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Discussion Starter · #1 ·
so i decided to change the waterpump sunday and been driving it with no thermostat, so when it sits or when i shut the car off the temp rises up to 230 240 i donno why do you think it could be the radiator
thanks
louis
 

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Did it run hotter before the w/pump was changed?
Not enough coolant as in needing to purge more air from the system,
Fan belt loose,
Idle RPM too low,
Radiator clogged, either/both, externally and internally - flush with garden hose,
Initial timing too retarded,
No fan,
Leaking head gasket - do a coolant lithmus paper check for exhaust fumes in coolant,

Had you not added the phrase "when it sits" and just said "when shut off," I would say this condition be normal due to heat soak - no air moving and engine soaks up heat.
But you said when sitting and I assume the engine is idling, so here are my suggestions.
Others might add more suggestions.
 

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Discussion Starter · #3 ·
i believe it was running hot before i changed the pump.
i bought the car with no functioning temp gauge dove it home 50 miles
when i got home i could see the top hose and hear some wising noise and bubbling noise when it cooled down i took the termostat and put a gauge it would run fine and heat up when idel or when i turn the car off, then i change the pump same issue then i change the radiator samething happen
i dont know now could it be head gasket
when it heats up my oil is kinda watery but not milkshaky
but when cold it looks normal
there is a fan from the pulley
when im driving the car it stays 190
when i idel for 5+ min it climbs cause the cars idel is low
and when i shut the car i climbs cause the water is not flowing
what is causeing this
 

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when it heats up my oil is kinda watery but not milkshaky
Good symptom of a bad head gasket.

A check of coolant with lithmus paper is a check and dirty check to see if exhaust gas is entering the coolant system.

Another check is remove the spark plugs, bring a cylinder up to compression, both valves closed, and inject compressed air into the cylinder via spark plug hole, view coolant in the full radiator for air bubbles from the compressed air. Repeat for the five remaining cylinders.

If air bubbles are present, need head gasket changed. Of course, with cylinder head off, it would be prudent to have the shop pressurize the head and check for cracks. If cracked, replacement head is needed.
 

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Classic blow head gasket or cracked head...
Do a HC test on the radiator...generally free at most workshops worth their salt.
And/Or pull the HT leads off and replace 1 by one...the one that doesnt have much or any change will be the bad one...then pull the spark plug...it will be noticably cleaner thean the rest...and if wish to go further...turn the engine so the pist is at the top on that cyclinder, with a torch u will notice the piston will be clean.

Classic blown head gasket m8.
 

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driving it with no thermostat

Biggest problem right there my friend, you need to slow the coolant down through the radiator so it has a chance to dissapate the heat.
Cut the guts out of the T Stat and reinstall the ring..
Problem solved
The rise in temp is normal after you shut it down,
With the T stat ring it should run about 160.
If you are running the temp gauge sending unit in the intake it will run hoter than in the head the gauge changes are more drastic at this location
 

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Replace the thermostat. The oil being thin when hot is normal. If it continues to be an issue I would then look into the head gasket or a cracked head.
 

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driving it with no thermostat

Biggest problem right there my friend, you need to slow the coolant down through the radiator so it has a chance to dissapate the heat.
If slowing the flow of coolant would cool the engine better, a thermostat would close instead of open when the engine gets hot. In the real world, the slower the coolant flows the hotter the engine will get, which is why a thermostat opens and allows more coolant flow as the engine gets hotter. The radiator is most efficient at dissipating heat when it is as hot as you can get it, which means circulating the water as rapidly as possible.

You most likely have a low flow problem, either air or coolant.

Here's some good information on cooling:

http://www.arrowheadradiator.com/technical_articles.htm
http://www.arrowheadradiator.com/Why_is_my_car_overheating.htm
http://www.arrowheadradiator.com/14...apability_in_high-performance_automobiles.htm
 

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I read an article written by an engineer about not running a thermostat in older engines and it stated something about the engines were designed to have the water flow stop every now and then so the water in the back of the block and in other pockets can be cooled. He stated that if you run without a thermostat the water will just flow in the front of the block and you will have hot spots, he backed it up with some real world tests. Made sense to me at the time, wish I could find it. So maybe the location of your temp sensor is in one of those hot spots.
 

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I read an article written by an engineer about not running a thermostat in older engines and it stated something about the engines were designed to have the water flow stop every now and then so the water in the back of the block and in other pockets can be cooled. He stated that if you run without a thermostat the water will just flow in the front of the block and you will have hot spots, he backed it up with some real world tests. Made sense to me at the time, wish I could find it. So maybe the location of your temp sensor is in one of those hot spots.
How does stopping the flow cool anything? If I'm standing in a cold river, does the water need to stop to make my feet cold?
 

