How crucial is a thermostat, really?

[Cap'n Hook]

Today, I decide it's time to replace all the coolant hoses and the thermostat. So I flush the radiator and take off the thermostat housing. And to my amazement, there's no thermostat!

Bought the truck from a guy in Waco about 18 months ago, he never mentioned it needed one. And I drove it all summer last year, and it made it through one of the hottest, driest summers we've had in a long time. I had always watched the temp gauge start edging up towards the 200 mark, but just figured, the thermostat was stuck open. Never would have guessed it wasn't even there.

Tomorrow, I'm going to pickup all the new hoses, cap, and thermostat. So, any ideas as what part number is for a GM Goodwrench 350 for a 175 degree stat?

Actually, a little bit of me, last summer, wanted the motor to cry uncle, just so I could give the wife and excuse to go through it!

[RckyMntnKng]

Correct me if im wrong, but I always thought a T-stat stays closed (No coolant circulating) until it reaches the temp rating it needs to open and let coolant into the motor / out to the radiator / and cool back down.

IE - If you have no T-stat at all then your engine is constantly circulating and cooling and in a hot dry summer over 100 it would be open all the time anyway if actually installed and working.

Without a T-stat it would definately take longer to get the motor up the correct and best operating temp and heater etc if you lived in a cooler place.

[VanceH]

I had an old 57 that ran hot during the summer when i was a kid, my dad told me to pull the therm during the summer and i ran that truck for years that way?, in the winter i had little to no heat.

[71swb4x4]

I don't know if this could ever be an issue, but if you have no thermostat, would it be possible to push water through the radiator too fast? Fast enough that the radiator isn't cooling the water thoroughly?

[Critter]

I know people up North don't do it because of the infective heater issue, but I have done it on numerous old farm trucks over the years and never had any issues. They stay cool in the summer and heat up plenty good for our winters. It might not do you any good, but on a carbureted engine I'm pretty sure it would never hurt anything.

[Longblock]

Originally Posted by 71swb4x4

I don't know if this could ever be an issue, but if you have no thermostat, would it be possible to push water through the radiator too fast? Fast enough that the radiator isn't cooling the water thoroughly?

It is a bad idea not to run one......I didn't have one in a Drag Truck I owned...but, it only went down the track..nod idling in traffic. The water in the radiator will not have time to cool... You can run em' w/o one but I wouldn't do it with something I drive on the streets.....

[Cap'n Hook]

Originally Posted by RckyMntnKng

Correct me if im wrong, but I always thought a T-stat stays closed (No coolant circulating) until it reaches the temp rating it needs to open and let coolant into the motor / out to the radiator / and cool back down.

IE - If you have no T-stat at all then your engine is constantly circulating and cooling and in a hot dry summer over 100 it would be open all the time anyway if actually installed and working.

Without a T-stat it would definately take longer to get the motor up the correct and best operating temp and heater etc if you lived in a cooler place.

I believe you are correct. But the only limiting factor, as stated above by 71swb4x4, is that the water gets pushed through the radiator so fast it doesn't get cooled and is then fed back into the hot engine where it does no good to cool down the internal engine temperature. Having a functional thermostat is definitely a necessity on a daily driven (summer time only) vehicle.

[Tom Vogel]

Run the thermostat and continue to service your cooling system.

[Cap'n Hook]

Today I got $153 worth of parts, including a 180° t-stat, upper/lower hoses, new cap, t-stat housing and coolant, and 4 new high/low beam headlights installed. Hopefully that will cure the ups and downs of the temperature curve this summer!

[elks]

Run it. The person that said those north do not use them is wrong. Usually we run the warmest one we can find. We also tend to use some cardboard to slow the cooling down in the coldest points.

The thermostat is necessary to keep the engine running at optimal temps. As mentioned, no thermostat may run it too cool.

Also longer engines from front to back are said to have really wild temp issues without a thermostat. I have read that the AMC inline 6 258(popular jeep motor) will burn up the back cylinder if it is ran too long without a stat because the t stat is needed to create enough pressure to send the fluid all the way back to the rear of the block.

[Critter]

Originally Posted by elks

Run it. The person that said those north do not use them is wrong. Usually we run the warmest one we can find. We also tend to use some cardboard to slow the cooling down in the coldest points.

I think you are talking about my first post and I think you misread it. I said that people up north don't do it as in they don't REMOVE the thermostat. I then went on to explain that the heater won't work properly in those conditions without one.

Anyway, I am a little confused CapnHook, you start this thread by asking the question how crucial a thermostat is, then in post 7 you answer and say that it is "definitely a necessity". I'm not trying to be rude but I'm confused why you asked in the first place??? Maybe I misunderstood something, it happens to me quite often.

Also, I stand by my original statement. When I first read this question I took it to ask how crucial is a thermostat in South/Central Texas. I will answer it again the same way, I don't feel that it is "crucial" to a decent running carburated 350 in our part of the world. I DO feel the same way as others that it is in the best interest to run a thermostat in a daily driver, BUT I have yet to hear of a truck around here having ANY damage by NOT having one. If someone has heard of a small block Chevy (in these climates) having troubles due to this I would love to hear about it for my own knowledge.

[elks]

Originally Posted by Critter

I think you are talking about my first post and I think you misread it. I said that people up north don't do it as in they don't REMOVE the thermostat. I then went on to explain that the heater won't work properly in those conditions without one.

Your right, now that I read it I realize what you were saying.

[Jacfourteen]

I agree, not crucial, but definitely recommended.

[71RestoRod]

You always want the engine running at temp. A cold motor is less efficient but more concerning is the condensation that tends to build up inside the block, creating sludge, rust and generally speaking an unhealthy operating environment.

It's also true that engines can run cooler with thermostats installed. It just depends... I've seen this first hand with flathead Fords which are notorious for running hot. The water pumps circulate coolant so fast that the radiator doesn't have a chance to do it's job. We slow down the flow by installing thermostats, restrictors, etc. I've seen some guys get the best results by cutting back the impellers on the water pumps.

[Cap'n Hook]

Critter, I guess I asked the question in the first place to bring up the importance of the thermostat in an engine. More of a rhetorical question! Didn't mean to confuse anyone, but some people don't realize how the cooling system actually works, possibly?

Because my engine didn't have one, the coolant wasn't actually able to cool the engine in the correct way it was meant to, had it had a thermostat installed! I still stand by my statement that it is "definitely a necessity" in order to hold steady the coolant temperature, rather than have the instability of running without one. If you have ever driven the Hill Country area north and west of SA on hot 100 degree plus days with A/C, you'd consider a thermostat "definitely a necessity" as well.