No thermostat ? - Chevelle Tech
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post #1 of 46 (permalink) Old Jun 15th, 12, 12:51 PM Thread Starter
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OLIVER
 
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No thermostat ?

Hello everybody...
had a problem with the waterneck and changed the o-ring , in the meanwhile I noticed that I was without a thermostat not sure why , but the car never ever went past 190

So I installed a 160 stat , today is 86F , i m running to hot ? 200 cruise and 220 at idle creeping up to 230 in heavy italian traffic.

Should I worry ? remove the thermostat and install it only at beginnig of winter ?

(ps the car came from Dallas)
Thanks

Oliver
Milano , ITALY

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1969 396 SS monaco orange (72)
468 Vortecpro 585 HP back to street cruiser
M20 4 speed - 3.31
Prosystems 1000
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BEST MPH 121
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1969 El Camino Street Strip
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BEST ET 10.67 @ 127 1.56 60FT
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post #2 of 46 (permalink) Old Jun 15th, 12, 1:19 PM
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Re: No thermostat ?

I can think of two possibilities. The first is that your new thermostat is defective. Put in a pan of water on the stove. See what temperature opens it, if it opens at all.
The second possibility is that it is installed inverted. The sensor part of it should be at the bottom.
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post #3 of 46 (permalink) Old Jun 15th, 12, 2:16 PM Thread Starter
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OLIVER
 
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Re: No thermostat ?

2 more questions
How hot is too hot ?
why was the car without one ?

Oliver
Milano , ITALY

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1969 396 SS monaco orange (72)
468 Vortecpro 585 HP back to street cruiser
M20 4 speed - 3.31
Prosystems 1000
BEST ET 11.62 (with 4.10)
BEST MPH 121
BEST 60 FT 1.64
4000 lbs street car


1969 El Camino Street Strip
467 Vortecpro Tunnel ram 730+ hp TH400
BEST ET 10.67 @ 127 1.56 60FT
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post #4 of 46 (permalink) Old Jun 15th, 12, 3:08 PM
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Re: No thermostat ?

Quote:
Originally Posted by oliver69 View Post
How hot is too hot ?
Two measures of "too hot".
1. Engine temp is so high that it can cause damage. This will probably involve temperatures over 220 degrees. The "HOT" light on the dashboard it typically triggered by a switch that closes at or above 240 degrees. In any event, if the coolant is BOILING, the engine is too hot.

2. If the engine temperature at idle or cruise is more than ten or fifteen degrees above the thermostat rating, the thermostat has lost control of the coolant temperature. This can be from many root causes; typically a radiator that doesn't have enough heat-rejection capacity; missing cooling-air ductwork, a fan system that's under-sized or defective, or an engine so far out of tune that it's creating excessive heat.

You're looking at #2. Your engine isn't hot enough to cause damage, but the cooling system cannot handle the heat generated, so the temperature climbs well beyond the thermostat rating during ordinary driving.

There are one or more problems; you haven't found it/them yet.

Quote:
Originally Posted by oliver69 View Post
why was the car without one ?
The usual reason for removing the thermostat is that the owner is too lazy to find the REAL cause of excessive temperature. I guess that happened to you, prior owner yanked the 'stat rather than identifying and fixing the true cause.

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post #5 of 46 (permalink) Old Jun 15th, 12, 3:15 PM
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Re: No thermostat ?

Oliver, first, make sure exactly what temp the car is running at-a 40 yr old guage is not accurate. If its not a factory guage your looking at then where is the aftermarket guage getting its signal from? (Intake or the head) You can buy a laser heat gun for less than $30 from harbor Freight though by the time it gets there you'd be at close to $80.
Try idling the engine with radiator cap off for a while till its good and hot (be carefull to start with coolant level at least 2 inch below neck)then stick a candy thermometer down the radiator neck and see what it really is-you'll be suprised. It will either be way hotter than what guage says or way cooler. Mine was off almost 25 degrees cooler.

