thermostat, thermo fans and switch questions

[Shakotan_Aaron]

i have a few questions here after searching.


1. what temp is the normal toyota 2jzgte thermostat? 82deg rings a bell? or was it 76...

2. the temp rating of a thermostat, is that when it is at the fully open position? i.e. it begins to open before it reaches that temp? or is this when it beings to open? if so what sort of temp is it fully open at?

3. after reading thermo switch discussion i have come to the conclusion that it makes sense for the switch to be in the bottom as i have always been paranoid about the situation of the fan switching on and staying on cooling the hot incoming coolant and the thermostat not opening causing no water circulation!

so question No.3 will a sensor in the lower hose be fine? or would i be better off getting a bung welded into the thermostat housing?

4. Tridon thermo switches are they really very accurate and reliable?

5. what temp for on/off switch? remember its going in the lower rad hose not top.

im thinking 90deg on 85deg off? or 92deg on 87deg off?


6. is the normally closed type relay worth the extra work with relays? seems a descent bit more complex for my brain


7. been looking at falcon thermo fans, either AU or EL look to be the go, AU looks to be about 10cm thick, are EL any thinner? i have a issue with space otherwise i would be running a stock viscus fan. Also is there a model to avoid, remember reading something about EF(?) having one fan 12v and the other 6v? sounds odd to me.


if someone wishes to help with a reply probably easier to put the number then reply.

thanks

[wilbo666]

1) 82°C pretty sure.

2) My understanding is that the rated temperature is when the thermostat starts to open, but you could test this to confirm
TSRM for MA70, but similar / applies. http://www.cygnusx1.net/Media/Supra/.../CO/CO_008.gif

3) Lower hose is fine, I think you'll find that the there is mention of using a speco brand temp holder to achieve this in that thread? (or perhaps it is another thread)...

4) Short answer - yes they are accurate and reliable

5) Either of those should work, Pretty sure mine is 90-85.

6) Depends if you want the system to be 'fail safe', that is the wire to the coolant sensor breaks or becomes disconnected the fans come on. If you want fail safe then you usually need to setup as normally closed.

Cheers
Wilbo

[river]

Hi,

In the thermostat thread I think Toy77 was going to put a temp sensor in the bottom hose, in addition to the standard temp sensor on the top. Any update on this, as it would be interesting to see the temp differences between the in going and out going water.

seeyuzz
river

[Shakotan_Aaron]

thanks for the reply, if its only just opening at 82deg then switch off at 85 maybe too cold, 87 would be more appropriate it seems. the fact that the water transfers the heat that far (from engine, threw radiator and hoses) before it can cycle is also kinda surprising. the more im thinking about the cooling system the more it raises more questions.

the normally closed type seems like a good idea for the whole fail safe thing but a tad more tricky to set-up. the thermo fan i had on my corolla was just wired directly into a switch using power from the stereo, not even any relay id just switch it on when i felt like it. however this next car doesn't have a motor that i can pick up for $50>free so i want to do everything properly and safely to ensure reliability and longevity.

i seem to remember watching a old topgear vid where the JUN r33 had 3 water temp gauges!

[river]

Hi,

In regards to thermo open/fully open.. the thermostat on a 2T/2TG engine opens between 80.5 and 83.5 deg and is fully open at 95 deg.

Not sure if later engine models have this (approx) 15 deg range between starting to open and being fully opened.

seeyuzz
river

[Shakotan_Aaron]

perhaps the on/off switch needs to be even higher or the fans and thermostat will fight each other for control of cooling.

Thanks for the tip for the adaptor, your correct they do list them.

http://www.speco.com.au/gauges_ad.html


any idea about question number 7?

[Chello]

I know not really what your after, I have a ef ford radiator setup in my Hilux with the fans set to always on with a manual override switch in the cabin. The switch is hooked to a red light which activates so I remember they are switched off. The reason I did it this was is because if I do river crossings, not what you intend to do, I can turn them off so the water doesn't smash the blades. The EF/AU fans are really effective and not all that loud, once you have the motor going you can't hear them, well that's me anyways

[LeeRoy]

2. It starts to open there. Obviously it will open faster the higher above this temp the engine gets, or the longer it stays at the opening temp.

3. It's silly to base cooling of the engine on the effectiveness of the radiator. If the water coming out of the engine is really hot then it's a safe bet that the 'cooler' water being fed into it is not cool enough, so the fans need to turn on.

5. Go the top hose - see my point above.

6. Yes - provides a good safety margin for the switch failing.

7. Spal make a super thin thermofan - maybe worth looking into. I will warn that they're not cheap though.

[Silly Rabbit]

Spal fans FTW...but yeah as Leeroy said not the cheapest.....have been told by more than one source that they are a lot better than the "other brand". Currently putting one in my car and it shifts a massive amount of air for its size.

[Shakotan_Aaron]

2. It starts to open there. Obviously it will open faster the higher above this temp the engine gets, or the longer it stays at the opening temp.

3. It's silly to base cooling of the engine on the effectiveness of the radiator. If the water coming out of the engine is really hot then it's a safe bet that the 'cooler' water being fed into it is not cool enough, so the fans need to turn on.

