hot hot hot

[offroader-rama]

hello all, , i just put a set of extactors and a new head gasket on my GQ patrol tb42 , I replaced the temp sender and i had head machined, now temp gage says that the temp is just over half, for the last three years its said less than a quarter, i also put brand new v8 radiator in ( planning ahead ), so i thought it would run colder if any thing so i cut the thermostat up, put it back in road test, same, so pulled the water pump off, all good there, tripple checked timing,@ 10 degrees all good.
so ive come to the conclusion that the old sender may have being reading wrong where do others gq's temp gage's sit.
I dont want another blown head gasket or worse so close to christmas to gamble.

thanks

[chops]

my temp gauge always sat half way once warm.. never budged otherwise

[CruiserPatrol]

My temp also sits just under the middle and moves slightly up under load when the fan cuts in.
Is your fan clutch working correctly?

Dave

[offroader-rama]

yes my fan does works, but if it didn't I'm testing it on a hwy, so the wind a lone pushing through a v8 radiator should be plenty, does any one else not run a thermostat, I'm wondering how it'll go of road with out one, to hot or cold

[chimpboy]

Sitting at half sounds fine. Mainly what you want to watch for is, does it get up to this point fairly quickly, and then sit there solid as a rock no matter what you do or what the outside conditions are?

If so, then you have a good cooling system.

If it goes up and down a bit with heavier driving or hotter ambient temperatures, your cooling system is marginal and you should look it over.

Did you say you are running the engine without a thermostat? This is plain stupid.

[Ezookiel]

Mine has cooling issues in bucket loads,
but on a very hot day yesterday with a reasonable load on board, and air-con on full, it varied from a touch below the half, to a touch over the half depending on hills. That's the best I've had from mine for a while.

But then it's BIG hills that kills mine, and I didn't dare do any of those, I'm too scared to risk losing my car for work again this close to Christmas. I need the money.

[offroader-rama]

[quote]Did you say you are running the engine without a thermostat? This is plain stupid.[/quote]
I'll pretend you said very unwise chimpboy as for stupid how many race cars dont run thermostats and they go through a hole lot more flogging than i give mine ok i little more flogging than i give mine ok the same i admit it but the point is they still racing they work out what size restricker to replace the thermostat and thats that

and ezookiel Ive seen you in other furums looks like your sharing some of my luck lately chin up christmas will be over soon enough i'm holding out too dont feel alone I'm saving up to put a 383 chev in mine but keep pumping money into the 6 to keep it going till i've collected everything i need to finish it was going to be my christmas present maybe my easter egg now.

[vorno_18]

the problem with running no thermostat is it will stay cool around town but going down the highway for extended periods will cause it to heat and get very hot

the waterpump will be pumping the water around fast at highway speeds about 2500-3000rpm and will pass through the radiator very quickly not taking off much heat and it will just build up and get hot

[offroader-rama]

thats why for this exisize, i cut the guts out of the thermostat putting the outer ring back to restrict flow, just to rule out wether it was faulty, it had a few rust deposits so i wanted a new one to be safe any way.
when i get up it, the temp needle moves from half to just over then stays I havent tried with air con and off road or a longer than 20 km trip yet if it doesnt get hot I might leave it.
After 2 thermostats failing in my monaro I drove it for 6 years without a thermostat (i left the outer ring in) and never had problem again always sat on quarter.

[bogged]

my temp sender was fucked, but they are $$$ from nissan...

[chimpboy]

the problem with running no thermostat is it will stay cool around town but going down the highway for extended periods will cause it to heat and get very hot

the waterpump will be pumping the water around fast at highway speeds about 2500-3000rpm and will pass through the radiator very quickly not taking off much heat and it will just build up and get hot

I'm sorry but that's not right either.

For any given cooling system, faster flow through the radiator means more cooling.

The problem with running no thermostat is that it will only make your car run cooler when it doesn't need to, ie when the thermostat would normally be closed and the cooling system isn't working hard. But the minute you get to a situation where it would have overheated with a working thermostat in place, it is just going to overheat again anyway.

If you have a working thermostat and your vehicle overheats, it is overheating even though the thermostat is fully open. So the same thing is going to happen with your gutted thermostat.

