gq overheating problem>td42 turbo?? anyone fixed it yet?

[purplebus]

will change on weekend....
thanx shoul i try it without one>???

mine was worse without one but a friend fixed his by removing his.?
dont forget to put a small hole in the outer rim to let air through/ help flow.

[coxy321]

will change on weekend....
thanx shoul i try it without one>???

Definately not! Just try a new one first and report back. Go easy on the thermostat housing bolts (they're fragile) and have some quality gasket compound handy too.

[love ke70]

i know theyre meant to auto bleed themselves on the GQ, but it makes me wonder if its not bled properly, causing the overheat, im assuming your running a new rad cap with the new rad? what pressure?

[sidewayz]

mine is 95 gq td42 with gu turbo running 12/13psi

was starting to get a bit warm with the standard rad. original 2 core plastic tank shitter, full of mud and bent fins.

have just fitted a adrad 3 core copper tank item today. was 470 inc gts. will let u know how it goes...

[Clanky]

Just saw this while at work (Outers is blocked) . Might be relevant to some peoples heat problems

http://www.exploroz.com/Forum/Topic/751 ... x%3fpn%3d2

[coxy321]

Just saw this while at work (Outers is blocked) . Might be relevant to some peoples heat problems

http://www.exploroz.com/Forum/Topic/751 ... x%3fpn%3d2

Good find!

[twodiffs]

Have many people actually driven an N/A td42? The low point where the max torque comes in is neither here nor there on this engine unless in low range towing tree trunks.....possibly, power higher up in the rev range is what makes the engine, don't miss out on it based on an assumption only, 3600 will do no harm ever and probably be kinder than lugging along spinning slow when there is no need.

The engine comes alive at about 3000 give or take a little and then thunders toward 3800-4K. How can that be given it's torque spec??

Disclaimer by thunders above i do mean the most impressive part of the engines power band is right here in 3rd gear, and by impressive I mean a td42 type level of impressive:)

I do mate (until I get the turbo fitted). I regularly tow a tandem trailer filled with premix or building materials or a transport trailer with a 2tonne digger. We've got some mean hills that the td42 won't pull these trailers on in 3rd cog. I find the best and easiest on the donk is in 2nd gear and hold it between 1800-2200rpm. It'll pull like a freight train all day in that range and won't overheat.
I usually try and keep it in 3rd for as long as possible before changing down, when the revs drop under 1600rpm and black smoke is pouring out then I change to 2nd. No black stuff and the engine is not over revving.

[Troll00]

Ok, yeterday was a hot hot day, driving home from work with air con on at first... warmed up to half, turned air off, was sitting in traffic M5.. warmed up just over half, got the shit took next exit.. put foot down, got to just under Hot, pulled up while my mate grabed a sixPac of Jimmis... crept up a little more.... could here a slight bubbling sound... drove of got back onto menagle road , cruiseing bout 80-100ks started to drop. got home and it was just over half.....!! so i think my factory gauge is ok. but why why why does she get warm.......!!!!

Have you checked to see if the head is cracked best way to do this is to take the radiator cap off and then get it to operating temp if you are gettting bubbles in the water it's a bad sign if you do, or get a compression test to see

[ANDREWGQ 351]

on the pirate4x4.com home page they have a tech article describing all the cooling miths like thermostats, water amd air flows. makes a lot of sence and is opposite to what most so called experts say.

[fnqcairns]

on the pirate4x4.com home page they have a tech article describing all the cooling miths like thermostats, water amd air flows. makes a lot of sence and is opposite to what most so called experts say.

let me guess, fast water flow because of a missing thermostat harms cooling?? Always been a minor frustration whenever someone says that...goes against all the laws of physics...shoot we wouldn't even have TV or computers and still live under a bark roof if this held true in any way what's so ever.