5. Go the top hose - see my point above.

6. Yes - provides a good safety margin for the switch failing.

7. Spal make a super thin thermofan - maybe worth looking into. I will warn that they're not cheap though.

after reading the thermo switch discussion ive come to a conclusion that the lower hose is the way to go.

ive made a 2jz/7mge hybrid viscus fan so ill give that a go. yeah spal do look good, cant trust some claims! some $30 ebay fans claiming to pull 2650CFM, if it did half that id be impressed.

Spal fans FTW...but yeah as Leeroy said not the cheapest.....have been told by more than one source that they are a lot better than the "other brand". Currently putting one in my car and it shifts a massive amount of air for its size.

pretty sure that i could fit a 14" and 12" on my core. we are going into winter so ill see how it goes for now, if these any doughs ill change before next summer, if the car is going before next summer.


thanks for the replys.

[CELICASUPRA7M]

So the water coming into the motor through the bottom hose is at 90deg, how hot will the water coming out of the top hose be ? IT will be freaking hot indeed.

[river]

Hi,

Wouldn't you have a much lower temp switch from the bottom hose? So, for example, you'd switch on the fans at (say) 65 deg (temp of the bottom hose) instead of (say) 90 deg from the top hose?

seeyuzz
river

[Bananaman]

I know not really what your after, I have a ef ford radiator setup in my Hilux with the fans set to always on with a manual override switch in the cabin. The switch is hooked to a red light which activates so I remember they are switched off. The reason I did it this was is because if I do river crossings, not what you intend to do, I can turn them off so the water doesn't smash the blades. The EF/AU fans are really effective and not all that loud, once you have the motor going you can't hear them, well that's me anyways

Haha i have to disagree on the noise... I have EF fans as well, and if both are on they're pretty audible.. if you are moving then no, but idling, the noise of the fans when they kick is as loud as teh car itself pretty much.. on a 1J with 3" exhaust. Mine were wired permanently on when i got the car, switched it to be 92 on 87 off, best thing i've done. In my car they don't need to be on most of the time (they generally kick in when i stop) - figure less load on the alternator most of the time is a good thing.

And to answer some of the OP's other questions, if it is in your MX83 with standard radiator, when i looked into it i thought the AU fans were too big?

And re using normally closed switch, i did it this way, bit of stuffing around but i think worth it - if the switch mucks up i know i can just unplug it to force fans on

[wilbo666]

Hi,

Wouldn't you have a much lower temp switch from the bottom hose? So, for example, you'd switch on the fans at (say) 65 deg (temp of the bottom hose) instead of (say) 90 deg from the top hose?

seeyuzz
river

Might be worth noting that xJZ have the thermostat after the bottom hose on the engine. Not the conventional thermostat -> top hose arrangement.



Cheers
Wilbo

[Shakotan_Aaron]

So the water coming into the motor through the bottom hose is at 90deg, how hot will the water coming out of the top hose be ? IT will be freaking hot indeed.

if you havent already, have a read threw the thermo switch thread which discusses placement. good food for thought in there. how i understand it, the radiator only needs fans when its not cooling enough, if the water temp is entering at 100 and exiting at say 82 then its doing a fantastic job. if its exiting at 90 degrees then it needs help from the fans.

if its switched from the top say the switch is tripped and water is coming out of the engine at 100 fans on, its exiting at say 77, the thermostat is 82 degrees, the thermostat is simply going to adjust the flow and close meaning the water going threw the engine is reduced and the water exiting the motor at the top will be even hotter as it has spent longer inside the engine. without the fans on, water maybe exiting at 85 keeping the thermostat open and the water flowing well threw the engine.

by rights thermo fans should normally only operate at low speed or when stationary as the natural airflow threw the radiator should be sufficient, if its not then the radiator is either crapped out or not efficient enough for the application from my opinion. im always open to new ideas but this is how i understand it.

also i dont really know how efficient radiators are so example temps are simply used as an example.

Hi,

Wouldn't you have a much lower temp switch from the bottom hose? So, for example, you'd switch on the fans at (say) 65 deg (temp of the bottom hose) instead of (say) 90 deg from the top hose?

seeyuzz
river

if its swithced on at 65 degrees at the bottom then once the engine gets upto temp then the fans will run constantly and thermostat will close again.

Haha i have to disagree on the noise... I have EF fans as well, and if both are on they're pretty audible.. if you are moving then no, but idling, the noise of the fans when they kick is as loud as teh car itself pretty much.. on a 1J with 3" exhaust. Mine were wired permanently on when i got the car, switched it to be 92 on 87 off, best thing i've done. In my car they don't need to be on most of the time (they generally kick in when i stop) - figure less load on the alternator most of the time is a good thing.

And to answer some of the OP's other questions, if it is in your MX83 with standard radiator, when i looked into it i thought the AU fans were too big?

And re using normally closed switch, i did it this way, bit of stuffing around but i think worth it - if the switch mucks up i know i can just unplug it to force fans on

im using a new china/ebay alloy radiator for mx83, i tried a jza80 radiator (figured it was rated for the motor) but it was too tall.