And meanwhile, you are running your engine outside the temperature range it was designed for. How much this matters depends on the engine,and running cool is not as bad as running too hot, but it's still not good for engine life or even fuel economy.

[offroader-rama]

even little old me no dat da water have to stay in ya wadiator wong enuff to cwool dwon or da wotor will won hot .
now thats plain stupid
hence why we have thermostats to slow the flow to allow the air to cool the water in the radaitor
vorno your not stupid are you you know what your on about

[bogged]

even little old me no dat da water have to stay in ya wadiator wong enuff to cwool dwon or da wotor will won hot

that makes as much sense at that thing in your avatar photo...

[offroader-rama]

THE THING
thats what i might call my fc thanks bogged but you dont like it why?? as a work truck / tow truck I think it rocks makes sence to me anyway!!
as for the quote, its a dig at a know it all, for calling me plain stupid and then saying something simply dumb

[chimpboy]

Well, I didn't actually call YOU stupid, I just said that running without a thermostat is stupid, which it is.

And from what you've written now, as far as I can understand it, which is not much, you don't actually understand how a thermostat works, so it's no wonder you don't understand why it's stupid not to use one.

The thermostat stays closed to restrict coolant flow so that your engine warms up faster. When the engine is at running temperature, it opens up as much as it needs to so that there is more coolant flow through the radiator, because more coolant flow through the radiator gives better cooling.

The radiator is constantly full of coolant. The idea that the coolant has to "stay in there long enough" to cool is just plain wrong. There is always coolant in there, it is just a question of which coolant. Ideally, it should be coolant that has just come out of the hot engine a nanosecond ago.

If it's flowing more slowly, cooling is less effective, not more effective. This is because of a simple and undisputed law of physics, which states that the rate of cooling of an object (in this case, the water is the "object") is proportional to the difference between the object's temperature and the ambient temperature. This means that the longer the coolant is in the radiator (ie, the slower the coolant flow), the less effectively it is cooled by the ambient air. It follows that the faster the coolant flows, the more effectively it is cooled.

I'm sorry if you can't follow this, but you really should believe me on it. The only people you ever hear of saying it's smart to run with no thermostat are backyarders who don't know much about cars. They are always the same people who have ongoing, endless problems with their vehicle but will do anything except actually fix the problem properly.

Now, the reason that running with no thermostat isn't going to help with overheating when you're doing higher revs and slower speeds off-road is that the thermostat's role is only to reduce the cooling action of the radiator when the engine is still cool. It does less and less as the engine gets hotter and it (the thermostat) opens more and more.

If your car was previously overheating, the thermostat was either stuck partially closed (in which case you just need a new thermostat), or it was fully open and your cooling system still wasn't up to the job. Running with no thermostat will just make the car take longer to warm up, probably keep it from getting to a proper running temperature most of the time, and then make no difference whatsoever when it matters most - when the cooling system hits the limit and your engine starts overheating.

But like I said above, the middle of the gauge seems like a reasonable place for the needle to sit, and the question is just whether it remains steady there once the motor's warmed up. It won't stay steady if you don't run a thermostat, because maintaining a stable temperature is exactly what the thermostat is for.

[rOd]

Ive got a headache.

I need to liedown.

[Zac Zec]

Patrol temp gauges are SHIT Get an aftermarket one to c what temp you are really running.

[shakes]

how many race cars dont run thermostats and they go through a hole lot more flogging than i give

But they do run TUNED restrictors where the thermostat was and water pumps sized to suit too hey.

Patrol temp gauges are SHIT Get an aftermarket one to c what temp you are really running.

we have the money shot

Simon

[Ezookiel]

...If it's flowing more slowly, cooling is less effective....

Are you sure that's what you meant to say?
Wouldn't this comment make him correct in removing a thermostat so that it flows quicker, if in fact slower is less effective?

