Outer Limits 4x4 Board

chimpboy wrote:....cooling systems are pretty simple. More flow, more cooling, less flow, less cooling. Simple!...

Glad to hear it, cause that's what logic says should be the case, also means I can pretty much piss off those who tell me that going to a highflow pump instead of the standard Patrol pump, won't help my cooling. A high flow pump would mean a greater flow, and hence greater cooling, whereas I've had some try to tell me it would flow too fast and not have time to cool, which seems pretty ridiculous to me.

So, once the turbo and fuelling are done, if there's still a problem (and maybe even if there isn't as a Just-in-case) I might look into the highflow electric pumps advertised in some of the 4wd mags

Certainly can't hurt can it? (other than putting even more electric load on my alternator)

im sorry but the only way speeding up the flow of water will help cool the water in the motor is if you have a 100% efficient radiator which is near impossible , maybe if you place a radiator in that is twice the size as a standard one but even then the faster the flow of water the faster the flow of air required as the air can only absorb so much heat once the air reaches the water temp it aint gonna remove any more heat ,so if the water is flowing faster than the air can take out the heat your putting hot water back into your motor
the thermostat on my mav has a restrictor so if the water temp gets too hot and the thermostat opens right up it actually blocks (or reduces the flow ) the water flow allowing the water in the radiator to cool down enough to cool the motor
so unless you have a flow problem causing it to get hot increasing the water flow wont help

just my 2.5 cents

thank you

The cooling system is basically 2 heat exchangers.

1) Heat from engine is transfered to coolant through water jackets

2) Heat from coolant is transfered to air through rad.

Simply put, if you speed up the water pump you would have to either increase the rad size or pump a lot more air through the existing rad but you would prbably have to do both.

However this might not always work as water coming out of the rad may be nice and cool but restrictions in the water galleries within the block and head slow the water down too much and it still gets too hot within the engine. I think this is what happens with TB42's!!

Jimmy

TOUCH DOW

I forgot the N in DOWN try again
TOUCH DOWN

Hey guys,
New to this forum and this is probably not the best choice for my first post here, but chimpboy is correct in everything he has tried to explain to you. Most of you seem to be thinking of each component in the cooling system as an individual item not as part of a complete system. Yes, the longer the coolant stays in the radiator the cooler it will be when it goes back into the engine, but also the slower it will flow through the engine, so you will get an engine that is cool where the coolant comes in and a lot warmer just before the coolant leaves the motor. The bit about "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." is probably the most important, this is scientific fact, not some theory made up by chimpboy to make him look smart. Also the air flowing through the radiator will not just reach a certain temp then stop cooling, as there is a constant supply of 'new' cooling air flowing in. Having coolant flowing through faster will also result in a more evenly cooled motor. Sorry if this is a bit hard to follow, I'm not the best at trying to explain stuff, but I try anyway.
Most of what has been said is realy not that important to the average joe, just remember that not having a thermostat is bad, mainly because it will take a lot longer for the engine to warm up, and this is when your engine will wear the most. A bigger radiator will help cool in extreme conditions, as will a bigger water pump, BUT the bigger water pump will do bugger all if your radiator is struggling allready.

Thanks.
Dave.

"but chimpboy is correct in everything he has tried to explain to you"
We haven't argued his points just put a different angle on his views

"Yes, the longer the coolant stays in the radiator the cooler it will be when it goes back into the engine"
yes but the water on the other side of the system will stay in the engine longer and get even hotter!!!!or you can leave it in there the same amount of time and force more air through or use a bigger rad.

" is proportional to the difference between the object's temperature and the ambient temperature." is probably the most important, this is scientific fact, not some theory made up by chimpboy "
Where did anyone say that??????

" BUT the bigger water pump will do bugger all if your radiator is struggling allready."
This has already been said.

"but chimpboy is correct in everything he has tried to explain to you"
We haven't argued his points just put a different angle on his views

Some people have, and I think they are on the wrong track, just trying to help them.

"Yes, the longer the coolant stays in the radiator the cooler it will be when it goes back into the engine"
yes but the water on the other side of the system will stay in the engine longer and get even hotter!!!!or you can leave it in there the same amount of time and force more air through or use a bigger rad.

Thats what i said, or at least, what I was trying to say.

" is proportional to the difference between the object's temperature and the ambient temperature." is probably the most important, this is scientific fact, not some theory made up by chimpboy "
Where did anyone say that??????

Just getting back to the people, mainly person, that seems to want to argue everything put forward.

" BUT the bigger water pump will do bugger all if your radiator is struggling allready."
This has already been said.

My bad.

Dave.