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How does stopping the flow cool anything? If I'm standing in a cold river, does the water need to stop to make my feet cold?
From what I recall he said that the pockets of hot coolant would remain untouched by the flowing coolant but once the flow is stopped and placed under additional pressure the coolant temp in all areas of the motor would balance out. Like I said not my theory, made sense at the time though. If the coolant in the back of the motor never passed through the rad then it would never cool. If the coolant passages on a motor are designed so the coolant flows in one side and out the other like pipes than I can see no thermostat would be needed except to allow the engine to heat up faster. But if the coolant flow is not directed as such and can pool in areas of the motor then it will not cool as efficiently.
 

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I read an article written by an engineer about not running a thermostat in older engines and it stated something about the engines were designed to have the water flow stop every now and then so the water in the back of the block
You are correct, and Smokey Yanuck covers this very well in his books...And also i have many yrs experiance in real life on several olders cars where the cooling systems are way over built
This debate comes up everyso often...One side we have the therorists and all their therory links and Einstine formulas. on the other side hands on practical people, who dont have 1/2 doz PhDs after their name experts who know what happens in the real world, but international reputaions are legend engineers and race car drivers....

So choose you side...therory or real world.

Here is a theory...If u dug a hole thru the world and jumped in...would u fall out the other side?
The therorist says no...u will accelerate to the center and slow down to the otherside, wheregravity will again draw u back aceelerate to the center, slow down...like a pendulum
Correct?
Hell no...say the real world people...u will not even get to the center
As u get nearer to the center it gets hot and u will burn up ......
 

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First off - in the "real world" the flow of coolant never stops once the thermostat opens. It doesn't open and close in a cyclic manner as the hysteresis in the operation allows it to find some stable partially open position that depends on the operating temperature of the engine.

The thermostat does not direct the flow of water, it is basically right in line with the radiator inlet after all the coolant has been collected at the front of the manifold. The device that most affects the distribution of coolant is the head gasket, since the coolant must all flow from the block through the holes in this gasket into the head for return to the radiator.

Let's say that your water pump is operating at 50 gpm and you have 5 gallons of coolant in the system equally divided between radiator and the block. This means that every six seconds all the coolant you have is pumped through the system, three seconds in the block and three seconds in the radiator. It is actually worse than this because of the hoses and tanks that do little to help the cooling cycle.

Stewart Components, a "real world" manufacturer of cooling system components has some great info on the effect of low flow, radiators, etc.

There are five tech tips plus very interesting additional information.

http://www.stewartcomponents.com/Tech_Tips.htm
 

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Many years ago before I did anything to my engine
l had a tough time keeping it cool at slow speeds and idle. I replaced the rad, multiple thermostats, heater core, water pump and what ever else i could think of.

One of my technicians suggested that I flush the engine block.
Using an air powered power flusher. An incredible amount of crud came out. Now with a 180 degree thermostat it never breaks 195 on a hot day in traffic when going nowhere.

I can't say that it will work for you, but it is an inexpensive option.
just be sure to disconnect the rad completely. Rads hate air pressure.

Paul :beers:
 

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First off - in the "real world" the flow of coolant never stops once the thermostat opens. It doesn't open and close in a cyclic manner as the hysteresis in the operation allows it to find some stable partially open position that depends on the operating temperature of the engine.
Actually it does open and close just like that in a first gen motor.
 

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Actually it does open and close just like that in a first gen motor.
Correct ...
No thermostat ..well no thermostat housing restiction the it will run hot because to fast thru the radiator and the exit from the radiator is still hot into the engine...the restriction prevents this as previously discussed


Let's say that your water pump is operating at 50 gpm and you have 5 gallons of coolant in the system equally divided between radiator and the block. This means that every six seconds all the coolant you have is pumped through the system, three seconds in the block and three seconds in the radiator. It is actually worse than this because of the hoses and tanks that do little to help the cooling cy
Yep cant gespute the maths....but the theroty and that is what it is way off.
1/50gpm at what head? none head is the resistance
2/ There is the resistance in the thermostat housing then less restiance in the radiator (assuming clean un blocked radiator)
Throw those parameters in the the maths and therory goes out the window.
 

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Understand all the theories...now I"m really confused. Assuming the overall cooling system is in pretty good shape, would a 350 V8 run cooler at low speed with a higher flow water pump (and associated thermostat) or run cooler with the standard water pump. Use the Stewart Stage 2 pump and modified Shaw thermostat for this hypothetical example.
 

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(and associated thermostat) [/QUOTE
Neather iy will run at the thermostat temp Starts taking colder water in thermostat wide open, water doesnt reach thermostar tem the thermostat closes up (or partly does)
And visa versa as conditions change like going up a moutain and rarified air or between ruch hr traffic and then hitting open road....

Running with a thermostat housing no ( thermo part) it will run cold, the resitraction has been pre calcuated to always have a gph flow to do tthis...which happens to be an import spec of any cars thermostst..noy just the opening rate.
 

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Assume the thermostat is open....assume we are running at about 190 deg, with a 180 thermo already open.... Will the system cool quicker with a high flow water pump vs a factory pump?
 
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