[offroader-rama]

makes no sence to me either ezookiel
besides I never said it was ever over heating, and so far its temp has read the same with or with out the thermostat and with the new sender i was just wanting to double check, and as others have said its seems its right now and it was wrong before, as for not running a thermostat it is unwise if flow is wrong ie.to fast or to slow more of an issue in up and down climates and a real issue in injected cars as the computer reads the temp to alow for fuel, ie cold temp, computer adds more fuel like a choke, it thinks its like a cold start, bigger fuel bill.
but if the resticter keeps flow right then i cant see the problem but i will be putting one back in as i dont want to be seen as backyarder because thats wrong i work in my front yard

[Ezookiel]

I run with a thermostat in mine, despite all the issues, because the one time I did try without one it made no difference, and because the temperature then went berserkly up and down all over the place.
On long downhill sections it would drop all the way to cold, then on the next climb it would still get very hot. Those ups and downs worried me as metal doesn't like expanding and contracting lots and lots.

However sheer logic would imply that water staying in the radiator longer would indeed cool more, but at the same time the other water out in the engine would stay THERE longer as well, and therefore get much hotter. So it would appear to be little gain to hold the water in the radiator longer to cool it longer, as the water in the engine is only going to get much hotter and therefore take longer to cool it down when it has it's turn in the radiator.

One thing from my school science classes that I did remember was that the faster water flows the colder it is, as I remember thinking at the time that this made sense based on many bushwalks I'd done where crossing an almost stagnant creek was always MUCH warmer than crossing a fast flowing one. Wouldn't fast flowing water be cooler in a car cooling system also?

So basically this thread has left the whole thing more cloudy than before.

Oh, and today, despite not climbing any major hills, it was very pleasing to see my temp gauge go up to 45% and stop there only ever climbing the tiniest notch to 50% on one long shallow hill.

I'm sure the end of MY cooling issues is now just a few minor steps away.

[chimpboy]

...If it's flowing more slowly, cooling is less effective....

Are you sure that's what you meant to say?
Wouldn't this comment make him correct in removing a thermostat so that it flows quicker, if in fact slower is less effective?

Yes, it's what I meant to say.

No, it wouldn't make him correct in removing the thermostat, because the thermostat only reduces coolant flow through the radiator when the engine isn't warmed up yet. So sure, removing the thermostat will make the radiator cool the engine more, exactly when you want the engine to get warmer.

It also wouldn't make him correct when he says "we have thermostats to slow the flow to allow the air to cool the water in the radaitor", because that is exactly the opposite of what thermostats do. And it doesn't make him correct when he says, "da water have to stay in ya wadiator wong enuff to cwool dwon or da wotor will won hot", which I take to mean, "the coolant has to stay in the radiator long enough to cool down or the motor will run hot", because that is also the exact opposite of how a cooling system works.

There's nothing "cloudy" about it. It's not a matter of opinion; cooling systems are pretty simple. More flow, more cooling, less flow, less cooling. Simple!

So, I don't think I am being pedantic or a know-it-all, I am just trying to correct some incorrect information so the next person who comes along with a cooling system issue doesn't read this and get a totally wrong idea of what thermostats are for.

[offroader-rama]

this is all well and good in a patrol which has a huge radiator standed.
but your saying if you take out a thermostat (not that im suggesting it) in a say a barina, festiva or dawoo and then raced down the high way that it cant run hot because the water flow is sped up.
I'd say you were wrong, sorry, but they have a poor little radiator that needs the coolant to hang around in there a while to cool down so it can cool the motor down.
now we all now that heat rises and there for the hot coolant is pushed in the top of the radiator and buy the time it gets to the bottom its cooled down enough to get sucked by the water pump back into the engine were the heat transfer from the engine back into the coolant where its pushed back into the radiator over and over. Ok nothing new
but now if we picture the radiator has a line which it would have where the hot coolant meets the cooled coolant, maybe a 100mm wide or so but its there, now the faster that coolant where pushed / pulled by the water pump the lower down the radiator that line would be untill that line where the bottom tank and well then its history.

[jessie928]

ideally, what the patrol needs is to piss the origional water pump off altogether along with the thermoustat and run a adjustable speed, electronically controlled.