So have we actually help this guy solve his overheating problems???

who's got a over heating problem
I started this forum by asking where other peoples temp gage sat , because after doing a head gasket,
NOT I SAID NOT NOT NOT from over heating but from some w ker setting up my gas wrong and leaning it out, so i replaced head gasket sender and put on a set of extracters for good messure and a full service, oil , leads , plug filters points , etc... when i had finished the gage read half before i started it read less than a quarter which it had done for three years and two thermostats so i wanted to see where other peoples temp gage stayed it seems i was been paraniod.
then this almigthty bitch fest broke out wwwhhhaaattttssss uuupppp
NOW I dont believe any body is calling chimp boy a lyer but most of us disagree with one little bit of trivial mater of which Ive come to agree to disagree.
that flow does not equal cool coolant I beleive if you put a bigger water pump,take out restrictions like thermstat ,redirect hoses what ever it takes to get more flow will not help with out a bigger radiator.
like ive said before in a standed car on a standed road with a standed driver you would be fine
but if you are reading this you probably dont like standed cars, roads and your not standed driver, so your out side the circle, heavy right foot, big trucks, with big wheels to turn, and big ruff hills to climb, so all those revs and free flowing coolant and lack of air to radiator MEANS LOTS OF HEAT, so with out a reserve of cooler coolant in a bigger radiator with thermos your fun is going to be short lived. I'm shore like me, when you where starting out you also found out the hard way.

HAVE A NICE DAY EVERBODY AND THANKS FOR YOUR IMPUT
P.S. I BROUGHT A NEW THERMOSTAT TODAY

" started this forum by asking where other peoples temp gage sat , because after doing a head gasket"

Shows how much attention i pay!!!!!



Hope it goes well with the new thermostat

cheers jimbo

its aford not a nissan wrote:the air can only absorb so much heat once the air reaches the water temp it aint gonna remove any more heat

This seems to be the point of confusion. If more of the coolant in the radiator has just come from the engine (which is the case with faster coolant flow, consider it in terms of the average time spent in the radiator by all of the coolant currently in there), then the difference between air temperature and coolant temperature is greater, and therefore the exact same amount of airflow can absorb more heat than it could with slower coolant flow. [Another way of looking at this is that really, you are trying to exchange hot metal for hot air as fast as possible, and therefore you want your medium of exchange to be moving as fast as possible.]

Of course more air flow would be nice and helpful too. In fact, the more air flow the better, exactly the same as with coolant flow. Why would there be some "happy medium" for coolant flow, and not a "happy medium" for air flow? Don't you want the air to "stay near the radiator long enough" to cool the water?

And as for you Jimmy... you've disappointed me, and that's all I've got to say!

Offroader-rama: I'm happy to agree not to spend the rest of my life arguing about this with you...

cheers chimpboy I'm posting a new question you might be interested in

the coolant is circulating the air is being replaced continually with fresh cool air so the faster it pass,s the better. the faster the coolant flows though the radiator the less time it is expossed to the passing air and it does not matter how you try to explain otherwise this is fact

"And as for you Jimmy... you've disappointed me, and that's all I've got to say"

HAHAAHHA Why????

Sometimes it is hard to get my point across!!!!

I ahve done quite a bit of heat exchanger work at uni and in my employment including some interesting pracs where u are able to plot flow v's temp and so on BUT sometimes in the real world things work a lot different and there is no quick/easy fix or explanation.

Tell me what i said wrong and i probably will change what i said because i may have not meant that!! I know my brain works on a similar frequancy to yours most of the time heheheeheh


Cheers

Jimmy

"the faster the coolant flows though the radiator the less time it is expossed to the passing air and it does not matter how you try to explain otherwise this is fact"


Your right but why slow down the water when u can increase the air flow???

Why not speed up the water flow and speed up rad fan and or increase rad surface area?


Anyway its late and i have to leave work!!!

"the faster the coolant flows though the radiator the less time it is expossed to the passing air and it does not matter how you try to explain otherwise this is fact"



NOT TRYING TO BE SMART GUYS,
WORST CASE SONAREO WHEN YOUR OFFROADING ITS FORTY DEGREES OUTSIDE IN THE SHADE AND YOUR BOGGED AND YOUR CAR DIDN'T COME OUT WITH THERMOS IF YOU PUSH IT, GET FRUSTRATED, SAY BAD WORDS, AND TRY YOUR HARDEST, YOUR NOT ONLY GOING TO COOK, BUT FRY THE BUGGER IT DOESN'T MATTER HOW FAST THE FLOW
"THIS IS REALITY"
ITS ALL ABOUT A HAPPY MEDIUM AS SAID
OR AS I PREFER OVER KILL PUT A BIGGER RADIATOR AND LET THE THERMOSTAT HOLD THE COOLANT BACK, AS A RESERVE OF COOLANT IF NEEDED OH AND BIG FANS.