[coxy321]

on the pirate4x4.com home page they have a tech article describing all the cooling miths like thermostats, water amd air flows. makes a lot of sence and is opposite to what most so called experts say.

let me guess, fast water flow because of a missing thermostat harms cooling?? Always been a minor frustration whenever someone says that...goes against all the laws of physics...shoot we wouldn't even have TV or computers and still live under a bark roof if this held true in any way what's so ever.

If you're implying that running no thermostat has no effect on an engine's operation - then i would have to say you are wrong. Not having the restriction/regulation (thermostat) usually makes the car run too cool, which is not a good thing.

[ANDREWGQ 351]

The thermostat is to regulate the temp as you say, but even when it is fully open it reduces the flow, this is a bad thing. Removing it helps a system which is struggeling in other areas, but cold days are a problem

[fnqcairns]

on the pirate4x4.com home page they have a tech article describing all the cooling miths like thermostats, water amd air flows. makes a lot of sence and is opposite to what most so called experts say.

let me guess, fast water flow because of a missing thermostat harms cooling?? Always been a minor frustration whenever someone says that...goes against all the laws of physics...shoot we wouldn't even have TV or computers and still live under a bark roof if this held true in any way what's so ever.

If you're implying that running no thermostat has no effect on an engine's operation - then i would have to say you are wrong. Not having the restriction/regulation (thermostat) usually makes the car run too cool, which is not a good thing.

Only implying the physics, I keep reading where people use the idea that the water can travel too fast (in engine terms and because of the lack of a thermostat only and often related directly at TD4.2 engines) past a surface to absorb or give to a surface's heat somehow, the thermal conductivity of water doesn't work this way.

As long as a surface is contacted by water with all other perimeters remaining the same it doest care what speed the water is doing past it as it gives up it's heat.

In a close system the total effective heat budget stays the same irrespective of water speed alone and actually if water speed induces some turbulence instead of a more lamina flow then this can in effect aid absorption or dissipation.

[coxy321]

on the pirate4x4.com home page they have a tech article describing all the cooling miths like thermostats, water amd air flows. makes a lot of sence and is opposite to what most so called experts say.

let me guess, fast water flow because of a missing thermostat harms cooling?? Always been a minor frustration whenever someone says that...goes against all the laws of physics...shoot we wouldn't even have TV or computers and still live under a bark roof if this held true in any way what's so ever.

If you're implying that running no thermostat has no effect on an engine's operation - then i would have to say you are wrong. Not having the restriction/regulation (thermostat) usually makes the car run too cool, which is not a good thing.

Only implying the physics, I keep reading where people use the idea that the water can travel too fast (in engine terms and because of the lack of a thermostat only and often related directly at TD4.2 engines) past a surface to absorb or give to a surface's heat somehow, the thermal conductivity of water doesn't work this way.

As long as a surface is contacted by water with all other perimeters remaining the same it doest care what speed the water is doing past it as it gives up it's heat.

In a close system the total effective heat budget stays the same irrespective of water speed alone and actually if water speed induces some turbulence instead of a more lamina flow then this can in effect aid absorption or dissipation.

I'm not talking about the water moving too fast to absorb the heat from the water jacket surface (never even thought of it that way to be honest), but rather the flow of coolant cycling too fast and removing too much heat via its normal process.

I'm reffering more to flow regulation rather than speed too, just to clarify.

[its aford not a nissan]

hmmm time to stir the pot i think

for starters yo cant control how fast the water flows through the block except with rpm , it is constantly flowing ( some early model motors may be different ) and recirculating , speed of the water wont effect the waters ability to absorb heat in this part of the motor as the thermostat will keep the water there till it opens and lets cooled water in from the radiator
the speed of the water travelling through the radiator however does have an effect on how much heat it can take out of the water , the radiator can only take out / transfer so much heat with X amount of air flow , if the water travells to fast the radiator will be over run with hot water exceeding the amount of heat the air can take out then passing that hot water ( or not sufficiently cooled water ) back into the motor , problem is that the motor has all this heat it wants to get rid of but the water going into it is already hot or not cool enough to maintain the heat in the motor , so the thermostat opens a bit more speeding the water flow through the radiator even more , this is when you have lost control of your water temp