Jes

[chimpboy]

I'd say you were wrong, sorry, but they have a poor little radiator that needs the coolant to hang around in there a while to cool down so it can cool the motor down.

now we all now that heat rises and there for the hot coolant is pushed in the top of the radiator and buy the time it gets to the bottom its cooled down enough to get sucked by the water pump back into the engine were the heat transfer from the engine back into the coolant where its pushed back into the radiator over and over. Ok nothing new

Water flows through the whole radiator because of the pressure from the water pump, not because heat rises.

I don't know whether a barina would overheat with no thermostat, because I am not sure how they are put together. But it might, because in a lot of cars the thermostat works two ways; it doesn't just restrict flow through the radiator, it also diverts flow directly back to the pump (ie it doesn't just dead-end the coolant when the motor's cold, it allows it to "free-wheel" back to the pump without going into the radiator at all, just circulating in the engine). So with no thermostat at all, in some cars you might get a lot of coolant diverting straight to the pump without going through the radiator at all.

But if it did overheat in that case, it wouldn't be because there is more flow through the radiator, it would be because with no thermostat the flow to the radiator is reduced anyway.

Seriously. By your logic, as the coolant flow gets slower and slower, it cools the engine more and more. So in that universe, stopping the flow altogether should make the car super cool, which is obviously wrong.

Try and think of it this way. The engine makes heat at a certain rate. The radiator can dissipate heat at a certain rate. The thermostat is just like an automatic volume knob on the radiator controlling how much heat it can dissipate, designed to match the engine's heat-making rate.

You pull the knob off and the max volume is still the same; it just isn't being controlled properly any more.

but now if we picture the radiator has a line which it would have where the hot coolant meets the cooled coolant, maybe a 100mm wide or so but its there, now the faster that coolant where pushed / pulled by the water pump the lower down the radiator that line would be untill that line where the bottom tank and well then its history.

I think it's more of a continuum where it goes in hotter and comes out cooler, with the temperature reducing gradually as it flows through the radiator and no sharp line between hot and cold.

I'm sorry if I sound like a grumpy old man, but you know, radiators didn't fall from the sky leaving us with the hard job of working out exactly how they work. They were designed to work a certain way, so we KNOW how they work:

In automobiles with an internal combustion engine, a radiator is connected to channels running through the engine and cylinder head, through which is pumped a liquid. This liquid is typically a mixture of water with ethylene glycol (a.k.a. antifreeze).

The fluid moves in a closed system from the radiator to the engine, where it conducts heat away from the engine parts and carries the heat primarily to the radiator. The radiator is typically mounted behind the vehicle's grille, with outside air driven through the radiator by the vehicle's forward motion, often supplemented by a fan. The radiator transfers the heat from the fluid inside to the air, thereby cooling the engine. A system of valves and/or baffles is usually incorporated to simultaneously operate a small radiator inside the car; this small radiator is called the heater core and serves to warm the interior cabin. (Noting that heating the interior of the car also helps to cool the engine, this is the reason for the mechanic's instruction to turn on the heating system if the car is overheating.)

The engine temperature is controlled by the thermostat, a wax-pellet type temperature operated valve.

When the engine is cold, the thermostat is completely closed and allows heat to build up in the engine, by allowing water to circulate only through the engine (and the heater core). When the coolant reaches the thermostat's activation temperature, it begins to open, allowing water into the radiator. The thermostat will open as far as needed to maintain the design temperature, by metering the amount of water going to the radiator. How far the thermostat opens depends on many factors, such as engine power (=heat) produced, the air flow through the radiator, outside air temperature. The basic process is entirely mechanical, the only electrically controlled part is the electric cooling fan,unless on a older car that uses a clutch fan which is on when the engine is on.

Note that the size of the radiator is usually chosen such that it can keep the engine at the design temperature under the most extreme conditions a car is likely to encounter (such as climbing a mountain, while fully loaded, on a hot day)

The invention of the automobile water radiator is attributed to Karl Benz. Some engines have an additional oil cooler; a separate small radiator to cool the motor oil. Cars with an automatic transmission often have extra connections to the radiator, allowing the transmission fluid to transfer its heat to the coolant in the radiator.

