Twin thermo's???

[gupatrol]

Have got 2 thermo's on my vk because of the gilmer drive.

Its running at around 200-240. It should be running cooler then that.

Any ideas??

[Tom_1569]

Thermos are alot different then the original fan. They only come on to cool the radiator, where as an engine fan is spinning all the time (unless its a clutch one) but they are alot better at removing the hot air from the entire engine bay, where as thermo's only seem to cool the radiator efficiently. The only plausable solution i can see is, make the fans come on earlier which is probly your case because its the water temperature thats to hot. Also you could hook them up to the brakes, so they come on automatically everytime your foot is on the brake.

[gupatrol]

Ay mate,

I run them from a switch on the shifter, turn them on as soon as I start up. Still runs hot.

[commsirac]

What size/brand electric fans, how big is the radiator? How many rows?

If you are running a modified engine on the original sized radiator, electric fans will struggle.
From what you say the motor runs hot all the time, even when you are cruising, so even the best electric fans you can get aren't going to be your answer, if you need them at cruise, its going to get very pear shaped at idle.

More radiator might be needed, however, going to a four or five row radiator can be counter productive unless you are using an engine fan, solution thin core high performance aluminium radiator.

Are you sure there are no other problems in your cooling system?

[gupatrol]

AY champ,

Thanks a heap for your input.

No other problems from what I can see, have flushed the radiator, have the thermo's running all the time. It is a original radiator from what I can see, with a mild modded engine.

What other problems could there be mate?? And how would I check them??

Thanks a heap for your help.

[feistl]

Have you checked the thermostat. When they fail they can get stuck closed/half closed which will cause problems.

What mix of coolant are you running?

Again, a bigger/high performance radiator will help.

[Tom_1569]

Commsirac and feistl have very good advice, except i doubt it is the thermostate, if the thermostate didnt open the car would boil to the point it will sieze.
Unless its an extremly worked 202, their has to be something wrong in the cooling system though. Id be having the radiator flushed, pressure tested and refilled with coolant/water. Also get the motor flushed, it could have a blocked water jacket.
The only other things i can think of is to put the original pulleys and fan back on and see if that makes a difference. OR a possibility is the gilmer drive water pump pulley is infact a different size and not flowing enough water or even to much therefor not giving it enough time in the radiator to cool the water.

[commsirac]

The only other things i can think of is to put the original pulleys and fan back on and see if that makes a difference. OR a possibility is the gilmer drive water pump pulley is infact a different size and not flowing enough water .

Yes, thats a good point about the glimer drive pulleys, i was assuming that was driving a supercharger or something? and the motor was very modded, what is the glimer drive doing?

or even to much therefor not giving it enough time in the radiator to cool the water.

Tom, unfortunately, that's just an old mechanic's tale that probably is being passed onto new mechanics, LOL. The faster the water circulates, the better it is for heat exchange, the gains get correspondingly smaller as the coolant speed increases, so increasing coolant speeds beyond accepted values wont achieve significant further improvement
. What perpetuated the myth perhaps, is the association between increasing the speed of the water pump and overheating problems that sometimes resulted. Basically the wrong conclusion being drawn, the motors sometimes overheated as the water pump would cause cavitation of the coolant at higher speeds, effectively reducing circulation through the radiator.

[Tom_1569]

.....Tom, unfortunately, that's just an old mechanics tale. The faster the water circulates, the better it is for heat exchange.
What perpetuated the myth perhaps, is the association between increasing the speed of the water pump and overheating problems that sometimes resulted. Basically the wrong conclusion being drawn, the motors sometimes overheated as the water pump would cause cavitation of the coolant at higher speeds, effectively reducing circulation through the radiator.

I've always wondered if theirs any truth to that, but everyone seems to swear by it so i've just adopted the theory to. It kind of works the way they explain it. But your does make more sense, i think ill sit on the fence until i can study it more, caus right now both work in theory haha.

[gupatrol]

Ay fellers, thanks a heap for the advice.

Gilmer drive is doing **** all, was on there when I bought it. Engine is a 308, worked a little. Have flushed the coolant twice, flushed the block also.

Hmm, which way should the thermo's be turning?? That could be it?? Suck air through the radiator or push it from the engine bay??

Coolant is straight coolant from supercheap.

Once again, thanks a heap.

[commsirac]

Fans, have create an airflow that moves the air from the outside of the radiator towards the engine....otherwise they work against the air flow when you are driving and could indeed cause overheating on the move, wouldnt make too much difference at idle. That being said, you need to see if it is the fans that are your problem.

The vehicle should be able to travel at 50km/h+ in any ambient temp without the electric fans. If it cant, there is simply not enough natural(ram) air flow to keep things cool, and/or the rad isnt big enough/good enough. So do test if the vehicle can go 50km/h without overheating with the fans off first.

Just a basic test you can do for system circulation: compare the temp of the top radiator hose with the bottom one....just putting your hand on them. If they feel very similar in temp and the motor is running hot, chances are you circulation is okay, if you can feel a difference, coolant flow through rad is too slow....could be thermostat, blockage, water pump.

[gupatrol]

Ay bud,

I can tell ya right now that she wont go 50km without fans. Did about 10k the other day and she was at about 220 when I got home. That was with the fans on.

Will do that test shortly.

Thanks bud

[commsirac]

Ay bud,

I can tell ya right now that she wont go 50km without fans. Did about 10k the other day and she was at about 220 when I got home.

......., 50km/h+, I was referring to travelling at a speed of 50km per hour or more..

[gupatrol]

Oh sorry mate. Will give it a test when i can.

Thanks bud

[commsirac]

I've always wondered if theirs any truth to that, but everyone seems to swear by it so i've just adopted the theory to. It kind of works the way they explain it. But your does make more sense, i think ill sit on the fence until i can study it more, caus right now both work in theory haha.

Tom, good to see you at least have an open mind on the matter.

Slowing the water flow down reduces the heat transfer, thats what the thermostat does, opening the thermostat....increasing the flow, increases heat transfer

Yes, I realise the advice is possibly 100/1 in the myth/fact ratio, thats only because thats possibly population ratio of "myth believers/(people who have at least done thermodynamics 101" is about the same.

Here's a link you can start your research with; 14 Rules for Improving Engine Cooling System Capability in High-Performance Automobiles

[tanka5.7]

you can run a clutch fan with gilmers

[vk383]

easy way to tell if the fans are sucking air in is to hold a piece of paper in front of the grille,if the fans suck it to the grille and hold it there they are sucking air properly,if it falls straight to the ground they are prob spinning the wrong way.I have au thermos and a desert cooler 4 row radiator with my 500 horse 383 and the temp gets up to about 195 f cruising at about 110 kmh,Through town temp drops to 180 f