heres my example
my mav ( td42t ) was getting hot going up big hills , it was reaching up to the hot mark , i replaced the thermostat but it made no difference at all , so i replaced the fan hub and it did make a little difference but when it came to this hill it still ran too hot , so i got the radiator cored out but that made no difference , i was getting pretty frustrated by now , so i drilled a couple of holes in the thermostat but all that did was make it run too cool around town and still got too hot going up big hills and now my fan was constantly roaring , pretty much everything i did didnt help or made things worse and my temp guage was going all over the place. so i figured instead of trying to make it run cooler i would try and make it run hotter and see if i could get the temp more stable , i got my first thermostat which had no holes in it , pulled the little pin out which pushes the thermostat open and ground a couple of mm off it so it would open later ( about 90 deg ) the temp guage now sat just under 1/2 on the guage instead of a few mm above cold , first thing i noticed that it got up to running temp faster , i also noticed the motor was quieter , the fan hardly ever engaged , i could feel more power ( probly because the clutch fan wasnt engaged all the time ) and the temp guage never moved , till i got to this problem hill where it always got hot , to my surprise the temp guage only rose to just above 1/2 no matter how bad i laboured it or reved it out

so all i did was to increase the radiators efficiency by increasing the temperature difference between coolant temp and ambient air temp and slowing down the waterflow through the radiator by increasing its operating temp ( probly goes in hand with making the radiator more efficient at removeing heat)

it worked so well i ditched the clutch fan and i am running au falcon thermos, although with the thermos it does get a little hotter towing the camper trailer up big hills with the a/c on but still nowhere near as hot as it used to

[Clanky]

By all means, remove the thermostat like they do in race car engines.
However race car engine builders do other things as well like fitting water restrictors to reduce water flow and changing diameter of the water pump pulleys.

If an engine cooling system has been designed around what the engine is designed to do, then it should work effectively.
If it needs to be modified, then you need to consider the flow on effect of the mods.

P.S "itafordnotanissan", you should look at where the temp gauge sender is located on the TD42. Mine is in the return hose from the rad. If yours is the same then I am guessing that the thermostat mods you did are keeping the heat in the block and therefore the sender is not seeing the true engine temp - just what water temp is coming back from the rad. As the thermostat is a bypass system, your engine might be overheating and you not knowing about it. Would be worth checking, and if its all OK this could be an interesting mod and easy to do!

[its aford not a nissan]

the temp sender is in its factory position and it pretty much reads the temp of the coolant that comes out of the head , the hole you see under the thermostat goes strait back to the water pump and the coolant gets sucked down through this hole and back through the block and up to the head , im also useing a very small overflow bottle due to space constraints and it doesnt use any coolant so i am assumeing it doesnt boil the coolant anywhere in the block ( what i consider overheating )

[Clanky]

SOunds interesting. The theory goes against what one would think to be correct, however your 'real world' testing seems to be on the money.

[thehanko]

SOunds interesting. The theory goes against what one would think to be correct, however your 'real world' testing seems to be on the money.

makes sense to me, though i can see sense in thinking otherwise.

Heat converters work most efficiently when the difference in heat is greater.

i.e slower moving water which is a bit hotter by the time it leaves the block, will lose more energy in the radiator due to the great difference in ambient / water temp. so it would then re enter the block comparatively cooler (greater change in temp).

However could this also cause problems if the water entering the block and exiting the block are too different? or is the difference so small its irrelevant?

[its aford not a nissan]

dont forget that the water pump is constantly recirculating the water in the block , any water from the radiator is mixed with the water in the block that is already hot , so unless the thermostat is wide open ( which would mean you have lost control of the cooling system ) the amont of water going into the block should only be enough to maintain the opening temp of the thermostat , the cooler this water the less water it needs to maintain temps