow is too fast, and will not be able to exchange the heat out to the radiator effectively. If you don't use a t-stat, you can put a fender washer in the neck to slow the coolant flow down to an acceptible rate. That's an old Flathead trick. Personally, I think that a 180 t-stat will be fine, used witha 50/50 antifreez/coolant mix. Something most people forget is that "antifreeze" is also a coolant. It actually raises the boiling point of the water in addition to lowering the freeze point. It also has anti-corrosion additives in it. I'm running a 50/50 glycol (green) mix with a 160 t-stat and a bottle of Red-Line Water Wetter, the '55 runs around 170, a little higher in traffic.

i ran a new 195 and seem to run to hot so i changed to a 160 and it is a little low. i have a new radiator so there is no problem there. so it seems the 180 should be the best choice. will put the 195 in this winter and see. ron

LONGBOX55 is right-on with the fact that you need some restriction in the flow. On all vehicles the cooling system was designed around a certain volume of coolant passing through the system at a certain rate. If the rate of flow through the system is increased then the coolant might not have time cool enough; especially under certain condition. I have seen this many times where the driver complains about overheating when stuck in slow traffic on hot days. The coolant passes through the system too fast to cool down and gets hotter and hotter. Almost every time I find that the guy has removed the thermostat and if I convince him to put a thermostat back in then the problem goes away. I have had this argument many times and still have lots of people who will not believe. Under some driving conditions the problem is minimized but stuck in traffic on a hot day is the worst.

"On the road again" touched on something that most folks don't consider when trying to get their engines to run "cool".

Cylinder bore wear is accelerated each time you drop your engine operating temperature by five degrees. I learned this the hard way with an engine that I ran ultra-cool and had to rebore at 40K. In addition, lower operating temperatures are often the culprit when you find an engine that is all sludged up.

If you look at today's engines running 100-150K without even a valve job and at normal temperatures at or above 195 degrees, and meeting or exceeding emissions requirements, it indicates to me, that heat is not the enemy we were lead to believe.

A quality thermostat as "On The Road again" points out, along with a good efficient radiator, and a 50-50 mix of antifreeze and DISTILLED WATER is going to save you money down the road. An extra couple of bucks is pretty cheap insurance when the cost of an engine is at stake. Just my $.02 because.....

I agree, thermostat or hoses. To check the thermostat just put it on top of the stove heating element and see if it opens up or not. Even this may be deceptive as I have had a couple in my day that would stick, then open, then stick. Once had a 62 impala 327 that would do that and I could tap on the t-stat housing and it would open. A good way to check the hoses is when it get hot some hoses that appear to be ok will actually "suck together" as the heat rises. Just adding more causes and effect to the same situation!!

So with all the above info what I didn't get or just missed, is what temp should the truck run at for optimum performance. should the guage read 180 or so?

So I put a 160 in and it seems to be working fine. We'll see how it does on the road.

I'm using a 180 in my 261. No problems at all moving home an entire cord of firewood in 95 degree weather yesterday. (Truck bed + 5x8 trailer) I run a stock size new radiator with an electric pusher fan in front of the radiator. No mechanical fan. My temperature gauge runs slap in the middle of the range, and only soaks up to 200 if you shut it off hot and leave it in the sun for a while.

If I remember right my shop manual says 160 for alcohol and 180 for modern antifreeze.

I run a 180 in the summer and a 195 in the winter here in North East Texas. I drive a 62 1/2 ton Chevy with a rebuilt 235 six and often pull a small two wheeled trailer. The main thing I try to do is keep the radiator clean by flushing or rodding it out and changing the anti-freeze every two or three years. I am running a rebuilt waterpump and the regular fan . We have had a full month of 100+ degree days this August and I had no overheating problems...