A thermostat has nothing to do with how cool the engine runs it only controls flow of coolant. A 160 degree TS wont make it run at 160 in other words. Needless to say you've got some diagnostic work to do but we will help you so dont worry.

What ever you do remember that your car needs a thermostat and it will not oveheat overheating-an engine thats not hot enough or one that takes a long time to warm up is as bad as one that overheats.

I would start with what was already mentioned by testing the 160 TS you bought. Then move on to items like engine timing, proper fan and fan clutch, proper shroud, good radiator, good water pump etc. But if it was supposedly running at 190 before you put a TC in then it probably is a defective TC.

As for why a TS was not in there-who knows-could have been masking a bigger issue to sell the car but i hope not.

Marc S

Last edited by 1971ss454Elco; Jun 15th, 12 at 3:34 PM.
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post #6 of 46 (permalink) Old Jun 15th, 12, 4:20 PM Thread Starter
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OLIVER
 
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Ok guys thanks for all the info , i will check again all the points you mentioned - starting with the stat and then the aftermarket gauge and so on

What about the coolant ? Since I had a leak I added just water, so I think at the moment I have more water in %
What is the correct %
Could it be also a cause of the quick rise in temperature ?




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Milano , ITALY

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1969 396 SS monaco orange (72)
468 Vortecpro 585 HP back to street cruiser
M20 4 speed - 3.31
Prosystems 1000
BEST ET 11.62 (with 4.10)
BEST MPH 121
BEST 60 FT 1.64
4000 lbs street car


1969 El Camino Street Strip
467 Vortecpro Tunnel ram 730+ hp TH400
BEST ET 10.67 @ 127 1.56 60FT
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post #7 of 46 (permalink) Old Jun 15th, 12, 10:06 PM
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Kev
 
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Re: No thermostat ?

50/50 coolant to water is typical.
The thermostat doesn't regulate engine temp unless its not opening (defective), or the opening temp is just below operating temp, and it opens and closes. The latter is unlikely.

The thermostat helps the engine warm up by not opening until the engine is warm. After that it stays open. When running w/o a thermostat, its possible that the lack of restriction of the open thermostat allows coolant to flow through the rad too fast, and not be cooled.

sounds like you have a fan, or shroud problem.
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post #8 of 46 (permalink) Old Jun 15th, 12, 11:03 PM
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Re: No thermostat ?

If the temperature sending unit has been replaced with a new one chances are it is not reading right.

Verle
Tulsa, Ok
65 Chevelle L79 since Feb 1965


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post #9 of 46 (permalink) Old Jun 16th, 12, 12:25 AM
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Re: No thermostat ?

don't worry about the % coolant deal. plain water is actually the best coolant, but it gets rusty, freezes and boils at a lower temp than 50/50.

Also, have to make sure the system is actually full, guys have been tripped up by air trapped in the block. I drill a couple 1/8" holes in the 'stat so air can bleed out.

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post #10 of 46 (permalink) Old Jun 16th, 12, 12:36 AM
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Re: No thermostat ?

Tom, insert a smiley or something to indicate sarcasm
Not everyone gets that humor...
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post #11 of 46 (permalink) Old Jun 16th, 12, 1:23 PM
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Re: No thermostat ?

Quote:
Originally Posted by 66sc View Post
.... When running w/o a thermostat, its possible that the lack of restriction of the open thermostat allows coolant to flow through the rad too fast, and not be cooled......
I disagree on this way of thinking and here is my reasoning.

The speed of any amount of coolant going through the rad is the same
no matter how much volumn of coolant is in the rad
as the speed at which the belt driven water pump turns/pulls the cooler coolant
from the rad and back into the engine's flow of coolant
is always the same as it is based on the engine's RPM.