I VE CREATED A MONSTER THATS ALSO A FACT

an easy way to see if your radiator and cooling system is up to the task is if you put a temp guage on AFTER the radiator to see if the water is in fact being cooled enough
1/ if this temp reading is quite cool and you are having heating problems then you may have a flow problem
2/ if this temp reading is high then the radiator may be blocked or the fan isnt working properly or (dare i say it) the water is flowing too fast an the cause could be either faulty thermostat or no thermostat

ive tried mine without a thermostat and on the hwy it actually ran hotter i put it back in without the little bleeder pin and it ran cooler but still had temp fluctuations then i put a screw in that hole so it was sealed with no flow at low water temp and now it sits steady at about 2mm under half it dont move at all

I brought a thermostat today(no thermostat at moment) putting in tomorrow because I drove down the high way and mine too came up to three quarter and that is with a v8 radiator, so flow did not equal coolness sorry to those that disagree, it was trialed and failed

Mine sits on 1/4 most days when the temp is dunder 25 degrees and just cruising around town. When i get on the hwy it goes to about or just under 1/2.
When the temp outside is above 30, cruising around the guage is just under half but when i sit on 100km/hr it goes above 1/2 but under 3/4 which i think is a little too high!!!!

A few weeks ago when i was searching around for a new head or my mates tb42 i spoke to some guys that reco heads and they said that ppl still come in with cracked heads even after they have had water pump mods and head mods that give more coolant to the back of the head!!!

What is the solution???

You should be able to tow a heavy trailer in hot weather with a/c on without having the motor overheat!

I rang Nissan to see if they could provide a cooler thermostat but they could only supply me with an 82 degree one. In the manual i ahve it says that there is a 76degree one, but that may only be available overseas

Jimmy

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

Correct!

Engines are built of different metals that expand at different rates when heated, we have 'clearance tolerances' when we assemble them for that reason. That is why it is important to get to operating temperature asap so the the clearances are at the optimum for minimum wear.
Most wear happens when the engine is 'warming' up.

There would have to be a cooling system specialist on here somewhere who could write a paragraph and STOP THE MADNESS

we are all specialest didn't you know as for the madness its becoming entertaining

Good point, I did chuckle out loud numerous times, until my missus told me to shut the >&%$ up.
She was wacthing desperate housewives

I dont think an "expert" is needed as every vehicle i different and no 1 person has the answers to everything

Anyway i did some basic tests last night driving home from work. It was around 31-32 degrees outside and driving anywhere at 80km/hr or below the temp was actually under 1/2. I crept up to 90km/hr in 4th and the gauge moved a little but then crept up to 100km/hr and it went just above half!!!!!!! I repeated this in 5th and it was the same.

This has nothing to do with my fan as there is enough air flow at this speed. I cant beleive the difference between 80km/hr and 100km/hr.

I'm still searching for that 76 degree thermostat!!!!! but in the mean time i will pull my rad out and give it a clean inside and out, flush my engine a few times and also drill a couple of small holes in the thermostat and see if that does anything.

dont tell chimpboy he he he our secret

(This has nothing to do with my fan as there is enough air flow at this speed. )
before i bought my car i took it for a test drive and around town it sat on 1/4 as soon as i got on the hwy the temp rose to just under the hot mark i pulled over and found that the fan wasnt engaged went back to car yard told him to put another fan in he winged and ummmed an arrred and finally he put another one in then the temp didnt go over half on the same stretch of hwy
this was in my case anyway and i didnt have spotties in front either on the other hand the radiator wasnt in the best shape either but it didnt leak and went well for another 6 months till i got a newie

oh and a couple of weeks after i got it i found the thermostat was stuck open which didnt help in warming up in the morning

You probably won't read this, as this is an old topic, but my job is to trouble-shoot helicopters and I spoke to sikorsky about its trans oil heat exchangers (fluid radiator). If you look at it as a linear scale if flow is too slow the heat source will overheat the fluid and the ratio at which it is replaced by cooled fluid won't be enough to control the overheating (thermal runaway). If you take the other extreme, if fluid is pushed through the radiator at very high speeds the radiator might as well be just another vessel for the fluid to flow through (ie: a hose) so dependent on the ratio of engine size and the amount of heat it produces, to the size of the heat exchanger, flow dose matter. This is determined at manufacturers specs. so mod'ing will require trial and error, either it needs a restricting body (thermostat) in the line to allow for adequate thermo-siphon (so you dont get the eng. recieving inadequatley cooled fluid from the rad. just pushed thru with pressure), or there are other reasons the system is over haeting. And yes obviously the thermostat on and andequate system will change the volume to allow for quicker warm up and better temp. holding. Could also be too much of a restriction, therfore needing a better rad. or other factor, which is why people pull them out in the first place. (I've done it on my lux with a holden v8, helps offroad, but gets hotter at 100km/h, and big hills. I need to look at all the issues myself too.) (ie. better rad. and then put the thermostat back in, it's only a temp fix, with highway downside sacrifices.)

Cheers hope this shines a new light on things.