Turbo charged or supercharged engines may have an intercooler, which is an air-to-air radiator.

http://en.wikipedia.org/wiki/Radiator

For more detail and cute animated diagrams: http://auto.howstuffworks.com/cooling-system.htm

[offroader-rama]

I never said that the water was push through buy heat rising I know its the water pump hence the name pump.

as for a diffenitif line in the radiator I said around a 100mm its a big line.

In the radiator the water comes in at a very hot temp goes out a lot cooler dont know what temps but you probably do and this happens in area of lets say a 400mm deep radiator, and its cooled buy the air rushing through, so at some point there will be a area/line accross the radiator where hot meets not so hot coolant, probably the area that gets the best air flow.
I agree that if its there too long the motor will suffer by not getting the cooler coolant it needs to keep cool but if its not there long enough how will it cool down.
Now lets talk horses for courses most cars that come out of afactory were designed by a roocket scientest who could get a job at nasa so the system works very well.
but lets say you were to put a 454 in a standed gq if used only on the road the standed radiator would probably do (I said probably) but if it was built up to do some comp work, it would cook real quick because the water would be push around to fast to be cooled even with a good set of thermo fans and no thermostat (which according to chimpboy would help because it would flow faster ??) so to solve the problem, you put a big arse radiator in, maybe a extra tank to hold more water in, same fans as before and use a thermostat to slow the cooler coolant from entering the engine, and as your truck gets hotter the thermostat will open allowing more coolant in, but the fact that its there slows the coolant down so it has cooler coolant to reteave from.
if it where to flow faster then only cold coolant would be entering the engine and we all know thats not good.

[rvh96]

a radiator is nothing more than a heat exchanger in this case liquid to air. the rate of heat transfer depends on how much air passes though the fins and how much water though the tubes. the more air the greater cooling no mater what,
but the faster the water flows doesnt always mean greater cooling ,sure more water is cooled in volume in a givin time but temps are higher than if the water speed is slowed down but less water is cooled in the same givin time. this is where a happy medium has to be achived so that the water is being cooled at the same rate as it is being heated by the engine the themostat controls this to a point but is mostly worked out by radiator size pump volume hose size etc. so changing the flow rate can cause problems either way

[chimpboy]

but the faster the water flows doesnt always mean greater cooling ,sure more water is cooled in volume in a givin time but temps are higher than if the water speed is slowed down but less water is cooled in the same givin time.

This is still incorrect. The air takes heat from the coolant 100% of the time the coolant is in the radiator. It takes more heat if the coolant is hotter, and less heat if the coolant is cooler, because the cooling rate is proportional to the difference between the air and coolant temperatures. The longer some coolant sits in the radiator, the cooler it gets. It follows that the difference between its temperature and the air's temperature is smaller, and it follows from this that the air then takes less heat from it per second.

Obviously, coolant is hottest when it has just come out of the engine. Therefore (for max cooling) you want as much of the coolant in the radiator as possible, at any given moment, to be coolant that has come from the engine as recently as possible. To achieve this, you want maximum coolant flow.

Anything less than maximum coolant flow = less than maximum cooling.

Coolant flow is limited by the thermostat to reduce cooling. The reason you want a "happy medium" instead of maximum flow is simply so that you don't overcool the engine.

Yes, if you have a giant engine with an inadequate radiator, then pulling the thermostat out completely may in theory help, because even a fully open thermostat presumably chokes flow a tiny little bit. But this is only the case if your radiator is not actually up to the task of cooling the engine properly, and again the solution is to fix your radiator, not to pull the thermostat. So for the millionth time, pulling out the thermostat can't magically fix a marginal cooling system.

This isn't some opinion I've cooked up after staring at my radiator for a while and deciding I'm a radiator expert, this is just some basic factual information about how a car's cooling system works and is designed to work. Sheesh, it's no wonder there are always people with persistent overheating problems if a tech forum like this can't get the basics of how it's meant to work right.

But anyway, I give up! I'm only trying to help people y'know.

[offroader-rama]

I got a wonderful Idea lets shake hands and agree that a thermostat is best left in a engine, not your hand and that it is there to provide a happy medium between cooling and over heating a engine.
yipee

[offroader-rama]

what does a thermostat do again
jokes jok please do not reply