Most engines in our cars will run a temp of 180* or higher,
after they have been warmed up before going out onto the hwy.
If the coolant is hot when it comes to its possible exit point on the top of the intake manifod,
and the amount of coolant to exit is restricted to the rad's inlet by a thermo stat
then the more volume of hot coolant that stays in the engine is then heated even more
as it goes back through the engine's flow passages to come back again even hotter
than before where it is restricted again thus allowing only a small amount
to be routed through the rad for cooling.
With no thermo stat there is a greater amount of coolant in the rad
at all times and thus more of it being cooled at all times.

Since we/most of us only drive our old cars in relatively warm times
(Spring/Summer/Fall) a thermo stat is not really required !

Last thought, how many race cars/engines run a thermo stat, whether it be road or drag etc.

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1/4 = 11.814 et / 115 mph
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post #12 of 46 (permalink) Old Jun 16th, 12, 5:35 PM
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Re: No thermostat ?

Assuming your fan & fan clutch are working properly, I would say that the radiator needs to be cleaned & rodded out, re-cored, or even replaced...

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post #13 of 46 (permalink) Old Jun 16th, 12, 5:41 PM Thread Starter
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Thanks for all the imput - I will sort this out ...
By the way heavy traffic I mean driving 2 mph for 30 min in first gear -stop -first gear stop etc etc one car after the other - through the city at 86- nightmare !!!!


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Oliver
Milano , ITALY

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1969 396 SS monaco orange (72)
468 Vortecpro 585 HP back to street cruiser
M20 4 speed - 3.31
Prosystems 1000
BEST ET 11.62 (with 4.10)
BEST MPH 121
BEST 60 FT 1.64
4000 lbs street car


1969 El Camino Street Strip
467 Vortecpro Tunnel ram 730+ hp TH400
BEST ET 10.67 @ 127 1.56 60FT
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post #14 of 46 (permalink) Old Jun 16th, 12, 6:03 PM
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Re: No thermostat ?

Quote:
Originally Posted by oliver69 View Post
Thanks for all the imput - I will sort this out ...
By the way heavy traffic I mean driving 2 mph for 30 min in first gear -stop -first gear stop etc etc one car after the other - through the city at 86- nightmare !!!!
Shouldn't be a problem. When the cooling system and engine is functioning properly, you'll be at or very near the thermostat rating under those conditions.

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post #15 of 46 (permalink) Old Jun 16th, 12, 11:34 PM
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Re: No thermostat ?

Quote:
Originally Posted by Kirk's67SS View Post
I disagree on this way of thinking and here is my reasoning.

The speed of any amount of coolant going through the rad is the same
no matter how much volumn of coolant is in the rad
as the speed at which the belt driven water pump turns/pulls the cooler coolant
from the rad and back into the engine's flow of coolant
is always the same as it is based on the engine's RPM.

Most engines in our cars will run a temp of 180* or higher,
after they have been warmed up before going out onto the hwy.
If the coolant is hot when it comes to its possible exit point on the top of the intake manifod,
and the amount of coolant to exit is restricted to the rad's inlet by a thermo stat
then the more volume of hot coolant that stays in the engine is then heated even more
as it goes back through the engine's flow passages to come back again even hotter
than before where it is restricted again thus allowing only a small amount
to be routed through the rad for cooling.
With no thermo stat there is a greater amount of coolant in the rad
at all times and thus more of it being cooled at all times.

Since we/most of us only drive our old cars in relatively warm times
(Spring/Summer/Fall) a thermo stat is not really required !

Last thought, how many race cars/engines run a thermo stat, whether it be road or drag etc.
The cooling effect of the radiator is determined (in part) by the time the coolant spends in the radiator, and the time spent in the engine. In the former, its transferring heat to the rad; in the latter, its transferring heat from the block to the coolant.

The time the coolant spends in contact with each surface is significant. Go stand outside naked in the winter for 30 seconds and then again for 30 minutes. Which one made you colder? 3rd grade science at work here

Certainly other factors are significant, but let's start where the existing system deviates from as designed...
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